Really high TA w stable pH

[redceleste]

I'm new to the forum and am so thankful for TFP! It has helped me immensely as this is my first summer caring for a pool. I'm dealing with a vinyl pool with about 1800 gallons of water. I've had the pool up for about a month, and am concerned because my TA is 210. My pH has been extremely stable (7.5) the whole time the pool's been up. I read on the forum that it is more difficult to adjust pH than TA. Although my TA is so high, am I safe to assume that I should not mess with it since pH is so stable? Will TA this high damage vinyl? Here are my numbers:

FC: 6 (usually swings around quickly between 0-6)
pH: 7.5
TA: 210
CYA: Little less than 30 (I plan to add a little more dichlor to raise CYA to keep FC more stable since pool is in sun all day.)
CH: 240
Water appearance: clear
Gets lots of regular splashing from kids.

~ Celeste

 

[Richard320]

The pool calculator shows CSI is okay, so don't worry about high TA. Enjoy the free ride.

I'd worry more about FC fluctuating - zero is bad. Very, very bad. It could be the low CYA letting it burn off, or it could be the beginnings of an algae bloom. Or it could be lack of diligence on your part. Hmmmm

Using dichlor to raise CYA is a fine idea. Realize that just one pound of it in your pool will raise FC by 37, raise CYA by 34, and lower pH by 1.4. So you don't want to add it all at once, that's for sure! In fact, you probably don't want to even use a whole one pound bag because that will drive CYA to about 60. As a side benefit of lowering the pH with the dichlor, your TA will come down some.

Recommendation: use http://www.poolcalculator.com/ to calculate the daily chlorine dose and select dichlor as the source. If pH dips towards 7.2ish, revert to bleach for a few days until it recovers, then resume the dichlor. Don't forget that as the CYA level rises, so does the minimum FC level.

 

[chem geek]

Welcome to TFP!

You are fortunate to not experience a pH rise with the high TA. As Richard says, "enjoy the free ride".