Backyard Aquaponics
A place to discuss aquaponics

I am look at setting up small aquaponic system. I am looking at a tray 4’X 8’ X6.5” the tray is made of ABS plastic. I have several questions.
Is it safe to use ABS Plastic in aquaponics?
Second, the tray is only 6.5” is it deep enough?
120 gallon of media will allow me to have around maximum of 24 lbs of fish?

No issues with ABS that I know of. I grudgingly use PVC when I can't use HDPE, but it's because of the impact of its production and disposal, not because it'll harm fish or bacteria. I'd rather use ABS piping to tell the truth.

Yes, 6.5 inches is deep enough to get filtration, but be aware you will have to clean it out of roots and muck that would normally not be an issue with a deeper (18" or more) growbed. Actually sounds like a nice tray you found. If you get some deeper gravel to flood and drain later, this could be a sweet raft tank. Need clean, solids-free water for that though.

I'd start with 18-22 small fish and harvest them by 1 lb. this first time around. See if you can get more growbed working, I think you will (most people start looking to expand pretty soon after they get going).

You did not mention how much fish tank water the fish will have... I may change my answer depending on what you're planning.

And more advice will soon be added. Take it all in, enjoy all that you are about to learn. I have picked up a lot of practical know-how in plumbing, chemistry, electricity, plumbing, biology, hydraulics and especially plumbing since deciding to improve my backyard the Aquaponics way.

Welcome to one of the friendliest, funniest, most active corners of the Net!

Post a picture of this ABS tray, I'd like a look.

Rick

Sminfiddle:
No tray as of yet just doing the planning. Do you think I should do a raft system instead of a meadia system? I could make a bio filter out of a couple of 55 gallon drums. As to the size of the fish tank, 100 gallons to 150 gallons, with a sump of at least the same size.

Such a tray could be used but I would strongly recommend going for deeper grow beds for a flood and drain media system.
I can't really commend on a raft system as I've never really done a pure raft system and what small amount of rafts I've added to existing systems were not all that effective for me as my system isn't designed that way. I am a big supporter of flood and drain media systems with deep grow beds. I've become rather partial to Rubbermade stock tanks for grow beds. Especially the 100 gallon ones for grow beds as all I need to do is set them up on blocks instead of building stands or anything like that.

Yes, perhaps 120 gallons of flood and drain grow bed could support up to 24 lb of fish but for the first season I would definitely recommend less. 18 small fish would be a good start for the first season. I also strongly recommend fishless cycling the system to get the bio-filter bacteria colonies established before adding fish but that is just me (search Pee Ponics if you like.)

Good Luck in your design phase.
Welcome to the addiction, there is no escape

I am not marred to using hydroponic trays. I just want something easy.
Rubbermaid 100 gallon tubs sounds good to me. I will have to take a good look at your tread.

It's a long one. I didn't come around the the rubbermades till lately. They are on sale at the moment I think.

Rubbermaids rock! I recommend strongly (see my car there to the left).
Yes the 100-gallons are on sale nation wide, wow that doesn't happen often.

Edit, hope it takes: And no, don't do raft or (NFT) until you have some media in place and are comfortable with managing that.

Rick

Do you folks use the drains that are already installed in the Rubbermaid tubs or do install a new one in the bottom of the tubs?

If I fill a 100 Gallon Rubbermaid tub with Hydroton how much water with the tub hold?

I usually install a 1 1/2" uniseal in the front of the tank to one side or the other of the installed plug. That installed plug is actually a 1 1/4" fitting and it really only works to hook up a fitting on the outside. It doesn't make for an easy way to hook up an inside stand pipe. I use the 1 1/2" uniseal and put a bit of pipe through and use an elbow on the inside. Then I can stick a piece of pipe cut to the desired length inside as a stand pipe and drill how ever many holes just above where it would fit into the elbow that I need. Sure this will leave a few inches of water in the bottom of the tank but it is a 24" deep bed so that is all fine.

Other people will install fittings through the bottom between the bracing. I like the ones on the front for easy access and not having to fiddle with making sure the blocks are not in the way of the plumbing.

I second TCL's method for the 100's. You don't want an inaccessible fitting!
Might be wise just to silicone completely over that drain plug (on the inside) if there's any chance of the tub freezing. The expansion/contraction can generate a leak there. Hasn't happened in an AP system to date, but the preventative step is so easy.

40 to 50 gallons would be my rough estimate. I can't afford that much Hydroton but some of the water goes into the medium so it may be more water than when using nonporous gravel. Rupert may have actual data.

Rick

To flood a bed with water after it is filled with media, we usually estimate an average of 40%. However, if you are figuring your sump tank size, I recommend figuring that you need 50% of the grow beds volume to flood it, just so you have enough sump capacity.