Big Bio filter possibility looking for ideas. I

[Akjon]

Year 2 of ponding Ihave a 600 gallon pond here in Alaska with a water fall stream. 2 baby koi’s some feeder goldfish. I was able to get these 200 gallon fish totes. One I plan on using for water changes to let chlorine dissipate and warm up. Faucet water comes out at 50° year round. The second I’m going to place at the top of the water fall and make a bio filter. I’ve seen many plans for 50 gallon drums but nothing this size. Filling 200 gallons with media seem expensive. ALASKA doesn’t always have same options. Things I can get are gravel pea gravel. There is a lot of nylon fishing nets that I could get cheap and would take up a bunch of space. Is there a rule for ratio on types of media. Thanks in advance

 

[Lisak1]

If a bog filter is your goal (plants growing in the top) then I'd stick to gravel or rocks. You can fill the bottom with largish rocks and then gradually use the smaller gravel on top.

 

[j.w]

@Akjon

 

[mgmine]

Here is mine 275 gallons

 

[Akjon]

Thanks perfect I’ll give this a try