UV Sterilization for Dummies

[joesandy1822]

Ok, I give. I am sick of green water. If any of you remember me from a couple years ago, I wanted to go the "all natural" way. Ya, it clears up eventually. Last year, once the algae bloom started in early spring, it took until the end of August to clear up! That means I couldn't see the fish all summer due to pea soup. It sucked. I didn't succumb to any nasty chemicals, but I did try a gallon of stinky, expensive bacteria in a bottle to no avail (Microbe-Lift PL). Our pond is 3,000 gallons, bare liner, in full sun. We have probably 30 goldfish/shubunkins, although they do reproduce so I do not know how many babies. There are lots of frogs. Ducks do visit regularly, and I like them. Sorry. Even if I tried, they would come back. I have 7 water lilies, lots of plants around the perimeter in the rocks, usually have some water hyacinths and hornwort or anacharis. Once the lilies are mature, the surface of the pond is about 70% covered. We do not overfeed the fish. Actually we only feed them about once a week. There are probably some remnants of leaves in the bottom, but I can't see to get it all out. I've been here many times, and there is a long thread on here started by me about algal blooms: https://www.gardenpondforum.com/threads/algal-blooms.12270/ Here is my pond thread: https://www.gardenpondforum.com/threads/pool-to-pond-2013.12652/ if anybody wants to see.

I wasn't on here much last year due to, well, life in general being HARD. But here I am again begging more info from you experts. We LOVE, LOVE, LOVE our pond and all the critters it brings. We get so much joy from it. But it would sure be nice to see clear water and see the fish. I am so afraid of killing the good bacteria with the UV. I do have a lot of reading and learning to do. But I think we are at the point where we want to give it a go. My husband is afraid of the plumbing part. We have a basic set-up of skimmer and filter falls. We would like to do the plumbing as easy as possible and use our existing pond pump (which is in the skimmer box) and not have to buy a dedicated UV pump. So that will probably mean we also have to plumb in a diverter or something because our pump will pump too fast for the UV. It all sounds so confusing.

Is it true that you can run it just enough to clear the water and then turn it off until the water greens up again? I'm thinking maybe, just maybe, if we get it cleared up good, then I can actually SEE what's in there to vacume out and maybe, just maybe the water will stay clear since the nutrients will be much less? Or am I fooling myself? I'd like to go into this with my eyes wide open and not naive. Are they expensive to run as far as electricity, or just expensive when you buy them and when a bulb needs changing? If you don't run it all the time, do you still have to replace the bulb every year? Ugh. I was feeling pretty knowledgeable about certain things, having learned a lot in the past couple years, and now I feel like a newbie all over again.

Anybody? H E L P !!!

Thanks again to my old friends here. I see a lot of new people have joined. That's great!

Oh, one more thing. My pond tests 0 for ammonia. I know the algae is probably using it all up. SO.....IF we get a UV and it kills all the algae, then IF my biofilter is not large enough (it's just the biofalls filled with Matala pads) and there's not enough plants, then what? Then I'm going to have problems with ammonia? A whole other problem to then deal with? Ugh....................................BTW, all my water parameters are within normal limits. They always are, despite my fluorescent green water. Wish I could splash it on some fancy canvas and call it art. Maybe I could sell it and make enough money to buy the dang UV thingy!

Thanks for listening to me whine once again.

Sandy

 

[MitchM]

UV's are pretty simple, water in and water out, get the proper sized unit for your pond. Electricity is minimal, bulb replacement yearly. Make sure you bring it inside for the winter.

I read in your build thread that you prefer a natural approach, have you considered a bog instead?
It would probably cost less to set up but it would be more labour of course.

Also - your pond doesn't look like it has any berm that would prevent runoff from your yard entering your pond.
If surface water runoff is entering the pond, that's not good.

 

[joesandy1822]

UV's are pretty simple, water in and water out, get the proper sized unit for your pond. Electricity is minimal, bulb replacement yearly. Make sure you bring it inside for the winter.

I read in your build thread that you prefer a natural approach, have you considered a bog instead?
It would probably cost less to set up but it would be more labour of course.

Also - your pond doesn't look like it has any berm that would prevent runoff from your yard entering your pond.
If surface water runoff is entering the pond, that's not good.

