Backyard Aquaponics
A place to discuss aquaponics

I'm not a fan of continuous flow growbeds Al... IMO they just cause too many problems whereas flood & drain works well, consistently.... and I think you would have found problems with nozzles and sprays blocking eventually anyway...

Flood and drain all the way!

I have the small system running on cont flow, and it's nothing but trouble once you start to add quite a few fish. The waste processing is not as good.

The large system has 24 siphons, and they all work perfectly - no blocking or water quality problems, even with a pretty good fish load.

Flood and drain timers = 15 min on, 45 off or similar.

If you can flood the new beds for 5 minutest each hour, 24/7 for the first few weeks, you will probably get better bacteria colony going in those beds quicker. Then once those beds are going well, perhaps you can convert your old beds to flood and drain too. Problem with continually flooded gravel is you don't get as much bio-filter from it and the same size flood and drain bed. Probably do to lack of sufficient aeration for the continually flooded volume. This can also easily explain dead or dying seedlings, deep water culture (which is what a continually flooded bed really is just with gravel added) usually needs lost of bubblers down under the plants to keep them doing well.

You will probably find that once your flood and drain beds are online for a while, the ammonia and nitrite readings will drop to 0 once those beds are cycled. Don't worry too much about Nitrate until it goes off the chart.

Thank you all very much.
I was thinking that I should eventually make them all flood and drain.

How many fish do you think a 1600 l tank with 2 bathtub and 2 1/2 blue drum grow beds could support once it is cycled and loaded with plants?

Each bathtub would be 200 litres of gravel, each 1/2 barrel is 100l = 600 litres.

600 litres can support 40 - 60 large fish. Once well established. First season I would recommend 40 fish at the most.

I disagree ... 600L will support 20 large fish.... @ 3kg/100L....

If you were going to try and exceed that density... you'd have to have a "mature" system and preferably 1600L of growbeds to acheive a 1:1 ratio... if not more to approach 2:1....

AAAH - woops

I was thinking of water tank volume. As rupe says

Ok thanks for that.
Based on 3kg for 100l grow bed volume I will be right for some time yet.

Cleaned the Dacron from the Bio filter yesterday...
Very mucky - looks great for the garden.
Does anyone use solids filters attached to their water outlets?
I am wondering how effective they would be after seeing the muck in the bio filter.
It was very fine.
But I can see that they would make life easier if some one has an effective idea!

No, we prefer the solids to enter the GBs and let them do the filtering!

Thanks Creative 1.
You are in one of my favorite parts of WA.

Do grow beds need cleaning out after a while?
Do the solids create congestoin limiting water flow eventually?
Will it get smelly with a build up?
Will worms eliminate any or all of the above?

Will worms eliminate any or all of the above?

You got it!
Yes nice part of the world, but still got the same s--t to do as anyone else.

My system is only 6 months old, so in truth another 6 months will tell me...
but I don't see it being a problem.

Flood & drain provides a highly oxygenated environment Al... your growbeds should never get "smelly"....

Such a condition would infer anerobic zones... and your fish would probably let you know before your nose did...

+1

+1 for worms

Thanks you 3...
Will get some worms over christmass days off.
All the best for Christmass!