Natural ways to bring down PH

[Adam Garrett-Clark]

Hey Everyone,

Does Lemon juice work to reduce PH in a system?

I bought some rock wool to start some lettuce seeds and the back of the package said to use lemon juice to reduce the water ph to 5.5 to start the seeds. 

I figured this would work in my system as well, which has been consistently coming up with a PH of 8.2, so I squeezed a few lemons into the system and tested the PH the next day and I noticed that the PH went down to 8. So I squeezed a bunch more lemons in. I put about 12 lemons worth of juice into my barelponic system, about 55 gallons of water.

I think the answer to my question is no, because my I tested the levels today, and my PH is still at 8, and all my other levels are weak. I'm about 2 months into cycling my system. My amonia already spiked and was consistently reeding 0.25 ppm, now its at 0. My Nitrites were reading 5ppm now they are 2 ppm and my Nitrates which were at 40ppm are now at 0. Did I just kill all my bacteria? Is all this lemon juice bad for the fish? 

I only have 2 gold fish that have survived the cycling. Should I add more fish? Should I change the water and start again? I have a lot of new growth in my grow beds right now.  is the lemon juice bad for the plants?

[Bryan Acred]

What mineral supplements did you use Adam?

[Adam Garrett-Clark]

I used a product called Equilibrium,

it says its main ingredients are:

-Soluble potash

-Calcium

-Magnesium

-Water soluble magnesium iron

-Water Soluble Iron Manganese

-Manganese

Also my fish have a bunch of bubbles on their skin around the tail especially, at closer look it looks like theres some sort of scum on the skin, this is probably a bad sign right? anyone ever seen this?

[TCLynx]

Do a vinegar fizz test on some of the media to know if it is causing your high pH.

[Adam Garrett-Clark]

So I did a vinegar test and didnt see any fiz. THen I let some filtered tap water, which I use to top off the system, sit in cups of media for a day and got some interesting tests results:

the filtered tap water tested at 8.2 PH which is the same PH as my system. 

I used four cups of media soaked in the filtered water. 2 cups for each type of media. I have a mix of black volcanic rock and pea pebbles as my media. 

All 4 four tests were identical. And I tested everything twice to make sure. the HIgh PH test came back with a 7.4 PH for all four samples. The regular PH test came back with 7.6 PH. 

eitherway this is way better than the PH in my system. Does anyone know why that would be? or how I can use this information to lower my PH. I'm thinking maybe I should stuff the drainpipes coming from the grow beds so that the water stays in the media longer and would maybe lower the PH that way. 

[Vlad Jovanovic]

I might have missed something...but some of the items in that ingredient list for your supplement you listed (Equilibrium) would seem like they might raise pH... ?

[Vlad Jovanovic]

Particularly the main ingredient (assuming you listed them in order).

Potash A.K.A Potassium Hydroxide (KOH) is a pretty darn strong base.

Might at least in part have something to do with it...?

[Adam Garrett-Clark]

THanks Vlad, yes I think I did list in order, Soluble Potash is at the top at  23%. I've been having high PH from the beginning, and I only started adding the water treatment recently. But you're right if its a strong base that might be part of the problem. So I've consulted my Aquaponic Food Production book by Rebecca Nelson and she says to use either Nitric, Phosphoric or Acetic acid to bring down PH. I did some quick wikipediaing on these acids and it says that Acetic acid is the main component of Vinegar. Can I just add some vinegar into my system rather than figuring out how to aquire these strong chemicals? I'll wait to hear people's responses before I do. the Lemon idea I had didnt turn out very well. Any problem with vinegar? My last PH reading was 8.4 and my plants look like they're not growing at all.

[Jon Parr]

Vinegar is also anti-bacterial, I'm told. I'm surprised Nelson mentioned acetic acid, and I'm unaware of any commonly used acetic acid other than vinegar. I'm also surprised she didn't mention muriatic (hydrochloric acid).  

[Adam Garrett-Clark]

So if I put vinegar in my tank, I'll kill my bacteria huh?

[Eric Warwick]

Yeah, but depending on your fishload and biofiltration capacity, the occasional acetic acid should be fine.
 
Adam Garrett-Clark said:

So if I put vinegar in my tank, I'll kill my bacteria huh?

[Jon Parr]

I've not done it, but I've read that vinegar is a no-no for AP.  I'm sure Eric is right, a mature biofilter can probably handle it, but if your water is 8.4 and you are probably wanting it somewhere in the mid 6's, then you are going to be using quite a bit. And remember, adjust pH slowly, I think .2 per day is recommended.  Also, take a reading at the same time each day, as dissolved CO2 will change the reading from morning to evening.

[Eric Warwick]

Here's an idea, add a CO2 bubbler and get Carbonic Acid, which should lower pH. However. this is the main indicator for someone growing weed (I have some pretty funny stories from my *local hydroponic store--which is 1/2 block from a cannabis dispensary).
 Jon Parr said:

I've not done it, but I've read that vinegar is a no-no for AP.  I'm sure Eric is right, a mature biofilter can probably handle it, but if your water is 8.4 and you are probably wanting it somewhere in the mid 6's, then you are going to be using quite a bit. And remember, adjust pH slowly, I think .2 per day is recommended.  Also, take a reading at the same time each day, as dissolved CO2 will change the reading from morning to evening.