Lowering PH with Vinegar?

melypr1985 · Jul 1, 2015

I'm upgrading my 40 to a 75 tomorrow morning. I have a lot of live rock sitting in a 75gallon Rubbermaid tub with a power head. I've been "collecting" saltwater in this tub to help fill up my new tank. I went and had the water in it tested, because I have my doubts about the soundness of this idea. (my husband used two different salts to mix the water originally put in this tub when the rock came in... I was out of town

) I also wanted to make sure the parameters were as close as possible to my current tank. The results were pretty fascinating. My PH tested over 8.8. The tests they use don't go higher than that. So, I've heard that you can use vinegar to lower the ph in salt water. What I'm hoping for is warnings, things to watch out for and maybe a calculator on how much to use. Thanks in Advance!

The rest of the test results:
Rock Holding Tub:
SG: 1.024
PH: 8.8
Alk: 143.2 (meq)
Ca: 320
Nitrate: 5ppm
Nitrite: 0ppm
Ammonia: .75ppm

Current display:
SG: 1.025
PH: 8.0
Alk: 143.2 (meq)
Ca: 420 ppm
Nitrate: 10 ppm (weird since I never have nitrates, but understandable since I tend to overfeed)
nitrite: 0 ppm
Ammonia: 0 ppm

melypr1985 · Jul 1, 2015

I always do this. I ask a question then do more research and find an answer that way. Then my question is just hanging there and I look stupid. Well, I don't care...I'm leaving it here because I would still like to hear other experiences using this method and warnings and things to look out for.

I read Randy's article on this subject and while most of the language made my eyes cross and went completely over my head, I did get the formula for the vinegar to water ratio. Thanks for that! I'm not going to try this until this evening, so I hope I get some insight into what to look out for while doing it before then would be awesome.

hart24601 · Jul 1, 2015

What test are you using for pH? If it's just an inexpensive test I would doubt the results are all that accurate before I started adding anything to the water to decrease pH. I am sure Randy will chime in with better advise soon!

melypr1985 · Jul 1, 2015

I believe the LFS uses API test kits. I made him do it twice, both with the same results... not sure if that makes much difference though.

Randy Holmes-Farley · Jul 1, 2015

Assuming you are not adding anything except salt mix, and are aerating it, the test is likely inaccurate. High pH doesn't just happen and should not be a concern for you.

Daytonareefing · Jul 1, 2015

I agree you may want to invest in a salifert PH test. That just sounds way to high. Tell your husband he made the mistake so you need him to buy you a new present ie a salifert test. Lol

Randy Holmes-Farley · Jul 1, 2015

melypr1985 said:
The rest of the test results:
Rock Holding Tub:
SG: 1.024
PH: 8.8
Alk: 143.2 (meq)
Ca: 320
Nitrate: 5ppm
Nitrite: 0ppm
Ammonia: .75ppm

FWIW, those alk values are in ppm (calcium carbonate equivalents). Alkalinity is generally about 2.5-4 meq/L, whhich equals 7-11 dKH or 125-200 ppm.

melypr1985 · Jul 1, 2015

Well dang... looking dumb again. I just went off what the guy wrote down for me. Ill get a test kit of my own.... although i hate doing it.

melypr1985 · Jul 1, 2015

Ok. How are the red sea kits at ph? I already have other red sea kits and i like them a lot.
Is it really impossible for the ph to be that high? Its had 120lbs of live rock in it with a power head for about 2 weeks. There was two different salts used to make the water in it. Instant ocean and Frits, not sure but could that be one reason? Assuming the test was accurate that is.