Thanks for the reply. Though there is no berm, I have never noticed any runoff. Our surrounding soil is mostly sand and rain, even heavy downpours, seem to soak in immediately.

Yes, I've toyed with the idea of a bog, and some day I would love to have one. Now is just not that day. Right now I just want a quick fix. Sounds so terrible considering I never imagined I'd go this route in a million years. I've seen DIY UV setups. I might do some research. Seems it could save a lot of money.

Thanks again for the suggestions.

Sandy

 

[joesandy1822]

I'm still reading and trying to understand the difference between clarifiers and sterilizers. Also trying to determine how to know how large (how many watts) is necessary. Is it better to go larger than you think you need? I've read one reason why many people are disappointed in the results is that they go too small to begin with. Another problem is if the pump pushes the water too fast.

Probably making this harder than it has to be, but for the life of me I can't seem to picture what this will look like. We have ONE flexible 2" PVC pipe running from our skimmer (which homes our 5,200 gph pump) to the bio falls. That is the extent of our plumbing. The pipe is buried under probably 5" of soil behind the pond under the trees. So I have a couple questions.

I'm assuming you just cut the pipe and plumb in the UV. Simple enough, but that requires digging it up first off. The UV has to be above ground, correct, for maintenance and changing bulbs. So What does that look like? The whole UV thing will be sticking out above ground? Does it have to be fastened to something?

Second problem is our pump flows too fast. We will have to do a bypass somehow. What does that involve? If somebody can show me a picture or diagram of a simple setup (no pressure filters, nothing fancy, just a UV with a bypass plumbed into a single pipe) I'd so much appreciate it. I can't seem to envision what this will look like when finished. If you look at my pond here https://www.gardenpondforum.com/threads/pool-to-pond-2013.12652/page-2 the pipe runs from the skimmer to the falls, behind the pond and slightly under the trees. Where would be a good place to tap in? I don't mind going under the trees for maintenance, and we don't want to be tripping over it because we do walk around the pond frequently.

Here is a diagram I found of basically what I think the plumbing would look like with our setup:

So basically I would leave the UV sticking out of the ground under the trees? I still can't find info about how to install some sort of diverter to slow down the pump flow to the UV.

Anybody? Thank you for your help. I've searched, honestly, and even YouTube has not been much help as far as how to plumb a SIMPLE setup. Most people are gearing it towards aquariums or fancy pond setups with pressure filters and a bunch of stuff we don't have.

 

[MitchM]

Until you mentioned that people have built DIY UV sterilizers, I didn't know that people actually tried that. (poorly and dangerously, too). I call them sterilizers, because they are not filters. They do not filter out anything.
I found one Youtube video of a guy that says he spent $70 on sterilizer parts that would have normally cost about $150 for a properly built unit. What he built is dangerous. He is exposing UV bulbs directly to water, which is not what they were designed for and his only safety factor is a gfci, which themselves can be cheaply made and not work as intended. Is your safety really only worth the difference of a properly designed one - $80? Sometimes watching DIY videos on youtube is like watching an episode of Americas funniest home videos, only worse since your personal safety is at risk.

Even if you use an ultraviolet sterilizer, you will later wind up having to deal with string algae.

In your pond, I see that you are adding phosphate but not removing it. Every time you feed your fish you are adding phosphate to your pond. Phosphate is a one way street. Unless you are removing it, it is staying there and macroalgae is there, happily waiting to use it. If you are feeding your fish, stop feeding them. I have a 6000 gallon pond that I don't feed, and the goldfish and minnows I keep survive quite nicely. Last July I added 20 minnows. By the time winter rolled around I had about 1000 minnows. Goldfish are spawning regularly as well.

I have floating green algae as well, but I view it as giving my fish a safe place to hide and something to eat. The algae comes and goes. It's not a bad thing.

If you want to add a UV sterilizer to your pond, the diagram you posted looks like a good setup, and you should look for a used one on a place like craigslist. Buy an over sized one. You could build a basic 2X4 box with treated plywood sides to mount the unit in. The ball valve in your diagram allows you to control the flow to the UV unit.

UV sterilizers can be effective, I use them for my indoor aquariums, but they are not a cure all. Understand their limitations. The phosphate will still be there.

 

[crsublette]

Yeah, I think the ducks are likely continually fertilizing your pond. Most likely... you need even more plants or use fishing line criss crossed across the pond to discourage the ducks... I bet a bog that is jam packed with plants would help out tremendously...

