What do You use to adjust your pH?

[Katie D]

I'm curious as to what people use to adjust the pH levels in their aquaponics systems?

[Vlad Jovanovic]

Just checking Kate :)

(FYI, you can use HCL from the cleaning section at the store if/when you run out of pH Down. Here it is pure HCL 16-18% solution. The same stuff that the local hydro store sells here for mucho $. Been using it for a good while now, seems to work just as well as any fancy bottled pH down product. They are all just usually either hydrochloric (aka Muratic), sulfuric, or nitric acids. 

After initial tap water adjustments, I've been able to go for almost a month without having to do water changes or adjust pH with anything other than top-ups with a 'home made nutrient solution. pH has been freaky stable? I think this is because I've started adding nitrogen inputs in both NO3 as well as Hummonia to NO4. As opposed to (like I had before) just nitrate only input (50 grams of worm castings, perpetually brewing in a womans nylon sock in the reservoir) . I kind of maybe understand why this is...but it's like a half formed idea in my head. I'm sure that someone else could explain it better at this point in time. The pH just seems 'stuck' at between a comfy 6.1-6.5 zone, there are both nitrites and nitrates in the system, the basil, pepper, and salads are growing super. Again this is a non-fish system.

I wonder if we could ask mom permission to start a 'home-spun-organic-hydro-thread' for these sorts of things?  

[TCLynx]

Vlad, you can start such a thread on your own, you could even start a group for it with multiple threads if you like.  No need to ask Mom.

[Vlad Jovanovic]

Thanx TC. I think i do remember seeing (I think) on your site somewhere,  that that sort of info was welcome here, but  wanted to check first anyways since it's not really AP. Thanks again :)

[TCLynx]

All the more reason to start a tread or group specific to it and you can label it with warnings about it as such.  If Sylvia finds it to be too disturbing to have on the site she has the power to rein you back in but I don't think such a thing is too off topic to have at least a discussion about it on this site.

[Kathy McGrade]

My local water is 8.4 and so I had to find a way to lower it down.  I tried putting driftwood in the sump tank (250 gallon system total) and it did nothing.  I had enough driftwood in there to pretty much cover the surface of the sump tank and left it there for over a month, but the pH didn't lower at all.  Do you know if there's any specifics about the driftwood?  Maybe I grabbed the wrong kind, although who knows why that would be.

I also tried hanging a sock of peat in the highest water flow, and that didn't help either. 

I finally bought an RO system which has lowered the pH in my system, but dealing with the logistics of using the waste water in my soil garden is a hassle.  I'm setting up a system where the RO will fill into one bucket while the waste water will fill a barrel.  Then I can pump the waste water under pressure into my soil garden and the sprinklers will have enough range. 

I'd love to find a better solution though as this is a real hassle. 

My goldfish and koi have adapted to the high pH, now around 8.0, but I don't think the plants like it.  My system is not quite 4 months old now and the pH has never lowered below 7.4 even with significant RO water inputs. 

At one time when the pH was down to 7.4, I wondered if the system had matured and stabilized and tried topping off my sump with house water again, and the pH spiked right back to 8.4.  It seems that might have affected some of the plants as their tops suddenly went yellow.  I'm not certain if the pH rise caused this, or something else.  But the yellowing was very sudden and corresponded with the pH spike. 

[mary proctor]

We used sycamore driftwood from Grand Lake.  We never had to use the moss as the sycamore worked great.  But.......we also have well water, not city "tap" water.  Wished we could have helped
. Mary
Vlad Jovanovic said:

Just checking Kate

(FYI, you can use HCL from the cleaning section at the store if/when you run out of pH Down. Here it is pure HCL 16-18% solution. The same stuff that the local hydro store sells here for mucho $. Been using it for a good while now, seems to work just as well as any fancy bottled pH down product. They are all just usually either hydrochloric (aka Muratic), sulfuric, or nitric acids. 

After initial tap water adjustments, I've been able to go for almost a month without having to do water changes or adjust pH with anything other than top-ups with a 'home made nutrient solution. pH has been freaky stable? I think this is because I've started adding nitrogen inputs in both NO3 as well as Hummonia to NO4. As opposed to (like I had before) just nitrate only input (50 grams of worm castings, perpetually brewing in a womans nylon sock in the reservoir) . I kind of maybe understand why this is...but it's like a half formed idea in my head. I'm sure that someone else could explain it better at this point in time. The pH just seems 'stuck' at between a comfy 6.1-6.5 zone, there are both nitrites and nitrates in the system, the basil, pepper, and salads are growing super. Again this is a non-fish system.

I wonder if we could ask mom permission to start a 'home-spun-organic-hydro-thread' for these sorts of things?  

[TCLynx]

The type of wood and the tannins in the wood will vary the effectiveness of using wood to lower pH.  With really hard water you may have a LOT of calcium carbonate and other alkali stuff to counteract before pH can drop significantly.  If you have to use tap water to top up instead of the RO water you may need to use some muratic acid or something to get a jump on some of the excess carbonates your water seems to have.

If you must use acid to adjust water.  I recommend doing it in a separate barrel and letting it stabilize before using that water to top up the fish system.

[Kathy McGrade]

Thanks.  I've got that going right now, a separate barrel of highly alkaline tap water to which I added muriatic acid and left it for 24 hours with a bubbler.  This morning I added a couple buckets of this conditioned water into my smaller AP system and the goldfish there are still alive.  I'll keep playing with this and report back when I have more data logged. 

[Ben Stallings]

Sorry to reopen an old conversation... hope that's OK.  On the advice of the API test kit instructions, I bought a bottle of Proper pH buffer crystals, but after I left the store I read on the bottle that it's not to be used in systems involving live plants.  I'll return it to the store, but I'm curious, what would the effect be on plants?  According to the MSDS sheet for the product, it's 1-5% sodium thiosulfate and 1-5% EDTA tetrasodium salt.  Thanks for any light you can shed.

[TCLynx]

If you were to regularly use the sodium based buffers the salt levels in the system will likely rise to a point at which your plants would suffer badly.  Remember that in a normal aquarium, YOU DO WATER CHANGES.

In aquaponics we normally DO NOT DO WATER CHANGES.  In aquaponics we normally only top up unless something goes terribly wrong.  So whatever you add to your system, you want to make sure it is primarily things that the plants will use up in about the same ratios that you will be adding them.

This is kinda why I don't recommend using acids to adjust pH all the time since almost any acid will be adding something to the water.  For instance, if you are constantly adding hydrochloric acid to your water to counteract the calcium carbonate, the result will be that the water you are using in your system will have a large amount of calcium chloride (which as far as the plants are concerned, is also a type of salt so you don't want to use too much of it too often unless you are growing all salt tolerant plants.  I have tested this out some and the strawberries didn't thank me.)

[G Mo]

My ph is 6.4 and i was going to add some pellitzed lime.  Anyone have experience with this?  Suggestions on how much?  Looking it up there is a lot of general info and I was hoping to get advise from the sages.

[Jeff S]

A good way to raise your PH is with Hydrated Lime and Potassium Hydroxide. Very small quantities of each. I just raised PH from 4.1 to 6.8 with about a half teaspoon of each in a 45 gallon aquarium. Fortunately I don't have fish in that system since it was a rapid adjustment. So you can see how little it takes. The reason for using these 2 elements is that they provide excellent nourishment for your plants while buffering the system. Be careful not to get them on you with water because they become a strong acid.