Daytonareefing · Jul 1, 2015

Red sea is ok but there ph may read ok then the nitrate test may not read right I'm not saying that will happen but after you been in the hobby long enough most people go to salifert because it seems to be the most accurate. I have had so many tests of the years that just don't read right that's one reason I went to an Apex controller with a lab grade ph probe but I know sometimes its hard to afford. I started out with a cheaper master test kit and it did work ok but that was over 15 years ago.

melypr1985 · Jul 1, 2015

An apex is on my list for Christmas.... my husband is just thrilled about it lol. So until then I think I'll just get the red sea kit. Its the only other one they have in stock besides the API kits. Plus he's only going to charge me $10 so really I think I win. I'll run the test tonight and post my results, then go from there.

melypr1985 · Jul 1, 2015

I tested with the red sea kit and it is definitely 8.6 or 8.8... this test only goes to 8.6 but it looks darker than that. So I administered half of the recommended dose of vinegar and will test again in a bit. I'll put the rest of it in (according to what it tested) before bed and test again in the morning. Thanks for the help!

Daytonareefing · Jul 1, 2015

I would still be concerned what caused it to get that high. Are you using R.O. water to mix the salt with?

melypr1985 · Jul 1, 2015

absolutely! ro/di and I do periodically test it with a TDS meter to be sure they are giving me proper water at the LFS. I haven't a clue... I mean, I had 1 power head in there but it wasn't breaking the surface of the water. So after reading Randy's article I put a second power head in there and put both where they break the surface some.... just for better gas exchange.

What if, I opened a brand new bucket of salt? I didn't stir this salt up or anything just scooped off the top. I heard a rumor that maybe, in transit the finer particles in the mix float to the top. Those finer particles (supposedly) are the buffers and that maybe that's why the PH got so high? What do yall think? Fact or fiction?

Downbeach · Jul 2, 2015

Do you have a venturi device you can add to the PH you're using to provide a better gas exchange? Do you know anyone who has a properly calibrated pH meter? Over many years in this hobby, I'm only aware of two occasions where someone's pH got high, and both times it was due to an ATO problem with the float switch sticking on and adding too much top off with fully saturated kalkwasser. Even then it only got up to ~ 8.5.

melypr1985 · Jul 2, 2015

unfortunately I don't know anyone that can spare their ph meter. I find this all very odd myself, and I was really surprised to see the results of the tests. I tested it myself and got the same thing. My friend and I could only come up with a guess that involved the salt mix I just opened and used. Although that sounds fantastic and unlikely, it's probably just our minds racing to make the problem make sense to us. Is it possible that the live rock I got has a problem? Its Reel Reef Rock that I won in a raffle. Despite the name it's eco rock and comes fully cured and live.

I have gone ahead with the vinegar dosing. I've been putting in a 50ml at a time, going off the assumption that I have about 50 gallons in that tub. (I'm not sure because we have added to it over the two weeks and with the displacement by the rocks I just don't know) I put 50 ml in last night looking for a drop of .3 in the PH. That's was successful so I must have about 50 gallons of water in there (lucky guess). I put another 50 ml in there last night and tested again this morning and I was down to 8.2 ish. So I put in 25 ml of vinegar and will test again in an hour or so. My goal is to match the ph in this tub to the ph of my current display.

Randy Holmes-Farley · Jul 2, 2015

pH is a low priority measurment for most reefers (many do not measure it at all), and meters are much better than test kits since you can calibrate and check the performance of a meter.

Randy Holmes-Farley · Jul 2, 2015

melypr1985 said:
What if, I opened a brand new bucket of salt? I didn't stir this salt up or anything just scooped off the top. I heard a rumor that maybe, in transit the finer particles in the mix float to the top. Those finer particles (supposedly) are the buffers and that maybe that's why the PH got so high? What do yall think? Fact or fiction?

Before adequate aeration, some salt mixes may read pretty high in pH, but aeration will bring it down. In the past at least, some started above 9.0.

By far more people have low pH problems than high, unless they dose limewtaer ((kalkwasser). Almost never is pH otherwise too high.

melypr1985 · Jul 3, 2015

Thanks for the help guys! I really appreciate it. I was able to lower the ph of the water in the rock tub to match my display and I was able to use the water in my upgrade. So all is well. I just wish I knew why the ph was so high to begin with! It's weird! Well, hopefully I wont have that problem again.