Looks like you have a nice yard...another alternative could be to use your nutrient rich pond water to irrigate your lawn, rather than your sprinkler system... using a lawn sprinkler transfer pump (these can be expensive). or just a basic slow fountain pump that slowly pushes water into a slotted pvc pipe that you occasionally move around on the lawn... As the fountain pump slowly irrigates the lawn, you are slowly replenishing the water back into the pond from a clean water source. This is called a "flow through" water change system and, even at just a low percentage rate, can amount to be a big water change, done safely, over an extended period time.


UV is a quick fix for floating algae, but, as Mitch mentioned, the nutrients will still be there and likely the UV device, as a result of killing the floating algae, will allow a huge nutrient buildup to encourage a massive string algae explosion, which your fish might feed on the string algae if they are hungry enough.

UV or not UV might be a good read for you... Be sure to checkout the hyperlinks in it as well... Any UV can be a sterilizer and any UV can be a clarifier... All depends on the flow rate and light's intensity to break through the organism to irradiate it. I have heard some folk have good luck with the 55 watt Jebao (as mentioned in the UV or not UV thread).

Your diagram 2 is a perfect example of how the install would happen... However, for you, I think the best spot might be near your Filter Falls... So... All you would have to do is..
a) install a " T " to the pipe that connects to your Filter Falls right around there closest to your Filter Falls...
b) Add 2 valves to this " T "... 1 valve that controls the water to the Filter Falls... 1 valve that controls the water to the UV device..
c) Water from the UV device simply dumps, over the top, right back into the Filter Falls...

Now... since everything is buried... you would need access to the valves... You could place a sprinkler irrigation box where the valves will be so you can have easy access to them. From looking at this pic of the Filter Falls... so you can maintain easy access to the UV device... you might could use another irrigation box or some other container for the UV so to hide it under the rocks... and then simply have the pipe from the UV device come out and, over the top, dump right back into the Filter Falls... and... to test the flow rate out of the UV device, simply connect a garden hose to this dump out so to fill up a 5 gallon bucket and time how long it takes to put 5 gallons into the bucket.


Hope this helps... I understand how aggravating it is... Unfortunately, there is much in keeping a pond that is about making compromises....

 

[joesandy1822]

Th

Until you mentioned that people have built DIY UV sterilizers, I didn't know that people actually tried that. (poorly and dangerously, too). I call them sterilizers, because they are not filters. They do not filter out anything.
I found one Youtube video of a guy that says he spent $70 on sterilizer parts that would have normally cost about $150 for a properly built unit. What he built is dangerous. He is exposing UV bulbs directly to water, which is not what they were designed for and his only safety factor is a gfci, which themselves can be cheaply made and not work as intended. Is your safety really only worth the difference of a properly designed one - $80? Sometimes watching DIY videos on youtube is like watching an episode of Americas funniest home videos, only worse since your personal safety is at risk.

Even if you use an ultraviolet sterilizer, you will later wind up having to deal with string algae.

In your pond, I see that you are adding phosphate but not removing it. Every time you feed your fish you are adding phosphate to your pond. Phosphate is a one way street. Unless you are removing it, it is staying there and macroalgae is there, happily waiting to use it. If you are feeding your fish, stop feeding them. I have a 6000 gallon pond that I don't feed, and the goldfish and minnows I keep survive quite nicely. Last July I added 20 minnows. By the time winter rolled around I had about 1000 minnows. Goldfish are spawning regularly as well.

I have floating green algae as well, but I view it as giving my fish a safe place to hide and something to eat. The algae comes and goes. It's not a bad thing.

If you want to add a UV sterilizer to your pond, the diagram you posted looks like a good setup, and you should look for a used one on a place like craigslist. Buy an over sized one. You could build a basic 2X4 box with treated plywood sides to mount the unit in. The ball valve in your diagram allows you to control the flow to the UV unit.

UV sterilizers can be effective, I use them for my indoor aquariums, but they are not a cure all. Understand their limitations. The phosphate will still be there.

Thanks very much for the input! I'm still absorbing everything you said. I will probably have to start doing more water changes to keep up with the ducks. We only feed the fish about once a week, but as you said, it adds up. Some day I WILL build a bog!

