Backyard Aquaponics
A place to discuss aquaponics

Ok, so I am going to start a system soon and have a few questions, but first a little about my plan so far.

I am planning on going with a 100 gallon (378+/- L) FT, starting with 2-50 gal GBs. 2 more GBs to be added later probably.

I am hoping to stock channel cats, or maybe rainbow trout.

I have read the the volume ratio to shoot for is 2:1 GB:FT

I believe I read that this is the actual volume of the bed, and not the volume of water it take to fill it, correct?

I read that hydroton displaces roughly 60% of the growbed volume, some one said their gravel was about the same. If this is indeed the case and you do have the 2:1 ration you would have something like 80%of your FT water in the beds if both flood at the same time. A sump would fix this, but would it need to be the same size as the FT?

My plan was to put the extra tank (whatever size you guys and gals recommend) next to the FT with a standpipe overflow in the center of the FT (like the bell siphon without the cap so water is actually coming from the bottom of the tank) so the FT water level will remain fairly constant and not drop below the standpipe. The water then travels to the sump where it is picked up by the pump and sent to the GBs. Then it auto siphons back to the FT.

Sound like a plan?

Also, when "cycling" the system to establish the nitrogen cycle, do you have to put something in it, or does the bacteria just appear? I know some have said using media from someone elses system, or aquaium would speed it up, but is not neccessary.

I'm sure I come up with more questions, and when I do I'll try to keep them all in the same location.

Thanks a bunch,
Steve

Hi Clovis, looks like your reading has put you pretty well on the mark...

Many people seed their systems at startup time by squeezing the gunk from an existing aquarium filter and/or water & gravel from an aquarium....

This provides a fast track development of the bacterial colony.... but have no fear.... nature will provide from scratch if required ....

Might pay to read up on the Rainbow Trout .... think you'll find they may have different temperature, flow and DO requirements to the catfish.

Either as Rope says or use fish, it needs something to provide ammonia to start off the cycle.

The 2:1 ratio is the optimum but many of us have GB area to FT of 1:1, this ratio is used to calculate the maximum stocking density (then stay below it )

The GB volume is calculated on the size of bed itself
e.g. 2m * 1m * 300mm (6'*3'*1') = 600 litres (this is only an approximation )

Initial figures show that the displacement is around 60% but as the system matures, roots and stuff start to use up some of this space - it is a good idea to calculate on 60% then you have a good safety margin

Clovis - Les, MF and myself use a system similar to what you describe but we pump from sump to fish tank and them gravity feed water that flows over standpipe to the grow-beds. Is better that way because the poo from the tanks goes straight to grow-beds where water is filtered of solids.

See a summary of my system HERE

I was thinking maybe catfish in summer, and trout in winter, But yes I do plan on doing some more research on it.

Yes I remember read about your system, but how would that work if the FT was buried in the ground?

Welcome Clovis:
Doing it pump->fish->bed->sump only works if the beds and sump both can be arranged to be lower than the FT. I am running my system pump->bed->fish->sump for that reason. The downside like VB says is that the solids build up in the sump if the pump doesn't get hold of them.

For the drain you can have a hole in the bottom of the FT as you describe, or just make an elbow using a tee with the drain pipe going out the FT at water level, so that the drain can pick up solids from the bottom of the FT. EB in one of his systems and I are using that kind of drain elbow thing.