Filter ? need some help

[Joejoe80]

I read your comment as "if you're using plants to outperform algae growth, you have a problem in your pond". IF plants are working, there's no problem. My pond, without plants, would not function as planned and I'd no doubt have lots of algae. That's because it's designed to use plants as part of the ecosystem. IF you have a planted pond that's still filled with algae, THEN you have another problem - too many fish, too much food, too much decaying organic material, etc.

Again it’s the bacteria in those plants that’s processing and creating the nitrogen cycle without the bacteria there is no nitrogen cycle.
Those plants are exporting nutrients absolutely. But it’s the bacteria that’s creating the nitrogen cycle.
It is your biological filtration that is keeping your pond in check. Your plants are only helping.

if what you say is true .If you absolutely have to have plants in a water system. It don’t matter what type of system. If it is a pond fish tank anything your fish would not be able to exist in a fish tank or pond without plants then.
This is 100%. False

Again it’s the bacteria that is in your pond your water your plants your rocks and whatever else that you have in that pond your liner believe it or not.
it’s all these thinks is where bacteria grows.
it is the bacteria. the biological filtration that is keeping your pond healthy not your plants.
Your plants are only helping
Bacteria is and always will be the first and only thing you need to create a nitrogen cycle bacteria processes everything all of it. Plants will only export nutrients they will not process and create the nitrogen cycle.

also notice when breeding fish actual breeders don’t have plants in their systems they have bare tanks with basic filtration and lots of Aeration

I have thorough knowledge of filtration.
All my knowledge of water and filtration comes from keeping full reef tanks.
I’ve been keeping both freshwater and saltwater tanks for over 30 years

fresh water whether it be tropical, cold water, indoor aquarium ,indoor pond or outdoor pond is nothing compared to what you need to know when it comes to water and filtration In keeping a reef tank.
This is a fact.

There is nothing in my 30 years of keeping fish and helping people with their systems that I have not seen or corrected. I I don’t mean over the Internet I mean physically in person.

your pond works.
I guarantee it’s not overstocked or overfed that’s the reason why your pond works With just plants.

I have so much knowledge about filtration and water and I want to help people so much because there is such a huge amount of misinformation about filtration out there it’s ridiculous and this is why people have such problems with their systems.

your system absolutely 100% works.
you absolutely can have a pond with only plants I am not arguing that at all. you do not need to have mechanical filtration I am not arguing that at all.

but your system is not working because of the way you’re thinking it’s working.

it’s not your plants it’s the way you’re keeping your system.
Your not overfeeding.
it’s how many fish you have in your system. It’s not over stocked. And I can say these things without knowing because if it was you’d have all kinds of allergy problems.

what kind of maintenance are you doing do you constantly have to remove leaves and debris do you have to do water changes?
this is where mechanical filtration and plants start to help.

The reason why I say system is because water and filtration the nitrogen process the process of keeping your water clean and healthy is all the same no matter what type of system it is freshwater saltwater pond lake ocean.


i’m not trying to come off as a jerk you can’t type emotion or feelings so please don’t take any of this the wrong way.!!!!!!!!!


I’ve been through it all I have too many friends with tanks and what not that are filled with algae and look like crap. That can’t figure out what’s going on with their system.
That’s spend hundreds and hundreds and thousands of dollars on protein skimmers and algae scrubbers and UV filters. Then when you ask them well are you doing water changes. Are you keeping up with your carbonate hardness your DKH levels calcium amino acids.(that’s more salt water)
Then they tell you well know maybe I do a water change once a month.

I have taken over maintenance of peoples systems and have had friends say to me what do you do that I don’t.

I don’t over feed

I don’t overstock.

I Research the animal I’m purchasing the requirements how big they get.

I do the physical maintenance the cleaning of the filters the water changes on a consistent basis.
I’ve kept full-blown reef tanks without dosing anything nothing calcium amino acids nothing just by doing water changes once a week. with the right type of Salt. While friends of mine have all this fancy equipment. pumps in high Tech feeding systems. and I have to come over every week and start cleaning and maintaining their systems and showing them how to do it.

I’ve got too Rich friends specifically. That constantly do this to me.

And I’ll be honest I get jealous!!!!
I wish I could have all those fancy hi tech gadgets and pumps and lighting systems

I got one friend that spent 3 grand on the lighting system for 20 gallon tank. Mind you I’m using PC and getting 3 times the growth
Luckily they haven’t moved into ponds yet.!!!!!