 

[joesandy1822]

Than

Yeah, I think the ducks are likely continually fertilizing your pond. Most likely... you need even more plants or use fishing line criss crossed across the pond to discourage the ducks... I bet a bog that is jam packed with plants would help out tremendously...

Looks like you have a nice yard...another alternative could be to use your nutrient rich pond water to irrigate your lawn, rather than your sprinkler system... using a lawn sprinkler transfer pump (these can be expensive). or just a basic slow fountain pump that slowly pushes water into a slotted pvc pipe that you occasionally move around on the lawn... As the fountain pump slowly irrigates the lawn, you are slowly replenishing the water back into the pond from a clean water source. This is called a "flow through" water change system and, even at just a low percentage rate, can amount to be a big water change, done safely, over an extended period time.


UV is a quick fix for floating algae, but, as Mitch mentioned, the nutrients will still be there and likely the UV device, as a result of killing the floating algae, will allow a huge nutrient buildup to encourage a massive string algae explosion, which your fish might feed on the string algae if they are hungry enough.

UV or not UV might be a good read for you... Be sure to checkout the hyperlinks in it as well... Any UV can be a sterilizer and any UV can be a clarifier... All depends on the flow rate and light's intensity to break through the organism to irradiate it. I have heard some folk have good luck with the 55 watt Jebao (as mentioned in the UV or not UV thread).

Your diagram 2 is a perfect example of how the install would happen... However, for you, I think the best spot might be near your Filter Falls... So... All you would have to do is..
a) install a " T " to the pipe that connects to your Filter Falls right around there closest to your Filter Falls...
b) Add 2 valves to this " T "... 1 valve that controls the water to the Filter Falls... 1 valve that controls the water to the UV device..
c) Water from the UV device simply dumps, over the top, right back into the Filter Falls...

Now... since everything is buried... you would need access to the valves... You could place a sprinkler irrigation box where the valves will be so you can have easy access to them. From looking at this pic of the Filter Falls... so you can maintain easy access to the UV device... you might could use another irrigation box or some other container for the UV so to hide it under the rocks... and then simply have the pipe from the UV device come out and, over the top, dump right back into the Filter Falls... and... to test the flow rate out of the UV device, simply connect a garden hose to this dump out so to fill up a 5 gallon bucket and time how long it takes to put 5 gallons into the bucket.


Hope this helps... I understand how aggravating it is... Unfortunately, there is much in keeping a pond that is about making compromises....

Thanks again for the info! Still trying to absorb it all.

Have given up on keeping the ducks away. Will do more water changes I guess. We enjoy them and I don't like constantly worrying about it. The fishing line only deterred them for a short time.

Our yard only looks nice in the photos maybe. It's country grass full of weeds, and we don't have a sprinkler system. My goal is to eventually eliminate most of the lawn and plant native wildflowers and grasses and get certified by the National Wildlife Federation as a wildlife habitat. AND one day soon, I will build a big bog.

I think we will just purchase a separate pump and forget tapping into the main line.

I am still confused about something though. If the UV kills the single cell algae, and the algae was actually using up the nutrients (hence my 0 reading for ammonia), will I then have problems with ammonia?? Am I trading one problem for another?? Sheesh. I have a headache.

Thanks again.

Sandy

 

[crsublette]

I am still confused about something though. If the UV kills the single cell algae, and the algae was actually using up the nutrients (hence my 0 reading for ammonia), will I then have problems with ammonia?? Am I trading one problem for another?? Sheesh. I have a headache.

Bingo... there are always trade-offs and compromises...

 

[joesandy1822]

Bingo... there are always trade-offs and compromises...

Ok....well my situation is not unique in any way. Most, if not all, pond hobbyists who get a UV do so to clear green "pea soup" water. So what then? If the algae was responsible for no ammonia readings, and you kill the algae, then what? Exactly what will I have to do to combat that? A larger biofilter? A bog? Some would say if I had a bog, I would not get green water. Some say that is not the case. Anybody out there who uses a UV, please let me know what I can expect because I AM getting one soon and I want to know what I am getting myself into regarding water quality. I've not really read on here or anywhere else anything that said getting a UV sterilizer/clarifier actually made problems for them in regards to water quality. Maybe I just haven't looked hard enough?

Thanks.

