Muriatic acid, pH, and TA

[RGS]

I use bleach to chlorinate my pool, and I find that I have to add a little acid once or twice a week, as the pH rises. People in these forums have said that bleach should not be raising the pH very much, but I think in my case, it may be due to aeration, since my attached spa has a waterfall overflow into the pool. I find that my TA tends to slowly decrease (my tap water has TA of 100), so I occasionally have to add some baking soda to bring it back up, when it drops to 70 or less. I'm wondering if the aeration is causing this?

(In my old days of ignorance, when I always used a chlorinator with tri-chlor tabs, I almost never had to add acid to control pH, but my TA would tend to slowly go up over time, so I sometimes had to use acid to bring the TA down.)

 

[Mr Bruce]

Tabs are very acidic, so they were lowering your pH for you.

You can let your TA drop to 50, see if that helps any. Yes, the aeration is what causes rising pH.

 

[RGS]

Tabs are very acidic, so they were lowering your pH for you.

You can let your TA drop to 50, see if that helps any.

How would that help? The usual recommendation is to keep TA between 80 and 120. I'm not too concerned about a TA of 70, but I just didn't want it to get too low. I've heard that pH can fluctuate more rapidly if TA gets too low.

I don't mind adding acid a couple times a week. My pH increase is usually such that it gets up to about 7.8, and 1 drop of the acid demand reagent brings it down to 7.4. I'll then add the appropriate amount of muriatic acid which makes the pool pH go to 7.4, and then in about 3 or 4 days, it's back up around 7.8, at which point I add some more acid.

 

[bluetahoe]

How would that help? The usual recommendation is to keep TA between 80 and 120. I'm not too concerned about a TA of 70, but I just didn't want it to get too low. I've heard that pH can fluctuate more rapidly if TA gets too low.

I don't mind adding acid a couple times a week. My pH increase is usually such that it gets up to about 7.8, and 1 drop of the acid demand reagent brings it down to 7.4. I'll then add the appropriate amount of muriatic acid which makes the pool pH go to 7.4, and then in about 3 or 4 days, it's back up around 7.8, at which point I add some more acid.

The experts here will tell you that it's ok to allow your TA to go down to 50 if that's what your pool "likes." Everyones pool is a little different and the 80 to 120 is a general rule. I keep my TA at 50 and it has been there for a long time and I still have to acid once a week as my ph still creeps up slowly-it doesn't fluctuate much at all.

 

[RGS]

Thanks. I'll let the TA go to 50 then, and see if my pool likes it, instead of getting more baking soda. I was just concerned that if TA is steadily going down, at some point I'd need to stop it.

 

[bluetahoe]

Thanks. I'll let the TA go to 50 then, and see if my pool likes it, instead of getting more baking soda. I was just concerned that if TA is steadily going down, at some point I'd need to stop it.

Definitely give it a shot and see if that works better for you. Keep some baking soda handy just in case you do need to raise it at some point. You'll find the right spot for your pool.

 

[xcrazydx]

The experts here will tell you that it's ok to allow your TA to go down to 50 if that's what your pool "likes." Everyones pool is a little different and the 80 to 120 is a general rule. I keep my TA at 50 and it has been there for a long time and I still have to acid once a week as my ph still creeps up slowly-it doesn't fluctuate much at all.

If I don't let my TA go down to 40-50 I have to add acid everyday and id be buying a gallon every other day. lol