 

[Jhn]

@Joejoe80

Think we are debating in circles and I am being unclear about bacteria And the nitrogen cycle. if there is an ammonia source in the pond it will start the nitrogen cycle, whether there are plants or not, never meant to imply that plants would replace bacteria in the nitrogen cycle. Plants will lessen the severity of it as it starts though, as they do use ammonia as well as nitrates to grow. Bacteria population is the back bone of the biofilter of any water feature with life in it. I agree with everything you are saying about bacteria and it’s necessity. If you leave goldfish or koi in a pond unchecked you will eventually run into problems no matter what type of filter system you use ie natural or man made filters.

Where we disagree is using plants to combat nuisance alga, you see it as a flaw in the system. When it is just another means of nutrient export or banking whichever you want to call it. No one on here believes you must have plants in your pond in order for it to be successful. Have kept ponds with no plants and just a filter. No filter system is a fool proof maintenance free substitute for good husbandry practices and common sense. Me I prefer to pull plants as the need to be weeded back around the pond, as opposed to cleaning filters

 

[Joejoe80]

@Joejoe80

Think we are debating in circles and I am being unclear about bacteria And the nitrogen cycle. if there is an ammonia source in the pond it will start the nitrogen cycle, whether there are plants or not, never meant to imply that plants would replace bacteria in the nitrogen cycle. Plants will lessen the severity of it as it starts though, as they do use ammonia as well as nitrates to grow. Bacteria population is the back bone of the biofilter of any water feature with life in it. I agree with everything you are saying about bacteria and it’s necessity. If you leave goldfish or koi in a pond unchecked you will eventually run into problems no matter what type of filter system you use ie natural or man made filters.

Where we disagree is using plants to combat nuisance alga, you see it as a flaw in the system. When it is just another means of nutrient export or banking whichever you want to call it. No one on here believes you must have plants in your pond in order for it to be successful. Have kept ponds with no plants and just a filter. No filter system is a fool proof maintenance free substitute for good husbandry practices and common sense. Me I prefer to pull plants as the need to be weeded back around the pond, as opposed to cleaning filters

there is no disagreeing with anything you just said I completely agree.

maybe It was I’m not clear. I don’t see plants as a flaw. they are beautiful.

I think that most people with these problems. Don’t understand what is actually going on. And what the root cause of there problem is.

And adding more plants is not really a fix neither is more mechanical filters. It will help.
But you will either need to keep adding more. Or your going to have to start doing water changes.
the system is going to crash. Unless you fix the cause.

Weather it is less waist, less organic material, not over feeding. Not over stocking. Thinning out the fish population.or Smaller fish. Would solve most of these issues.

Without having to keep adding more and more plants filters and what ever new high tech qizmo is out there.

but like I said who wants to constantly do water changes on a couple thousand gallon pond.

All I’m getting at is instead of adding or throwing more money into filters and what not.
Take a look at the most obvious.
Like I got an 800 gallon pond with five 15 inch koi in it. And the guestion is. The pond is full of algae. Or my fish are dying.

Tell us about your pond. I got a skimmer a pump. Turning my pond over 3 times an hour and lots of aeration and lot of plants
Well that’s your problem right there. It’s not the plants or filters. Is the size of the fish

Or I have 1000 gallon pond, but I only got five fish in it. that are small. but what I’m not telling is. I’m throwing handfuls of food in it every day.
The question is I have a algae problem my fish are sick.
well that’s your problem right there.

 

[Jhn]

there is no disagreeing with anything you just said I completely agree.

maybe It was I’m not clear. I don’t see plants as a flaw. they are beautiful.

I think that most people with these problems. Don’t understand what is actually going on. And what the root cause of there problem is.

And adding more plants is not really a fix neither is more mechanical filters. It will help.
But you will either need to keep adding more. Or your going to have to start doing water changes.
the system is going to crash.

less waist, less organic material, not over feeding. Not over stocking. Would solve most of these issues.

Without having to keep adding more and more plants filters and what ever new high tech qizmo is out there.

but like I said who wants to constantly do water changes on a couple thousand gallon pond.

Got ya kind of had a feeling we weren’t being clear. What I am thinking sometimes doesn’t come across in the written word when I go back and read my previous posts.

Haha definitely not into water changes on my pond, only time I do them is when I am topping off and forget an leave hose running

 

[Joejoe80]

Got ya kind of had a feeling we weren’t being clear. What I am thinking sometimes doesn’t come across in the written word when I go back and read my previous posts.

