Simple filtration for large stock tank

[igalysh]

I have a question about filtering a 800 gallon stock tank. I have 5 goldfish and some minnows. I've researched filtration for ponds and all seem too large but those ponds have a lot of fish. I don't plan on adding more fish but do want to add more plants in the future. I bought an in pond filter that includes a UV light and that has kept the water clear but hasn't stopped the string algae and needs constant maintenance. I also had the largest CO-OP sponge filter with an airline. I was thinking with my low count of fish, I don't need such large filtration. With such a small number of fish for 800 gallons, would the largest CO-OP sponge filter and power head combo be enough? I think an air pump sponge filter wasn't circulating the water enough to get good filtration. I am also experimenting with the K1 media in the 2 liter soda bottle but am concerned that it won't circulate the water enough to filter well enough.

I have two other tanks with sponge filters and upgraded them with power heads and the water in both tanks got very clear . Both tanks are planted with a few small fish. I was thinking of replicating the same with the stock tank.

And this year with the 5 goldfish, my water lettuce stayed small. Do goldfish like to nibble on the roots?

Any suggestions?

[Dwayne Brown]

First off yes goldfish like to nibble on the roots )goldfish like all plant matter is seems). 

Second one of the large coop sponge filters in somewhere near enough. I would get at least 4 or 5 ones going at the same time. I don't have experience with powerheads so I can't comment on that. 

[lefty o]

at 800 gallons, id probably consider a canister filter. not to say other methods wont work, that would just be my choice.

[igalysh]

I'm going to experiment. I have two of the large sponge filters stacked with a CO-OP power head pulling water through the sponges and the K1 media tumbling in a 2 liter bottle. I'll remove the all-in-one pond filter with the UV light and see what happens. One of the sponge filters has been in the tank all year so it is well established. The K1 media started tumbling after a day in the tank.

I looked at pond canister filters. They use sponges and a little bit of bio-media, some kind of bio-balls. I figure the sponge filters with a power head will work similarly. The 5 gold fish were bought from the Petsmart as feeder fish. They have grown nicely and are quite active.

I have been reading this site about filtration. https://aquariumscience.org/