Backyard Aquaponics
A place to discuss aquaponics

Can you have TOO MUCH Fish Fetal matter in you lower tank to pump to your flood and drain grow bed ?? Suppose you did not have to worry about the fish ,in the tank and the effect on them?? This is a serious question ,I am asking because I back Back flush my mechanical Sand and Gravel filter on my pond and expell that liquid to other uses out side the pond ,and I do it every week 50 -75 gals .just suppose it went to the bottom tank w/o fish and was pumped up to a flood and drain system in upper grow beds.with worms and recharged every week ,excess over flows for other growing uses.
Your opinions and comments requested !! Thanks.

Hi Ulerilina,

Welcome!

I have read quite a few articles by knowledgeable people that suggest fish effluent directly in the grow bed poses a health risk when eating the vegetables/herbs. Personally, I've always thought that was germaphobe approach to farming!

My systems send the solid waste up from the fish tanks and into the grow beds. I've got red wriggler worms to eat what they can but the beds do tend to get a little clogged with sediment. That's less of an issue than the tax on the pumps & water lines. Every few weeks a gelatinous build up (concentrated solids) accumulates and I need to snake the hose (1/2") with wire & take apart the pumps. That's about the biggest problem I've experienced with having the solids flow through the systems. Moving in a couple months, I'm going to upgrade to a larger system with the mechanical pump in a sump tank. That'll have the fish tank elevated above a solids filter, running into the grow beds & down to the sump. Then I can still collect solids for fertilizer without worrying about the extra maintenance.

All the excess that doesn't find its way to the worms gets dried out, and ground up. That stuff is great for the soil garden!


At the rate you describe, I doubt you would need to recharge your grow beds' water as often as you are cleaning your filter. At least not with that much water. You might consider doing both a couple of grow beds and storing the rest of the water to use on a soil garden. Maybe a floating raft tank for leafy greens too? Those need as few solids as possible, though, for root health.

I bet you could run the water out through a course filter to collect solids while you are back flushing to dry solids for fertalizer/additive to compost. It's all good stuff so wherever you can get it to your vegetables will make them happy!

-Nick