But Cecil I want to go from pond to a 300 gal or so fish tank then to the grow beds then back to the pond.
O.K. that's different. My bad, I read you were using just straight pond water with no fish in the barn. So your pond water will be your make up water?
The fish tank will provide the nitrates you need as the fish are concentrated. However you will still need some form of biofiltration to convert ammonia produced by the fish to nitrites and then nitrates,and as back up when you harvest your plants.
Does that make sense?
How big was your pond? Unless it's quite large your discharge will make your pond water ripe for algae and macrophyte growth. Additionally you run the risk of introducing parasites and pathogens to your concentrated tank fish if you use straight pond water, which can go crazy in a tank of concentrated fish. However if you do use the pond water for make up water you could use a UV filter or chlorinate it and then dechlorinate the water via aeration before adding it to the fish.
Not trying to be a downer just telling it like it is.
BTW are you thinking raft culture, media, NFT, or all of the above?
