Backyard Aquaponics
A place to discuss aquaponics

I just found this on the side of the road for free! Its a little beat up, has a few cracks in the bottom, small section of the rim is broken off, but I'm relieved to finally have a large tank for the fish!

(this is just a stock photo, not of mine....)



So I spent a good 10 hours yesterday digging a hole in the ground to put this thing into... I'm so freakin sore, I still have another 4-6" more to dig out before I can put it in the ground

Totally jealous did you check for leaks?

it may leak a little through the bottom cracks, but I dont think it will leak much. I'm pretty sure I will loose more to evaporation than through the cracks.

It also has a big chunk missing from one side along the top. But it will be in the ground, so I will use some pond liner plastic to help keep the water in and it should be just fine.

Ok.... So I might need help from you guys on the forum.

I had everything figured out for a 55 gallon fish tank, but now I'm going to use a 300 gallon tank....

I only have room for 3 grow beds that will be constructed out of 55 gallon barrels cut in half. Plus maybe a few vertical grow tubes, but not right away.

So how do I deal with this huge difference in water capacity?

I just need to match the number of fish to the amount of growing space...right? Plus change more water out every month, right?

Yes it depends on the fish load.

Maybe use three 55 gallon barrels sitting vertically with their tops cut off, rather than half barrels on their sides? Then you could have 150 gallons of gravel instead of 75.

There are other devices like towers and gutters that you could use to grow more plants, could you fit those somewhere too?

Congrats on the tank. I have one just like it and my main growout tank, except I had to pay for mine

As for sizing your system, the thing that's really important is the amount of fish waste matched to your growbeds. You're ok having the extra water, just don't overstock them with fish. Stock the fish as if it were a 75 gallon tank and let the fish be happy not being crowded.

Notmeaning to be overly pedantic but it's actually the amount of feed rather than number of fish that is the limiting factor.

True enough in a sense Chappo.... but it's easier to work out a stocking density in relation to your bio-filtration... than to work out how much feed you'll be using, and work backwards from there to arrive at a number of fish....

How much you can stock... and feed... ultimately depend on your bio-filtration capacity anyway....

General rule of thumb most people use is 3kg of fish per 100ltr of filtration..... happily acheivable with a growbed to tank volume of 1:1....

So just stock to your available volume of filtration accordingly...

Just be aware that if you line the hole and then place the tank in, there is a chance of the tank floating out of the hole with heavy rain!
IMHO only

LOL yea it might..

I plan to only use the lining in small pieces where the cracks and chunks are missing. It will just make it leak less, not leak proof.

[quote=RupertofOZ]happily acheivable with a growbed to tank volume of 1:1[/quote]

So is this about what I should be shooting for?

Yes it depends on the fish load.

[quote=Dave Donley]Maybe use three 55 gallon barrels sitting vertically with their tops cut off, rather than half barrels on their sides? Then you could have 150 gallons of gravel instead of 75.[quote]

That would be a great way to get more bio filtration! and if I do it that way I can fit 4 in nearly the same space to give me around 200 gallons of bio filter, and close to the same amount of grow space.

So about how many gallons of water will need to be recirculated? isnt it 1 exchange per hour? Or 5 gallons per minute in my case?

now, if I can just find one more

SCORE!