Problem with new pond & keeping submersible pump clear

9 years ago

I recently built a small pond that is 11 ft. dia. and 3.5 ft. deep in the center. Just guessing , that is maybe 1200 gallons? I bought a Totalpond submersible pump with 9 W UV and supposedly 950 GPH. I home-brewed a filter with a Rubbermaid box, three bags of charcoal, and a dozen "bio-balls", topped off with several inches of fiberglass insulation.

Well, the pond is staying green, and when I measured to actual flow rate, its only pumping around 300 GPH! And that's with the intake slots clear, and there is a total head of only about 1 foot (submersible is near the shallow edge)! Seems like I got ripped off by false advertising on the product packaging. I am thinking also that 9W is not nearly enough UV power to do much for killing the algae. The other big problem is that there is no covering over the pond and I guess the wind blows lots of dirt and vegetation debris into the pond. However there are no tree limbs directly over it, but there are trees very close by. So in only one to two days, the slots on the pump get clogged up. I don't have a lot of free time, and so this is a big problem to have to lift the pump out of the pond almost daily and clear it!! I am thinking I have to upgrade both the pump and the home-made filter. to keep the water clear. But if I get a bigger submersible I will still have the same problem of it getting clogged up. Is there something I can screen the submersible with that will help keep debris from clogging the pump? Recommendations for submersible and filter upgrade so that the pond will be low maintenance?

Also, I put three Koi fish in, about 3-4 inch long. Their behavior seems odd....they are always down at the very bottom, even now that the hot summer weather is over. They do not even come up to feed when I put food in for them. Whats' up with this?

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Comments (4)

joe009
9 years ago
put your pump in a mesh planting basket and fill the basket with lava rock.that will keep the pump from clogging.if you are getting only 300 gph.the flow thru the uv is not enough.look at the uv or go on line to find what is the max flow thru your uv. too little or too much and the uv wont work right.if you are looking for a new pump the fishmate series is a good pump with higher head pressure than most.an external pump and filter is the best way to go
chas045
9 years ago
I guess that if your pond depth is really 3.5' that your volume may be correct. In any case, 900gph is way low for the generally suggested ratio of flow to pond volume. BTW, I have an auxillary pond that has no flow. It can be a total mess of muddy water after a big rush of accumulation from our French Drain. However, this crud will precipitate and this catch basin will become completely clear, again with no pump!

I have been very lucky and never had pea soup type issues. I am assuming that this is what you are referring to and not just some string algae, which is a good thing anyway. You failed to indicate your location or garden zone. It may be useful information. I hear that ponds without much plant cover are more likely to get algae problems. I suppose hotter brighter conditions increase the problem. My aux. pond (without any flow) is in the woods with minimal sunlight.

There are plenty of in pond pumps that work fine. I don't actually understand where your crud that restricts flow is collecting. I have a 2500gph pump contained inside its own overall slitted case. I remove leaves and other crud that get sucked to the surface every few months. Perhaps your pump is so close to the surface that it catches most of your leaves? Perhaps at the bottom instead, right where leaves fall? BTW, the bottom is not the right place for a pump because a big plumbing leak/break will drain the pond.
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akarinz
9 years ago
My koi stay at the bottom for two reasons...when the weather starts cooling off, they stop eating and just linger at the bottom. If they are frightened they stay at the bottom for a couple of days. I could always tell when the heron had been there. Now my redone pond is four feet deep, so I don't have to worry about it. Do you have any plant material in the pond, so they can feel safe?
jimigunne98
Original Author
9 years ago
there aren't predators hanging around and I have not put any plant in it as I heard that Koi will eat just about any/all plants. Today for the first time I did see them coming up from the very bottom/center to about half way to perimeter of pond where it is only 1 ft. deep or so, so that is hopeful. The original pump is no good, pumping only 300GPH max with the valve wide open, and I found the bulb burned out--- so I ordered a Totalpond 1200 GPH. submersible pump. Also have started building a bigger filter in a 32 gal Wal Mart trash can. I got a TotalPond mesh bag and put submersible inside it, this helps a lot to keep the intake slots clear of debris. Many thanks to you guys who responded.