Haha definitely not into water changes on my pond, only time I do them is when I am topping off and forget an leave hose running

you should not have to ever do a water change in a pond plain and simple. with the right amount of plants the right amount of mechanical filtration established biological filtration.
Without overfeeding over populating and over sizing. the fish in the pond you should not ever have to do a water change in a pond.
At least in my opinion I don’t see any reason for it. In fishtanks and aquariums only reason why you need to do water changes is because they’re always overstocked and always overfed there’s just not enough water to dilute all that stuff and you cannot put enough plants to remove all that stuff.

In a pond though that’s a few hundred gallons or several thousand gallons as long as you have a decent amount of plants in there you don’t overfeed and it’s not overstocked or oversized fish you shouldn’t have to do a water change ever.

For instance in my pond it’s about 1200 gallons I got 13 small goldfish in there. If they breed next year I will be adding some sort of turtle or something to feed on them therefore hopefully keeping the population in control. Some will make it some won’t. this is a balanced ecosystem.
I already know judging from how big and fast mine have grown. I’m already over stocked. I know comets can grow to 4 inches. Allowing those fish to just breed and grow and breed and grow . is not a balanced ecosystem and no matter how many plants or filtration you throw in it you will eventually run into problems.

not to mention goldfish and koi are very dirty messy fish as far as creating waist

I get that we love our fish, but sometimes it’s better to get rid of them. Meaning find a more suitable situation and start new. Rather than let them grow so big or get so overpopulated that you can’t keep your water healthy.

if you have a pond that has been running for years with no problem. then all of a sudden you start having all kinds of problems like algae. I can guarantee most likely it’s because of either overpopulation oversized fish or overfeeding.
The reason why the pond runs so good for so many years is because this stuff takes a long time to build up. But once it does Bam everything crashes immediately. Then your left scratch your head as to why it happened. I’ve seen this happen to many times.

Fish start out small you get five of them say in a 600 gallon pond. I’m just throwing out numbers. Everything is good that’s ok.
next thing you know in 3 or 4 years or whatever. They are three times the size of what they where that’s not OK. Now there huge compared to what they were. making all kinds of waist. Now your feeding more because they are much bigger.
So you may not be over feeding your fish. But your over stocked over sized. And now over feeding the pond. Meaning with a increase of organic, inorganic material, and fish waist.

You have set yourself up for disaster from the start.

This is why researching is so important before you buy any animal

 

[Jhn]

you should not have to ever do a water change in a pond plain and simple. with the right amount of plants the right amount of mechanical filtration established biological filtration.
Without overfeeding over populating and over sizing. the fish in the pond you should not ever have to do a water change in a pond.
At least in my opinion I don’t see any reason for it. In fishtanks and aquariums only reason why you need to do water changes is because they’re always overstocked and always overfed there’s just not enough water to dilute all that stuff and you cannot put enough plants to remove all that stuff.

In a pond though that’s a few hundred gallons or several thousand gallons as long as you have a decent amount of plants in there you don’t overfeed and it’s not overstocked or oversized fish you shouldn’t have to do a water change ever.

For instance in my pond it’s about 1200 gallons I got 13 small goldfish in there. If they breed next year I will be adding some sort of turtle or something to feed on them therefore hopefully keeping the population in control. Some will make it some won’t. this is a balanced ecosystem.
I already know judging from how big and fast mine have grown. I’m already over stocked. I know comets can grow to 4 inches. Allowing those fish to just breed and grow and breed and grow . is not a balanced ecosystem and no matter how many plants or filtration you throw in it you will eventually run into problems.

not to mention goldfish and koi are very dirty messy fish as far as creating waist

I get that we love our fish, but sometimes it’s better to get rid of them. Meaning find a more suitable situation and start new. Rather than let them grow so big or get so overpopulated that you can’t keep your water healthy.

if you have a pond that has been running for years with no problem. then all of a sudden you start having all kinds of problems like algae. I can guarantee most likely it’s because of either overpopulation oversized fish or overfeeding.
The reason why the pond runs so good for so many years is because this stuff takes a long time to build up. But once it does Bam everything crashes immediately. Then your left scratch your head as to why it happened. I’ve seen this happen to many times.

Fish start out small you get five of them say in a 600 gallon pond. I’m just throwing out numbers. Everything is good that’s ok.
next thing you know in 3 or 4 years or whatever. They are three times the size of what they where that’s not OK. Now there huge compared to what they were. making all kinds of waist. Now your feeding more because they are much bigger.
So you may not be over feeding your fish. But your over stocked over sized. And now over feeding the pond. Meaning with a increase of organic, inorganic material, and fish waist.

