Backyard Aquaponics
A place to discuss aquaponics

Hi all!!

Aquaponics newbie here, situated in West End in sunny Brisbane

Been gardening for a few years and made the plunge into aquaponics in Feb this year and loving it! My plan one day is to upscale and become fully self-sufficient, but for now just starting out with a pilot system to learn the trade... plus i'm renting lol

Began with an 800L IBC fishtank and 500L growbed (2sqm x 25cm deep) with bell siphon and 20mm tumbled bricks for media. Unfortunately fell prey to the "1 fish/10L" rubbish espoused elsewhere and so started with 50 jade perch thinking I would be fine. Everything was sweet for the first couple months (after cycling), but for the last couple months have been observing consistently high levels of ammonia (~0.5ppm) even after slowing feeding to once every day or even less and doing large water changes...

I read the excellent comments on this forum about stocking density (cheers Rupert! ) and realised I was overstocked, so installed two more grow beds (@ 230L each) hoping that would fix my ammonia problems, but although it is a month on now and they should have cycled I'm still seeing 0.5ppm ammonia, even with only <10g food/day. Ph = 7.4, nitrites are nil and nitrates are ~120.

Just wondering if anyone has any thoughts on what might be happening?


Some thoughts / possibilities:

- I've been filling the original growbed at a single location, and so thought perhaps a dead zone might have built up, but was skeptical it could become problematic in just a few months... I hate to disturb the plants but my next thought was to perhaps stir the media to try dislodge solids and turn the system aerobic again..

- Also the original growbed is (unfortunately) located in too shady a location, so have only had success with herbs and salads that don't mind shade. So I also wondered whether reduced uptake of nitrates might be allowing some kind of de-nitrification to occur? Counting against this is the nil nitrite reading, which I would have expected to see...

- another thought was that the winter weather (or my over-exuberant water changes) might have killed off the bacteria? I have an aquarium heater set to 22oC but given the system is outside I'm not sure it's doing much to keep the water warm..

- even thought that my ammonia test kit might have become contaminated from swapping lids, but fairly sure this is just wishful thinking


Aside from that, would very much appreciate any other thoughts anyone might have!! This one has me stumped!


Thanks!!
Coops

Welcome to the forum Coops

Sometimes cycling a system takes awhile . Looks like your weather is nice there but what's your water temp been for the last month? The bacteria slow down when it cools off. It looks like your partially cycled but you probably aren't running into ammonia toxicity with that pH unless your water temp is a lot higher than I think it is. Keep at it you're just about cycled

You should consider thinning out your fish, invite a couple over for lunch

Welcome.

Jades have a low tolerance to cooler weather/water, especially when they are small. There are other members in your area that have had to be careful growing Jades out through winter. You really want to purchase them at the end of winter and get some weight on them before the cooler months arrive to give you a better chance. Unfortunately the aquarium heater won't help.

As Scotty mentioned cycling can take time in winter, maybe up to 6 - 8 weeks. Combine this with your fish load and fish stress from cold water this is why you are seeing a consistent amm reading.

Id recommend stop feeding all together for a month (the fish will be fine) and do small water changes during the day, once you get your amm down stop pumping during the night to assist keeping the FT temp up a bit. Salt the system to 1 or 2ppt with pool salt.

Another note is your on the heavy side of stocking in regards to FT capacity. 50 Jades in 800L will push the oxygen levels in summer as Jades are ferocious feeders in warmer water. Make sure your well aerated and turning over the FT volume at least once per hour.

There a quite a few members in your area if you decide to off load some fish.

Hey all and thanks for the advice I've considered thinning out to around 30 fish but would prefer exploring all other options first winter was very late to arrive this year so I had a good three months to cycle the first bed in 20+ degrees, but good to know my other beds probably aren't ready yet. I'll keep waiting!!

Have noticed that amm drops ever so slightly after not feeding for a week so will return to that strategy... Was just trying to keep my jades growing and I have multiple air pumps so oxygen should be ok, but great advice on turning the pumps off at night, fluctuating temps have probably been wreaking havoc on the bacteria!

Here are some pics for posterity. Parsley and chives are loving the first growbed, and I've also had success with mint and evergreen salads:

[IMG]http://uploads.tapatalk-cdn.com/20160727/ccec7a9a0eae2402ba35d7f100c0904f.jpg

And decided to use IBCs for the new beds... Much easier than building a timber frame!!

[/IMG]



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Oops pic of the original growbed didn't seem to load...


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Hey coops, I liked your technique to build the bed.

Haha thanks! I like to recycle so built it out of mostly scraps I found at kerbside collection... including a trundle bed base that is now bowing in the centre due to insufficient reinforcement! Turns out 500L of gravel is pretty heavy lol. Hence the much easier second version 2 made from IBCs