Cloudy water and algae with UV lamp

[andreasy]

Hello everyone,

I really need some expert opinions here because I'm really in chaos.

First of all, here are the specs of my pond:

Capacity: 1000L
Koi: 3 large 2 babies 6 alpino frogs
Plants: 2 lillis + 2 which I don't know the English name
Filter: Laguna 5000 + 11w UV lamp (built-in)
+ waterfall.
Location: Cyprus (very hot sun ~40c)

Here is the story:

After 3 years of operation, the bottom of the pond was very dirty and at the time I didn't have a vaccum cleaner (now I bought one) so I decided to flush the water out, clean it and add new water. Very bad idea. It was too hot and the pond too dirty so it took me the whole day and 3 of the 6 large kois died (and they were pregnant also). The other 3 hardly survived but they are ok now. Anyway, I added new water and some of the old water for the bacteria and added the following additives into the water:

- sera crystal
- Sera algen stop
- Sera Bio humin
- Pond refresh microorganisms

I have been using the above frequently.

The problem is that despite the fact that I have a UV lamp which is brand new (I replaced it when I cleared the pond) and I use algae control additioves, there is too much algae in the pond and the water is cloudy. At midday there is new algae floating on the surface and in the evening it settles to the bottom. You cannot see the fish though because the water is green.

Yoday I opened the lamp chanber and I was amazed to see that the glass tube became matte (like white limescale) but that was only around the area where the lamp is visible. For example, around the 2 white/plastic edjes of the uv lamp the glass was clear. This means that for some reason, the uv lamp burns something around the tube when it's on. I have opened the lamp many times and even after 1 year this never happened before and I am sure that this is the reason of the algae problem.

I cleaned it with vinegar and the limescale went away.

I believe that Sera Bio humin could have caused the problem because it adds brown colour uv blocking agents to the water in order to make it UV resistant and maybe that could have interfered with the lamp.

Also, in the past my water was clear but at that time I didn't have the waterfall and the water was passing from another custom filter with active carbon, fibres, and others.

The most important thing for now is if anyone could explain to me what has caused the limescale on that area of the tube and then some advice of what I should do or how I should use the additioves in order to get rid of the algae.

Apreciate any help.

 

[Waterbug]

I've seen the limescale once on a UV. I'm not sure why this happens but I do know it happens very fast, like in a few days, and renders the UV ineffective. You have to keep checking and cleaning it. You're the first I've read who also had the same problem in the past 10 years. It could be a more common problem and people just don't notice.

My guess is the material is probably aragonite rather than calcite and is due to the higher temp of the water right against the glass. Here is a video that talks about it and there's good info in the comments section.

Could also be from a magnetic field, but the scale forms only on the glass over the element and trails off at the edges. So I assume it's the heat.

You've added a bunch of stuff to the water so it's impossible to tell what is causing what. I don't know why you're adding so much stuff, but that's a good way to kill fish and get unclear water. For example the Sera bio humin is suppose to make the water cloudy. It's also suppose to block UV rays...the same rays the UV filter is producing to kill algae...do you see a problem there? I read this often of people dumping everything they can get their hands on into the pond without really understanding what the stuff is beyond seeing the word "clear" some place on the label. The writing on the label is just there to get people to buy, they don't actually do what they imply. And if you read closely you will see they say things like "reduces" and "helps" but most don't say "100% guarantee clear water". Those who do offer a guarantee know most people will never return the product. Smart marketing.

My suggestion is to remove all the water, replace the water and only use the UV filter, making sure it's clean. That's a very large UV for that small a pond so it would kill all algae in under an hour depending on pump which you didn't mention. Once dead the algae would remain green until it decomposed. So with new water you should never have any green. If you see any green tint to the water you'd know your UV wasn't working and would need to be cleaned or whatever other problem fixed.

BTW, I'm amazed you were able to keep 6 large Koi alive in such a small pond. Impressive or very lucky. Or is 1,000 L a typo?

 

[andreasy]

Thanks for such detailed explanation :razz: . I'll have to do some study from the info you sent me but I want to avoid emptying the pond again since I almost killed all my fish last time. I just hope that all those additives will gradually fade away.

I know that in 1000L I should have max. 4 koi but they were quite healthy and happy at that time.

 

[Waterbug]

Many people would say the max number of Koi for 1,000 L would be zero. However with proper filtering, water testing it can be pulled off. Or luck.

 

[CometKeith]

Hi andreasy. Welcome to gpf and good luck with your pond. If you had less fish then there would be less waste and it would be much easier to maintain your pond. The waste is being converted to nitrate which is feeding your algae. That is why people recommend not to exceed certain bio-loads. Someone who is fairly experienced can have more fish because they know what to look for and how to solve problems that may arise. For your size pond maybe 3 or 4 medium size fish is about the maximum. My pond is more than twice the size of yours and I wouldn't venture to have Koi because they get too large. Most people recommend to have at least 1000 gallons for a single koi or in your case would be almost 4000 L.