You have set yourself up for disaster from the start.

This is why researching is so important before you buy any animal

I completely agree, have never intentionally done a water change on my ponds, as for the reasons you stated it is unnecessary And can even be counterproductive. My current pond is around 10,000 gallons, but is loaded with fish (koi, orfes, goldfish, catfish), all breed like crazy except for single catfish. Largest fish are a koi that is 20”-22” and the 20” catfish.

I will probably have to start giving fish away soon because I put A wide weave net high above my pond to keep hawks/birds of prey from snagging my terrapins, except now the heron can’t come by to thin my fish herd. Although, he usually starts with my favorite fish, so not to down on it.

I need to get my terrapins back in the pond this spring to start thinning the little ones out, although they can be pretty lazy on catching fish. Hopefully, the large catfish will be up to it’s job and suck some little guys down.

Yeah unfortunately most That come on here are because they have issues with their pond and is due to not doing their homework on how to properly care long term for the fish they buy, and how to proper setup their water features. That is fairly typical of most online forums though be it pond or reef forums.

 

[Sailfish]

Here’s another thing I just was thinking that I should’ve thought before. Even if plants to feed off ammonia and nitrates. They don’t break down the actual physical waste And detritus.
only the bacteria does that?

op stated they had a build up of detritus.
If there was sufficient bacteria per bio load detritus should not be much of a problem.??

Some build up you can’t help. Which is why we do some type of cleaning.

So I would say a lack of mechanical filtration. Such as a surface skimmer. allowing things to settle to the bottom and build up could be a problem among other things.
So they placed a submerged sponge filter/pump. In the pond. All that did was pull in all the gunk it could, and then get clogged.
Which would be common for that style filter pump.
This is why skimmers have some sort of collection net or spot for the bigger debris to be collected, as to not clog your spong, floss, or whatever else you have as filters inside the skimmer.
I do know with sponge filters. if they become clogged up the beneficial bacteria Can die off. And become anaerobic? Or is it aerobic? I forget . Which then will start to produce nitrates.
This happens in canister filters a lot if not cleaned out properly. Cleaned rinsed not scrubbed.

i’m not saying this was the whole problem but I guarantee it did not help

There is almost no detritus in the pond. Because of the extreme hot dry conditions this summer, the trees are going dormant and dropping leaves. I am scooping them out every day to prevent them adding nutrient. This and scrubbing out the algae has also removed all detritus. The filter sponge gets full of stuff though and is where the bacteria is supposed to live. It came already charges with bacteria

 

[Sailfish]

you should not have to ever do a water change in a pond plain and simple. with the right amount of plants the right amount of mechanical filtration established biological filtration.
Without overfeeding over populating and over sizing. the fish in the pond you should not ever have to do a water change in a pond.
At least in my opinion I don’t see any reason for it. In fishtanks and aquariums only reason why you need to do water changes is because they’re always overstocked and always overfed there’s just not enough water to dilute all that stuff and you cannot put enough plants to remove all that stuff.

In a pond though that’s a few hundred gallons or several thousand gallons as long as you have a decent amount of plants in there you don’t overfeed and it’s not overstocked or oversized fish you shouldn’t have to do a water change ever.

For instance in my pond it’s about 1200 gallons I got 13 small goldfish in there. If they breed next year I will be adding some sort of turtle or something to feed on them therefore hopefully keeping the population in control. Some will make it some won’t. this is a balanced ecosystem.
I already know judging from how big and fast mine have grown. I’m already over stocked. I know comets can grow to 4 inches. Allowing those fish to just breed and grow and breed and grow . is not a balanced ecosystem and no matter how many plants or filtration you throw in it you will eventually run into problems.

not to mention goldfish and koi are very dirty messy fish as far as creating waist

I get that we love our fish, but sometimes it’s better to get rid of them. Meaning find a more suitable situation and start new. Rather than let them grow so big or get so overpopulated that you can’t keep your water healthy.

if you have a pond that has been running for years with no problem. then all of a sudden you start having all kinds of problems like algae. I can guarantee most likely it’s because of either overpopulation oversized fish or overfeeding.
The reason why the pond runs so good for so many years is because this stuff takes a long time to build up. But once it does Bam everything crashes immediately. Then your left scratch your head as to why it happened. I’ve seen this happen to many times.