 

[MitchM]

Algae is not the main reason why ponds have no ammonia. Nitrifying bacteria are the main reason.
Algae will become visible when nutrient levels exceed what the nitrifying bacteria isn't able to process fast enough.
Water conditions in a pond are constantly changing. Nutrient levels, PH and temperature are always fluctuating so the pond is constantly trying to find a balance.

The biggest problem we have is that we try to put too many fish in too small of a water body - then we put extra food in the water on top of that. The bacteria are not able to reproduce fast enough, or maintain a high enough population to keep up with what we put in there.
To compensate, we need to add various filters in order keep good enough water quality for the fish to survive.

If you do add a UV unit, it will clear up the appearance of the water and more ammonia may become available for a higher bacteria population. (that's not a bad thing)
When the UV is running, it will kill the floating algae (and anything else that passes through). That dead algae will fall to the bottom of the pond or be removed by your filter system.
If the dead algae remains on the bottom of the pond, it will decompose and release more nutrients, so it is important that you increase your filtering capacity as well.

The best thing any of us can do for our ponds is to reduce how many fish we put into them, reduce the feedings, increase filtration, aeration and water movement.
Algae will step in where we fall short.

 

[MitchM]

Are you going to be building your own UV unit?

 

[joesandy1822]

Are you going to be building your own UV unit?

Um, N O ! I want to live a few more years I think. I am definitely a do-it-yourself type person, but that is going a bit far even for me.

My plan is to get a Jebao 55 watt, put it on a dedicated 1000gph pump, and see what happens. I know it is not an expensive UV, but it got good reviews and there is another member here who is very happy with theirs. To me it is worth trying. I just need to figure out if I want to pay nearly $1 a foot for flexible PVC or what type of hose I'm gonna use. I'm not up for having to dig a bunch of pipe in ground, and would like it to be completely removable at the end of fall to store indoors. How to do this without tripping over the pipe is what I have to figure out. I could have most of the pipe IN the pond, but it still has to exit two places (intake and output of the UV). Maybe I can just bury it where it would cross the walking path.

I will try to do more water changes. We really only feed the fish once a week (for enjoyment). May or may not stop doing that. I really can't tell how many fish I have right now due to the green water. I suspect a lot of fry survived. They seem to like green water. I just read an interesting article about that here: http://www.raingarden.us/green_water.htm It almost makes me feel guilty for wanting clear water, but I would really like to see the fish!

Thanks for your input! I appreciate it very much.

Sandy

 

[Mucky_Waters]

It's true that algae can absorb and feed on ammonia directly as a nutrient, but algae also absorbs and feeds on nitrates which are the end byproduct of bio-filtration. Nitrates are basically nitrogen fertilizer, which can feed both pond plants and algae. Fortunately fish can tolerate fairly high levels of nitrates, but at higher levels they can still have a negative effect on fish. So what do you do to get rid of excess nitrates that build up in your pond water? Well having a lot of pond plants that have their roots directly in the water can help absorb nitrates. But as already mentioned, water changes are really important, and the main way most aquarium and koi only enthusiast control nitrates in their ponds and aquariums. Routine water changes can reduce ammonia, reduce nitrites, reduce nitrates, reduce phosphates, reduce free floating (peas soup) algae, and also reduce organic waste and material that would eventually convert to all of the above. It can also replenish minerals and trace elements that are necessary to the health of your pond.
Another thing to keep in mind is although UV units will help kill free floating algae, the nutrients that the algae absorbed will eventually be released back into the pond water as the algae cells die and decomposes. The only way to actually get those nutrients out of the water is to either filter out the dead algae or remove it through water changes, or preferable both. However to filter out the dead algae you will need a fairly fine filter media. Quilt batting is something a lot of people use, but there are other fine filters that will also work like sand filters.
One other point regarding water changes. It is a chore that many people with ponds often ignore because in large ponds it can be a big job that requires dealing with large volumes of water, especially if their source water is chlorinated. However there is an easier way to accomplish water changes without it being a chore at all, and that is by using the drip water change method. In fact this is the preferred method because when it is set up properly it is safer and everything is accomplished automatically with no effort on your part, except to periodically check and make sure the drip is still working and hasn't somehow been plugged or something. Really worth looking into.

 

[Mucky_Waters]

Regarding drip water change system,,, watch this video.