Install a Bigger Filter in A Koi Pond

LESLIE: Audra in New York has a question about a koi pond. Tell us what’s going on.

AUDRA: Hi. I have a 2,000-gallon koi pond with a small filter on it; have some fish in there. But I’m really having a hard time keeping the algae down, so I wanted to know how to treat it without killing my fish.

LESLIE: Which is always a good question. (chuckles)

TOM: So hard to explain that to the kids. (Audra chuckles)

LESLIE: Oh. I think what’s important here is – you may have even answered this yourself when you said you have a 2,000-gallon koi pond and a small filter. Now, the reason why you keep getting algae forming in the koi pond is algae forms when the nutrient levels get too high in your koi pond, causing the algae to bloom. And the nutrients come from two places; one being the koi food and then the second, of course, being the koi waste themselves. You know, they have to go to the bathroom and they have to eat.

So what happens is the filter acts as the remover of the koi waste and then the food residue from the water to keep those nutrient levels sort of normal or low. Now, when the filter is not doing its job properly, you’re going to get a higher level of the nutrients and then you’re going to see the algae blooming. So what you need to do is you need to make sure that you have an appropriately-sized filter for the pond size, which might not be the right thing.

And if you’re in the market for a new filter anyway – if you find out that it’s not properly sized for the amount of fish, for the amount of water, whatever it might be – you want to make sure that you’ve got a mechanical filter, which is going to remove the waste and the debris and then get it sort of trapped in the fiber; then you want to make sure that the filter itself has an area that can manage chemical filtration so that you can add something to the filter that will help to adjust the levels in the pond.

And then some filters are even available with a UV light, which is great because what that’ll do is that’ll kill any sort of floating algae or bacteria before it even enters the main filter. So all of these three parts sort of work together to help you create a clear environment because a koi pond – I mean they’re gorgeous and they’re supposed to really reflect all the hard work that you put into it and if you can’t sort of manage the levels, it’s just going to look not so great.

AUDRA: I appreciate your help.

LESLIE: Oh, it’s our pleasure.

TOM: Thanks so much for calling us at 888-MONEY-PIT.