Fish tank / pond substrate material

[Shawn Waggoner]

I am starting a new aquaponics systems and using an existing 125 gallon pond we had as the fish tank. We had goldfish and turtle in there successfully for several years. We drain most of the water and cleaned it up pretty good as well as removed the goldfish and turtle before starting the new aquaponics setup.

My question is, on the bottom of the pond, we had a covered with a couple of inches of river rock. We found this very helpful for filtration when it was just a 'pond'. Now that it is a fish tank, should we leave the rock there or remove it? My concern is it acts like a filtration layer and maybe processing water there and taking away from the grow beds. It may not hurt anything at all. We just don't know.

It's nice to look at, I just want to make sure it's not hurting anything by having it in there. Thanks in advance.

[Melvin Avery]

Hey Shawn INHO would leave the pond the way it is and just add fish.  Would guess that it is cycled and I believe that if you mess with it you`ll loose some of the good bacteria.  That system looks great. 

Later

Mel

[Glenn]

Sharp edged gravel/stones could cause skin abrasion or lesions leading to infection etc.  This doesn't seem as much of a concern for docile fish like gold fish or tougher skinned fish like catfish.