Backyard Aquaponics
A place to discuss aquaponics

I think you have adequate filtration for a lot more.

and your punt would be how many arbe?

I would go 250 to 300 depending on just how big they were when you want to start eating them

Sounds good.....but...I really don't need that amount of fish...200 would be max I think and I want them to reach a good size....say 800gm-1kg.
I really don't want to be pushing limits, and don't need the hassle of worrying about the system if I go away for a weekend or week.
but thanks for the input

you could do 300+ if your desperate, but why not KISS, do 100-150, and grow some monsters

then you can host a party and we can all come eat them and drink the home brew

I guess you have to keep in mind that although we talk about growbed volume to fish tank volume, it ultimately boils down to amount of feed in, vs plant numbers. If you have deep beds without as many plants growing as what you might grow if you had the same volume of 20-30cm deep media beds, then fish quantity will also be reduced..

With your IBCs alone you have over 4000L of media, but only 8sqm of growing area. 4 of our beds has only 2000L of media for the same amount of growing area. I don't imagine that the extra media gives you much if any increase in fish stocking levels...

Suits me

Well, you'd still be getting the biofiltration breaking the ammonia --> nitrite --> nitrate, but your capacity for stripping out those nitrates is limited by your surface area. While they have to get to quite high levels to be toxic, if the stripping capacity doesn't match the production, they will still build up. Unless you schedule in regular water changes.

That's another area cookiefisher could research - does nitrate level affect nitrifying bacteria production/processing capacity ?

Very true, but look at OBO's system, 10 IBC's hanging of those massive tanks.....must go read his thread again and look for his stocking levels

Just keep in mind that it's yet to grow out a full crop of fish...

Yep...also he has to stick another 10 on each tank yet as per the design.....I think I may just stick to the 100 for the first run and be happy with that .....now are those crabs ready yet, I'm kinda hungry

We were discussing this last night...

How do bio-filters work in aquariums when there are no plants removing the nitrates?

A couple of months ago I was in at our local aquarium supply place and was taking a gander at their big bio-fiter set-up... works perfectly but they have stuff-all plants in their tanks vs the amount of fish they are stocking... I have been wondering about the nitrate removal since then and just figured the fish must be able to handle it?

weekly water changes . . . same as aquaculture setups. eventually the water gets too 'used'

They do lots of water changes, just like recirculating aquaculture systems.

Ahhh... got it

What a waste of water!

AP ticks all the boxes doesnt it!