 

[andreasy]

So I finally flushed 80% of the pond and added clean water. I couldn't accept seeing my pond with such a dirty water. I checked the quartz and it was clean after the last time (no limescale) so I don't understand why it couldn't clean the water. Maybe it was so dirty that the filter couldn't absorb all that sludge.

Now, another thought that I'm making for the limescale is that I used to switch the pump and the filter (uv) off at night with a timer. The fact that the water was standing still at the quartz during the night could cause the limescale. Anyway, I removed the timer and I will wait for a few weeks. I will also not add any additives except from the bacteria and water conditioner and see if that helps. At the end I may discover that my pond will need more frequent cleaning.

Here's a video of my clean water the next day of cleaning:

 

[Waterbug]

so I don't understand why it couldn't clean the water.

I added new water and some of the old water for the bacteria and added the following additives into the water:
- Sera Bio humin

Sera Bio humin blocks UV so the UV wouldn't work very well, or at all.

Now, another thought that I'm making for the limescale is that I used to switch the pump and the filter (uv) off at night with a timer.

Turning off a UV = green water. Must run 24/7. The scale forms only when the UV is on, it isn't a settling thing.

 

[andreasy]

Thanks again.

Can you please explain the following to me:

As youc an see in the video, my water was crystal clear right after I flashed and refilled. Now, I don't switch off the pump or filters so they work 24/7, even at night. I also checked the quartz sleeve and it was clear. However, at midday when the sun is most hot, I notice on the surface of the water green forming algae floating. Not that much as before but I can see it. In fact I can notice how it slowly forms until it becomes green mater.

Does this mean that my UV lamp is not working or is it still logical?

Sorry for insisting but I am trying to decide if my lamp works or not and to see if I should replace it with an external one as I was told that internal lamps tend to be inefficient.

 

[Waterbug]

If the green is forming on the surface like a slime that's a different species of algae. Not very common. Normally a skimmer handles that type of algae. Without a skimmer, or a skimmer that doesn't send water to the UV, this type of algae won't be effected by the UV as it just floats on the surface.

If the green is suspended in the water that is a species of algae killed by a UV.

I don't know the flow rate you're pushing through the UV. If water is pushed through too fast the algae isn't exposed to enough UV. When I install a UV I add a ball valve before the UV so flow can be turned down.

An 11 watt UV should be able to handle a pond 5 times larger than yours. So you have the power. If water turns green there is some problem with the flow rate or the filter.

I like external self contained UV filters. Combo units just make it harder to figure out what's wrong. For example if filter media clogs in a pressurized filter the flow to the UV can be effected and you wouldn't know. Just makes life more complicated imo. However, submerged and external are the same efficiency. There is no difference. The bulb doesn't know whether it's submerged or not. Where did you hear external are more efficient?

 

[CometKeith]

andreasy, The algae problem is being caused by your large bio-load=large amount of fish waste, and hot sun which helps algae grow. it will be very difficult to control the algae until you address the bio-load problem. Your fish are really pretty, but way too much for this size pond. All the chemicals and filters can not solve the problem until you address this issue. If you think about fish in the wild you would never see such a high concentration of fish in a natural body of water.

 

[andreasy]

Thank you guys. From my questions you can understand that I am inexperienced. Indeed I did this in my free time without any expertise or knowledge just by studying a few documents on the Internet. Anyway, your help was very valuable. I think that the first step I should take is to find someweher to sell 2 of my large Koi and leave only 1 large and the 2 babies.

 

[Waterbug]

Sun, heat, nutrients do cause algae to reproduce. Like any plant, given good conditions it grows. Move most plants indoors, or reduce nutrients or warmth, it won't do as well. Slowly over time it might even die.

So if you wanted water to be less green, like from a forest green to just a yellow green then limiting sun, heat and nutrients is an excellent method. It is virtually impossible to limit any one of these in a water garden to the level needed to kill all algae.

Clear water is a completely separate issue. Given our example plant...happy, growing well...apply a flame thrower. Pretty sure you're going to have a dead plant pretty fast. Apply the flame thrower once a day...pretty sure you're not going to see any sprouts from the roots even though they may be trying.

A UV works exactly like a flame thrower. When flow through the UV is right a UV can act as sterilizer meaning 99.9% of all life (algae, bacteria, virus, etc) going into the UV comes out dead. When flow is a bit more less life is killed and it's called a clarifier, but still enough algae is killed to keep it from reproducing enough to have green water.

When sized correctly for a pond, good water movement, a properly installed UV will kill almost every living suspended life form in the water. Given sun 24 hours a day, perfect warmth, perfect nutrients, perfect pH, perfect everything, suspended algae cannot reproduce fast enough to ever be visible. It's a flame thrower.