need help with ph! way high

[clamm]

nuno, i also found as you did that sal from the instuctions were low. but i would correct it with more salt and still add superbuffer. in order to take care of dKH.

 

[denvig]

IMO your PINPOINT is off, don't panic make sure the test you are getting is correct first before you start adding stuff. Also I don't really think you need to add the superbuffer to newly prepared water JMO. The IO instructions are just a guide. Add whatever it taks to get to the salinity you want.

 

[NateHanson]

perhaps unrelated to your pH issue, but do you test strontium? Do others here dose strontium regularly?

 

[clamm]

I do test for it although i still in the normal range.. I haven't gone outside the normal range...yet...so seems ok...but i have only put in 2 cap fulls ever...so im sure that its not something I will need to do all the time.

 

[Moe_K]

Yes, baking soda will raise the pH... that's what I use to bring the pH of RODI water up to 8.2 for freshwater dips... I also use it on my freshwater tank to bring up the pH (because the CO2 injections lowers it).

Well, not exactly true. Baking soda can lower pH.
Randy has a very detailed explanation I would link to/quote, but the Advanced Aquarist site is down right now.
I'll link/quote when the site is back up.

 

[Lam]

Baking soda LOWERS pH slightly. Washing soda RAISES pH. There are lots of good articles out there describing this and why so many people are confused about baking soda. I'll see if I can find it for you guys.


Beat me to it Moe .

 

[nunofs]

Moe, Lam, does it depend on some other parameters in the tank? Because I do definitely see a large increase in pH after dosing baking soda (both in fresh and salt water). And I'm not mistaking it for washing soda, the stuff I use is the regular Arm&Hammer baking soda. Now I'm very curious about reading those articles...

Nuno

 

[wrassefan]

http://www.advancedaquarist.com/issues/april2004/chem.htm

Randy suggests baking the baking soda to raise ph.

 

[Moe_K]

From Randy's article:

Another good option to lower chronically high pH is to switch to an alkalinity supplement that has less of a pH raising effect. Limewater is the worst of the lot, followed by sodium carbonate (washing soda). Sodium bicarbonate (baking soda) will actually have a very slight pH lowering effect on it?s own, and will make a big pH effect relative to adding limewater or washing soda. A CaCO3/CO2 reactor, of course, has the biggest pH lowering impact of any alkalinity supplement scheme (as described above).

 

[Randy Holmes-Farley]

Just to clarify a few things.

In seawater, adding baking soda will have an initial pH lowering effect. If the tank has excess CO2 in it because of the baking soda, the pH can then rise over time. Note that in freshwater, baking soda has a higher pH than in seawater. It is one of the oddities of science that one can add a feshwater/baking soda solution at pH 8.2 to marine tank water at pH 8.0 and have the pH decline in the tank water.

Baked baking soda (or washing soda) and also limewater will have an initial pH raising effect, and that pH can drop over time as the tank sucks in extra CO2 from the air.

I show those results experimentally in this article:

The Relationship Between Alkalinity and pH.
http://www.advancedaquarist.com/issues/may2002/chem.htm

Soda water, and straight CO2 addition, will reduce pH dramatically, but does not change the alkalinity.

 

[Randy Holmes-Farley]

its at 8.8 and holding steady...even after a 35% water change, it remained at 8.8. What can I do about this?

Unless you are adding limewater or a ton of another very high pH additive, that pH is almost certainly a measurement error, and I would not do ANYTHING about it without confirming it first.

If the pH is that high, aeration alone will bring it down.

 

[nunofs]

I read the article and won't obviously question the chemistry of it, but am curious why I'm getting the practical results I mentioned above, namely that adding baking soda to RODI water will raise it's pH, and the same thing happening when adding baking soda to my tank... and on both scenarios I can measure an immediate (large) increase in pH, which lasts for at least a couple of days in my tank. Is it just because there's a lot of CO2 dissolved in the water (I have CO2 injection on my FW planted tank)? Still that doesn't match the short/long term effects described in the article...

Nuno

 

[Randy Holmes-Farley]

I edtied my post above to include a freshwater discussion. Bakign soda does raise freshwater pH, but it lowers seawater pH.

I'd suggest retrying the baking soda addition to tank water. Put the pH probe into the seawater, and add a little baking soda. The pH will decline and then later may rise

 

[nunofs]

Thanks Randy, that "oddity of science" (behavior in fresh vs saltwater) explains it!

Btw, I don't yet have a pH meter, still using chemical tests.

Nuno

 

[clamm]

UPDATE! You guys were right, meter calibration issue, recalibrated and is 8.27. So thanks for the help! Sometimes we don't look for the obvious answer!

 

[Moe_K]

Woo hoo! Problem solved!

 

[clamm]

1 down...many to discover.