Backyard Aquaponics
A place to discuss aquaponics

Starting Sunday, added 1 oz Hydrochloric acid to 5 gallon well water. Sump was low and needed to add about 20 gallons. Added a total of 4 oz to sump. starting PH 7.6. Ending PH about 7.4. Checked again Tuesday, PH back to 7.6. Plant growth and fish seem fine, although I don't have a comparison in regards to plant growth in an AP system, since this is my first. It's not as good as Ryan's (Chatterson's farm), but then again, I haven't seen anyone's that compares to his quality. I'm shooting for that as an ultimate goal, but fear I have a looong way to go.lol Right now, what the hell do i do about this PH? Why does it keep leveling off at 7.6, and even when adding acid, still not get any lower? I've heard the horrors of "chasing PH", but also know that 7.6 is too high for optimal plant growth. All other levels are fine, and fish are eating and growing. Got some new kale today, so will be planting lots of kale in GB's and maybe a kale tower?? Anybody try that? thanks for any suggestions.

I wish I had 7.6. Why are you trying to lower that. My system has been over 8 for over 2 years now. My top up water is low 7, but I can't get it lower. My plants are growing great, fish are eating, so for now I am happy.

When treating the top-up water with Hydrochloric acid it has to be brought down into the low 6's and kept there for a few hours, preferably a whole day. This will consume any carbonates in the top-up water so you're not constantly topping your main system up with carbonates. If you do this with every top-up your system pH will begin dropping sooner than it otherwise would have, but it takes time.

I had a system that sat around 7.8-8.0 for over a year, it required lots of topping up, about 20-30% per week, due to it being a small system with high evaporation. Our tap water here is high in carbonates and I was simply topping the system up with carbonates on a constant basis. Rupe mentioned about treating the top-up water with acid, so I started doing it, it took nearly two months for the pH to start dropping on it's own, but it did. I now control the system pH by treating, or not treating, the top-up water with acid (and the occasional pinch of Pot' bicarb).

At 7.6 your plant growth should be fine. The occasional pinch of Chelated Iron will help.

Damage & "helomech" : thanks guys. Damage, I took your advice before....just didn't wait long enough and as always expect things to happen too fast. I'm learning...will stay the course and let the adjusted water sit for a the better part of day before adding.I have a lot of kale to plant today...tomatoes are starting to bloom, strawberries shouldn't be far behind, herbs looking good. Peppers are slow, but starting to grow. kale is supposed to be very good for you, so it looks like a lot of kale in our future. i'm not a huge fan of the taste...any good recipes?

At 7.6 I would't worry about it as long as the fish and plants are doing fine. Soon you will be having to add things to raise PH and will wish for the days you had 7.6. As long as it isn't getting higher I would leave it alone.

hey, enjoy that pH. Cause very soon you'll start the constant battle of trying to raise you pH!

I keep hearing this, but it is not true for all of us. 2 years and still over 8, tested everything, and have no idea why.

Helo, what is the substrate you have in your grow beds? Wondering if that could be the reason.

It is river rock and I tested it over and over. Did the vinegar test no bubbles at all. Also took two samples one I put AP water in with a ph of 8.4, the other I put pond water with a ph around 7.0. Tested both samples for over a week. No real change in either one. Kept both samples inside and covered.

Hi All,
Also having a high ph issue here, I also used river rock initially and my ph is also hanging in the mid 8s about 4 months ago we swappednout aboout half my grow media with broken red brick and seem to have a slight improvement, eg about a 0.1drop in ph per month or so rather than the solid 8.5 ph I had when I was just running pure river stone. Also ran all the tests on my river rock and it seemed to pass them all. Im guessing that long term testing of the river rock might unearth some more interesting results, but who has the time to do that lol.
The tap water being high in carbonates makes the most sense though as on one of my tests I noticed a great improvement in ph and water stability after using water that I had been treating and finessing for over a week to achieve a perfect stable 7.2 ph.
But the truth is the problem could be a group of things that need addressing ratherthan one single issue.

I checked everything. I have used two different fish tanks, all my grow beds are IBC's that are food safe. I have no metal in my system at all. My top up water is from my pond which has a ph of 7. My tank is covered (mostly) from the sun. The only other things in my system are pvc pipe and pex pipe.

I basically have the same problem, my system has been running for about 8 months now and my ph is still very high. Granted it has dropped from a solid 8.5 to 8.2. But honestly I doubt it has been anything I have done that dropped my ph, more likely it has finally just started to drift down naturally. I have started adding small amounts of EM (effective micro-organisms) which has a natural ph around 3.0 and serves a dual purpose in that it helps bolster the bacteria population making your growbed a better filter.

How often is your tank water being turned through the growbeds?

Who are you asking this of?

If me, that is hard to say. Each bed is different. One is very slow and takes probably 15 minutes to fill up, one is very fast, probably fills ever 4-5 minutes, and the rest are in between.

The total volume of your fish tank should be cycled through the growbeds once an hour. If this isn't happening the water isn't being filtered enough, and could explain your constant high PH.

Just a thought on what may be causing you guys difficulty with PH.