Backyard Aquaponics
A place to discuss aquaponics

Relatively new system, pH about 7.6, using mostly rainwater, some relatively clean river water, rain = 7.8, used homemade banana vinegar, pulled down to 6.8 target, added too fast killed some fish [tilapa], over a week, back up to 7.6, don't want to keep adding vinegar, it also discolors water, in Belize, difficult to find most common AP supplies, ideas?

Short answer, do nothing... Let nature take its course...

What are your other water test results?? Ammonia, nitrite, nitrate?? Water temperature??

If it is a new system and still going through the cycling process, don't worry about a pH of 7.8 ... As part of the
nitrification process, the pH will start to drop naturally. No acid/vinegar required... Just nature, time and patience...

How new?

I've been wondering the same thing.
My pH is at 8.0 and has not changed in the past 4-5 weeks since cycling began.
Ammonia is now at 0.3, Nitrites 1.0, Nitrates 10...
I was hoping that as the system stabilises that the pH will drop but I'm beginning to wonder as I can't stock it yet until the pH comes down.
The media is 1/2 scoria (volcanised rock) and the other half is clay pebbles.
Cheers
T

My first barrel system, the pH dropped suddenly just about the time the Nitrites dropped to 0.

In my later systems that are full of shells, the pH took about a year to start getting below 7.6 because the shells tend to keep it well buffered.

+1 on the advise to do nothing. IF the pH is being buffered up, adding acid will only cause bouncing until the buffer is completely dissolved. If the pH is just up because the system is new, then leave it alone so nature can take it's course. Only issue is that with the high pH adding chelated iron may be necessary to make the plants happy.

+1

Just wait until it is cycled completely and add fish: they will almost certainly be fine. I had trout at ph of 8.8+ starting a few months ago (now 8.4 and dropping naturally) and they are fine.

I added shell grit under the layer of clay pebbles to each growbed, so I guessed that might be what it was.. The plants seem to be doing fine as I'm adding Seasol and Charlie Carp (fish emulsion) to the system each day to keep the ammonia and nutrient levels going.
I'm interested with Hydro's comments on the trout too which is reassuring as that is what I'm stocking with. Rainbows..
Thanks for the input.

I wouldnt worry too much I used bore water which was 7.2 out of tap and 8.6 when bubbled over night....I put in 700 Jades lost one(1) the next morning most likely from the travel....these fish were between 7-12cm long two weeks later the ph is sitting 7.4-7.8 in the four different areas and the fish are between 9cm-18cm long..

What media are you using??? if it is stone put some in a cup add vinegar and if it bubbles lots then the stone is limestone based therefore the ph will be higher..

Ya know, most fish don't mind a high pH so long as there isn't any measurable ammonia. Tilapia are fine in high pH water and my catfish haven't complained about it either. It is only the plants that have issue with the high pH and that is just because they have trouble taking up certain nutrients when the pH is that high.