Backyard Aquaponics
A place to discuss aquaponics

Aloha and thanks for your interest.

My question is regarding the cleaning of growbeds. I am in the process of constructing my 1st AP system (see link in signature). I have a coworker who has been into hydroponics for some time and he is considering the move to AP. This hydroponics friend of mine has repeatedly insisted that I will eventually have to pull everything out of my growbeds and clean the sludge (fish waste) out otherwise my system will become choked. I have done quite a bit of reading and video watching on the subject of AP and haven't see any mention of this growbed cleaning as a necessary evil. On the contrary, I have seen mention of growbeds 2-3 years old and older still flooding and draining and producing lush plants. It seems to me the beds just get better with age!

I think my hydroponic friend is influenced by his practice of hydroponics and the constant need to remove solids from the effluent. Who's right here?

You're both right.

It depends on your stocking levels.

Have a look at Faye's system. Going for 10+ years without a cleaning, and no problems at all.

If you have more fish than your filtration can handle, you'll need to clean out your GB, if you get the right amount of fish, you might not need to.

We lack enough systems on here that have been going long term to give you a proper answer. I've seen it said a few times that it'll need to be done every five years or so, but it depends on plenty of variables.

^ This.

if you are worried about cleaning there is always the option of radial flow or swirl filters before the beds to reduce the amount (and size effectively) of solids going to the growbeds.

Okay, cool. Thanks for the replies. I was planning on installing a radial flow filter after my fish gain some size. I didn't think it would be necessary at the beginning stages. Actually, I thought the beds would actually benefit from having all the "nutrient" they could get in a new system. Plus, I think my growbeds are on the large-ish size for an IBC system so I assumed that with that much media I would be safe especially after the install of a RFF maybe about 6 months in.

+1 - What they said

Stock lightly - doesn't take many fish to feed the plants. Stocking too many leads to needing to clean the grow beds.

Have worms in the grow beds to help clean them out and break down solids.

Having an RFF is always an option to slow the accumulation of solids if you want to overstock.

Running for 3 years now without a cleaning on my current system (No RFF)

Cheers

It sounds like you basically kknow what you are doing Squatch.
the bigger your beds vs. amount of fish, etc the more the waste will be spread as you were alluding to, so you are on the right track.

Ahh tell him he's dreaming.

Just stock sensibly to the media capacity of your grow beds and they will easily use up all that poop without filtration.

You can always expand the system media capacity later or increase fish production and add filters Etc. when you really understand what makes your system tick.

Thanks for all the replies guys. I'll explain all the facets involved to him next time I see him. Thanks again.

Be gentle with him. His experience of filters is most likely of quite small ones that even with clear water need to be cleaned frequently. Or even all the time depending on the media he uses for seedlings.

With GBs just like with many other production systems rate in must equal rate out or the system will fail. Since the time it takes for solids to be fully processed is quite a long time the rate in must be relatively small/slow to allow enough time/room for the solids to be processed.

Very cool! I'll probably see him tonight. It will be interesting to here his opinion.