Fish start out small you get five of them say in a 600 gallon pond. I’m just throwing out numbers. Everything is good that’s ok.
next thing you know in 3 or 4 years or whatever. They are three times the size of what they where that’s not OK. Now there huge compared to what they were. making all kinds of waist. Now your feeding more because they are much bigger.
So you may not be over feeding your fish. But your over stocked over sized. And now over feeding the pond. Meaning with a increase of organic, inorganic material, and fish waist.

You have set yourself up for disaster from the start.

This is why researching is so important before you buy any animal

I cannot dechlorinate the town water. They changed to a resistant chemical so this is not usable for fish ponds, not even after ageing. Water restrictions do not allowed us to use town water to top up ponds, pools, bird baths or wash anything except ourselves and cloths (heavy fines ensue). Treated water goes back into the river which is a real environmental concern withe the chlorine change......

I have 3 Koi about 15 cm - 6" We generally don't feed them much unless we want to see them or they are looking a bit thin such as in early spring. They survive on insect fall and this keeps the growth to what the pond naturally supports. As it rained the other day, I now have 700 l of rain water. The 600 l pond capacity I gave you is an estimate and I need some for future filter cleaning too, so I am a bit reluctant to do a full water change just yet. In any case, I want the rain water to settle out some, before I use it as its full of dust because absolutely everything is coated in it. Looking at the pond today, the heavy colour seems to have settling out a few inches. If that continues to settle to a reasonable level, I may siphon out the lower layer.

 

[Joejoe80]

I wasn’t insinuating this was your situation. I was setting examples.
Man you have a mess on your hands.

it seems as if you know exactly what’s wrong with your pond, and you know exactly what needs to be done.
There seems to be many things happening out of your control

 

[poconojoe]

I read your comment as "if you're using plants to outperform algae growth, you have a problem in your pond". IF plants are working, there's no problem. My pond, without plants, would not function as planned and I'd no doubt have lots of algae. That's because it's designed to use plants as part of the ecosystem. IF you have a planted pond that's still filled with algae, THEN you have another problem - too many fish, too much food, too much decaying organic material, etc.

Listen to Lisa.
Plants are an important part of your pond's ecosystem.
Maybe I missed it, but what kind of fish do you have? How many are there and how big are they?

You need to get at the root or cause of your problem, not trying to "fix" the results of some sort of imbalance.

Something is out of balance. You probably have too many fish, feed them too much food or maybe there's a lot of sun exposure.

A lot of people on this forum don't use a commercial type filter. They use a bog filter that relies on plants that remove the excess nutrients. This starves the algae of nutrients. So the results are clear water. No UV lights, no filter pads to rinse.

To me, all the arguments going on in this post are just making it all too complicated than it has to be.

The way I look at it is simple...the fish poop which creates excess nutrients. The plants suck up a lot of those nutrients. Your beneficial bacteria in whatever filtration you have also feeds on it. Then you need aeration or at the very least some form of disturbance like a waterfall or fountain. It's all about keeping a balance and having enough oxygen.

 

[Sailfish]

I wasn’t insinuating this was your situation. I was setting examples.
Man you have a mess on your hands.

it seems as if you know exactly what’s wrong with your pond, and you know exactly what needs to be done.
There seems to be many things happening out of your control

Fair enough, Yes, I'm am very restricted in available resources and what I am allowed to do at the moment. The reason I joined this thread was to see if anyone knew enough to help me with testing the UV lamp, because it's a type I am not familiar with. I understand Flourescent UV and reactive coating filament bulb types. However, I had not come across the clear glass filament bulbs used in the pump. Testing resistance seemed to indicate open circuit failure even though it is new and looks intact. Early on, I could not detect UV using fluorescent material. Yes. I do know this UV is dangerous and I shielded myself from that. However, at the time I had not realised the holder has a safety cutout switch and so asked for help. Discovering the switch and taking the bulb out, I can measure high voltage, high frequency AC at the holder. So, now it makes a bit more sense in terms of power, voltage, currant and resistance
The new bulb shows some discoloration, indicating it is reacting to a currant, I have still not been able to confirm UV is emitted. It is hard to tell though, given the need for UV shielding. I'll try to test this again in dark conditions.

Ken.

 

[Sailfish]

Listen to Lisa.
Plants are an important part of your pond's ecosystem.
Maybe I missed it, but what kind of fish do you have? How many are there and how big are they?

You need to get at the root or cause of your problem, not trying to "fix" the results of some sort of imbalance.

Something is out of balance. You probably have too many fish, feed them too much food or maybe there's a lot of sun exposure.

