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cygnusecks
05-22-2006, 10:33 AM
All,

I am preparing to seal my paver deck around the pool. Yesterday I applied a solution of "Behr Concrete Etcher & Rust Remover No. 991" to my deck to clean it/dissolve efflorescence and during rinsing a good deal of it was rinsed into the pool. It took 1.75 gallons of the product to finish the job, and I figured it would lower my pH since I would guestimate maybe a 3/4 gallon probably ended up in the pool. Pool is 14k gal inground pebbletec/gunite pool.

After a few hours or cleaning up and running filter, pH tested normal at 7.6 (i.e. no change). I was a little surprised. My Alk level is 100. Does this sound unreasonable that the pH wouldn't change after 3/4 gal of phosphoric acid was dumped into the pool?

The MSDS for this stuff is at

http://www.msdsvault.com/msds_customers_external.cfm?aa=261&ac=JDSF76854LKJAD8960-SFJ0-AO0GWO089887RHNFBJNAOPIGAeghPPFDHPAPOREGHAPHK&ad=pjuoikltisklJ64ujudt54768w4u5NAOPIGAiopilklfdgs iihreg954&ab=991

It is 30-60% Phosphoric acid.

waterbear
05-23-2006, 02:27 AM
Phosporic acid is a mild acid but the main reason that is probably didn't affect your pH is that is was neutralized by the calcium carbonate 'efflouressence' that it dissolved which is mildly alkaline. Therefore the water that washed into the pool probably had some calcium and some phosphates in it but was near a neutral pH.

cygnusecks
05-23-2006, 09:50 AM
Ah, cool, makes perfect sense waterbear. Great, just what my 500ppm CH-level pool needs -- more calcium!! :-) Soon as I get an accurate read on CH using my PS234 which is theoretically on order, I'm gonna fix the CH level and bring it down some. I'm not sure it's great for the gas heater!

waterbear
05-23-2006, 05:11 PM
Depends on what you TA is at. If it's at the low end of the recommended range and the CH not above 500 ppm AND you have no visible scaling happening then you might be ok.