Backyard Aquaponics
A place to discuss aquaponics

So I'm currently using a cartridge type filter before my DWC bed. I have to clean the element at least twice daily, and am rinsing the fish waste(and other solids) into potted plants. Would I be better off rinsing it into a bucket and aerate it to then add back into system? How long would I need to let it "sit", and are there any additional things I would need to do? Would I add the water to GB or sump? Does it matter?
Thanks! Gold tilapia are growing like crazy and already showing mating behavior...should be some babies coming shortly. Need warmer weather to get them in their new "digs"...a 500 gallon spa that is going to be my new FT.

We might have already had this discussion so if that is so please forgive me.

There are valid reasons for removing the solids from your system and if it is something that is appropriate to your situation then you would be silly not to but the maintenance issue you are facing is one of the biggest reasons for not removing the solids. BYAP systems which have GBs as their only filtration work perfectly well as long as the size of the GBs is sufficient to cope with the rate at which you feed your fish.

Having said that....

From my understanding a mineralisation tank is merely a tank that is given enough aeration so that the bacteria have all they need and that there is sufficient turbulence and mixing so that the solids remain suspended in the tank.

To this you may add a bottom valve to remove sludge and a top valve to remove water to add to your system.

To work out the specifics of the design you would first need to know:

- how much solids the system has to handle.
- rate of O2 you can add to the water with your aeration method of choice
- rate of mineralisation based on temp and available O2.

Once you had those numbers you would be able to work out the:
-size of the tank
-method of mixing
-rate of mixing

The alternative is just get a tank and add as much air as you think appropriate and locate the air stones near the center so that you get a mixing current going up in the center of the tank and down the sides.

On the forum the only person I know who would actually have experience designing a MT rather than just guessing is Ryan.

Why clean the cartridge so frequently. If you have enough DO in your system the mineralization will occur in the cartridge filter. The only thing you need is an out gassing tank between the cartridge filter and your DWC beds.

Stuart, thanks...I think this gets in headed in the right direction. Probably right about Ryan and the MT. Jeff- Since I don't have my GB draining into my DWC bed, I was forced to put the viewflow filter inline between the sump and DWC bed. The problem of too much debris/solids fouling roots in DWC bed was solved, but the maintenance is an issue. If I don't clean it twice daily, then the flow going into the DWC bed is inadequate(much like I feel doing this AP at times). Also thinking that washing away the fish poo was counterproductive to having the best growing conditions. Hence, the mineralzation tank. I will try a bucket and airstone and a couple of ball valves and see what happens.

Yep just chuck a big air stone in a bucket and put the poopy water in. Leave for a few days then take out the air stone and let the solids settle. Pour off clear water back into your system if that is your want, or just put the whole lot on the dirt beds or compost bins

Joel incorporated a digester in the BYAP commercial trial. Conical bottom tank which would collect solids externally from the system, digested and then returned periodically. Much is to be learnt from this process and the people doing it havnt documented too much about it or shared too much information. Ill be doing some testing myself in my new system and working it out on my own and happy to share experiences later in the year.

Mantis, thanks...exactly my plans (:
Charlie, keep us posted...will be interesting to see results.

48-72hrs? Is there a consensus on aeration time, fish solids/liters of water in a MT?
putting in some crawdads wouldn't hurt either?

Testing this myself as we speak, according to W.Lennard aeration time in MT is 4 weeks!

I have a MT that I feed with the drain from the RFF... I try to drain the RFF every 3-7 days depending... and when I do that I also pump out the MT back into the GBs (after taking out the air stone and letting any solids settle to the bottom of the MT). I have taken an ammonia test on the water from the MT after 7 days and it has been 0-0.25... what else would be needed than a low ammonia reading to be sure the water is 'aged/treated' enough? Perhaps I do not have that much solids coming from the RFF but I also don't have a lot of air in the MT.

With a swirl filter and mineralisation for 48hrs I saw a reduction in growth,I have now removed the swirl but added a smaller version before the DWCs,the solids from here I dump,in the main system with solids going to the beds growth has picked up.
Before the DWCs I have a 60 litre swirl feeding then into a 200 litre barrel filled with shade cloth,there is still a little detritus in the bottom of the DWCs but none on the roots.

You add the fish solids back into your media bed correct?

No you mineralise them by putting them in a container and heavily aerate it,48 hours or more you let it settle decant the clean water and add that to your system.
I believe my error was in the remineralisation process,I need to look at the way I was doing it and maybe rethink

Wilson Lennard stated 4 weeks to fully mineralise, he also stated that the MT should be allowed to settle and the clarified component drawn off daily, with new solids added daily (for commercial systems).