A lot of people on this forum don't use a commercial type filter. They use a bog filter that relies on plants that remove the excess nutrients. This starves the algae of nutrients. So the results are clear water. No UV lights, no filter pads to rinse.

To me, all the arguments going on in this post are just making it all too complicated than it has to be.

The way I look at it is simple...the fish poop which creates excess nutrients. The plants suck up a lot of those nutrients. Your beneficial bacteria in whatever filtration you have also feeds on it. Then you need aeration or at the very least some form of disturbance like a waterfall or fountain. It's all about keeping a balance and having enough oxygen.

Yes, I know about pond plants, relied on them for decades but they are not available ATM.
3 Koi 15 cm - 6"
I do not believe that a small closed urban pond is sustainable without intervention. What I mean by "closed" is that nutrient goes in but not out. In a small urban pond debris, insects etc fall in and die, get eaten or break down releasing nutrients into the water. Water plants take up the nutrient, grow and parts of them fall into the water, break down etc. The point is that the biomas increases but no nutrient leaves the pond, it just converts into biomass which also incorporates carbon and other elements from the air. If the system is good, the amount of nutrient available in the water is very small because it's quickly taken up by plants and incorporated into their biomass. While there is a lot of recycling going on, biomass just keeps increasing and eventually the pond becomes a solid mass of roots. At some point a person has to intervene by culling out some of the biomass, effectively removing excess bio-nutrient-mass from the system. That activity may be pruning, removing roots, cleaning filters, whatever... It's not indefinitely sustainable without intervention. With a large rural pond, there may be flow through, flood events, animals taking fish etc combining to remove biomass. That does not happen with a small urban pond which left to itself would eventually become a bog. It can be many years between interventions though.

 

[Lisak1]

@Sailfish I may have missed it, but how long have you had these fish in this pond? If they are indeed koi (that term sometimes gets used incorrectly) your pond (at less than 200 gallons) is too small for koi. Maybe it's as simple as your fish have outgrown your ponds ability to deal with the waste. Hence an increase in nutrients and an excess of algae. Just a thought...

And you are correct that an eco pond requires "outside intervention" if you consider maintaining your pond plants as intervention. I guess I just consider that "gardening"! You mentioned having had lilies in the pond - have you (or do you) have any other plants growing in the pond?

 

[Lisak1]

And I do apologize - I realize this thread has wandered far off course from your original question. I know nothing about UV or electricity so I cannot comment on that.

I will say this. - I have never been a fan of UV filtration on a pond for two reasons: 1. killing algae in the water means you have water full of dead algae which is only going to lead to more algae and 2. what else does the UV kill that may be beneficial to your pond? But that's just my opinion. Lots of people use them and find them helpful.

 

[Sailfish]

@Sailfish I may have missed it, but how long have you had these fish in this pond? If they are indeed koi (that term sometimes gets used incorrectly) your pond (at less than 200 gallons) is too small for koi. Maybe it's as simple as your fish have outgrown your ponds ability to deal with the waste. Hence an increase in nutrients and an excess of algae. Just a thought...

And you are correct that an eco pond requires "outside intervention" if you consider maintaining your pond plants as intervention. I guess I just consider that "gardening"! You mentioned having had lilies in the pond - have you (or do you) have any other plants growing in the pond?

I guess the Koi have been in that pond 20 years or so. There is as far as I know, no reason Koi can't live in a pond this size unless you feed them. Like many fish, their size is limited by the food supply. Small pond = restricted food = small fish. I think a total of 18" of fish seems to be within limits. I'm pretty sure the cause is lack of established water plants. We only have one surviving plant, at type of upright lily and that isn't enough and doesn't supply shade. After a major clean, algae bloom is pretty normal until plant growth catches up, usually a month or so). Unfortunately this time, the water lilly died. We couldn't get plants and bought the pump last year and that was keeping it in check. This year though, has been horrendous with heat, drought effects and restriction and lack of quality rain water to top up. I had no option but to top up with the rain tank dregs which was not good water. Either that or netting out the leaves (stiring the detritus) or perhaps the bulb blowing caused a change from stringy to single cell algae bloom which the filter couldn't remove well. I have noticed that the filter does remove some of the material that could pass through and is taking longer to block. Perhaps that means I'm winning slowly.

I tested the bulb again, in a dark room and yes, it is causing florescence but a lot of visible light as well. Fluorescence doesn't seen all that strong though. Somehow I expected more efficiency and stronger UV. Yes, asking electrical questions was a desperate long shot.