Backyard Aquaponics
A place to discuss aquaponics

I have a 150 Gallon tank. I'd like to have about 30 - 40 tilapia. How many grow beds would be recommended for this assuming about 50 gallon grow beds?

As many as you can fit.

seriously though, minimum 3 beds. Up to 6.
then if you can fit more, get another 150Gal tank

Agree with Kuda there. 3 grow beds minimum.

Quick rule of thumb. 6 lb of fish (grown out size) per 25 gallons of grow bed provided you have enough water to go around. How big do you intend to grow the tilapia? If you will be growing them to about 1 lb each, 36 tilapia in 150 gallons of water with 3 of those 50 gallon grow beds. Even better, get a second 150 gallon tank to use as a sump tank and do a CHIFT PIST system and then you can have 6 grow beds and not run your fish tank dry when you flood all the grow beds.

It's OK to have only 1 or 2 GB, just if you do, you can only have 1/3 or 2/3 the amount of fish.

So if 1 GB, then usable water in your tank is 25-50 Gal. So you can stock 6 - 12 lb of (grown out size) fish.

6500L pond... how many fish and GBs would you run?

Steve I have 2 x 3000lt tanks with about 5000lt's of water and have 2 BYAP 500lt GB's, but will keep down to around 50 trout, with Marron and exotics in the other tank probably not enough but we will see, forum member Rick has 3000lt tank and 1000lt sump with 6 GB's which have come to life since putting in trout, I think he could turn 1 or 2 off for a while. So as above, depends how many fish, but is a formula posted in forum, that some when will no about that rates KG of fish to GB area

6500 litres.
large (joel type) GBs are about 600l so 11 - 22 GB
half barrel GBs are about 100l so 65 - 130 GB

fish would be 3kg/100l max, so 200 kg of fish. ABSOLUTE MAXIMUM and probably too much for a beginner.
eating fish @ 600 - 800g means 250 - 300 odd fish.

in time you may be able to stock more, with experience and practise.

22 GB's man you would want a big pocket

Yah, My system will support 22... I have 10, only installed 6... money's holding me back from having bought more...

Ok I'm going with 3 grow beds, but a new question I have is how big of a pump? I would like to just use one pump if possible. I'll have the grow beds all auto siphon.

Thanks

Brandon depends on size of GB's I suppose but if you stick with 50 Gallon GB's and have a 150 gallon tank you will need a sump as you will lose around half your tank water to GB's when pumping, but you need to at least double your pump capacity IE at least 300 gallon per hour, but then depends on head height, if your head height is 5 foot then you need a pump that will pump 300 GPH at 5 foot head so possibly 600 - 900 GPH pump, you can put a tap on your line coming out of pump and release excess water back into the tank, also aides in aeration, if your planning on expanding in the future then get a bigger pump, pump can never be to big and as mentioned you can always regulate how much water is going to GB's

In my large CHIFT PIST system I'm planning to have a 1000 litre IBC fish tank, another IBC as a sump with only around 500 to 600 litres in it (or should I just fill it to 1000 litres), and 10 half blue barrels as grow beds (so 1000 litres of grow beds). Are these ratios reasonable? and if so what sort of fish (Trout) quantities and sizes can I expect to go upto?
Taz.

Hi Taz

3 kilos of fish per 100 litres of gravel so in your case 30kilos of fish = 60 odd trout at 1/2 kilo each or 30 trout at 1 kilo. Up to you how big you want them.

On the sump issue I would guess that 1000 litres of grow beds would only hold about 400 odd litres of water if they are all full, so no need to fill the sump right up. However more water gives more temperature stability so filling it up might be a good idea.

Thanks Nocky,

I'm not exactly sure I understand the part about putting a tap on my line to regulate how much water goes to the GB. If I got a bigger pump would I just let it flow to all of the grow beds and then have it open ended back to the fish tank or sump however I end up configuring it? Or would I actually put a valve on the ouput line and slow the water output?

Hmm actually I guess I could just have the pump output connect to a pvc Y and have 2 valves on it and one end go back to the tank and the other to the GB and basically have the tank one full open and the GB partially open if I need to slow the flow to the GB.

What do you think? I had not really thought about the fact that I'll need a sump to maintain the water levels.. My GBs are going to be higher than my fish tank so I guess what I'll do is pump from the fish tank to the grow beds (and back to FT as per my valve operation above) and have the grow beds auto siphon into the sump and have the sump just overflow back into the fish tank. Does that sound about right?