A bit confused

[Cal_Newbie]

All righty then................

Pool is now at 90ppm TA...YIPPEEEEEEEE
pH is now at 7.0................................

Pool is still aerating and continue to do so until the pH is in the 7.4-7.6 range.. correct?

Then I can shock the pool and add in the CYA... from there, I need to keep my chlorine level at ??????

CYA, what would you guesstimate for a nice, hot, sunny California pool?

Bob-

[chem geek]

Yup, you got it. Aerate until you get to around the 7.5 pH that you want. Add CYA to around 30 ppm which should be fine. This graph shows that the biggest bang-for-the-buck comes from very little CYA. At 30 ppm, you would keep your chlorine at a target of 3.5 ppm (absolute minimum 2.5 ppm) and your chlorine half-life in direct noontime sun should be about 6 hours (so in practice that means losing somewhat less than half your chlorine level in a 24-hour period). So you might add chlorine at night to get to 7 ppm and find it down at 3.5 to 4 ppm the next evening. At 50 ppm, this half-life increases to about 7 hours, but you'd then need to have a chlorine target of about 5.7 ppm (absolute minimum 3.7 ppm) and you'd end up adding more chlorine to maintain this higher FC level.

Using a pool cover will significantly cut down chlorine usage. Using 30-50 ppm Borates may cut down the usage as well since the Borates will kill algae so that chlorine doesn't have to. Actual chlorine usage is also a function of how much junk (organic matter) gets into your pool. And of course, a pool party with lots of little kids who just can't "hold it" (or get out quickly enough) will use up a whole lot of chlorine very quickly.

Richard

[Cal_Newbie]

Arggggggggggggggggggggggggghhhhhhhhhhhhhhhhhhhhhhh

It Never Stooooooooooooooooooooops!!!!!!!!!!!!!!!! Lol

[Cal_Newbie]

Oh , one last thingy...my house water TA is 270ppm !!!!!!

Suggestions as to what to do when using the house water to fill with? Or is so diluted that I only need to add acid to adjust.

[chem geek]

If you want to avoid a slow but steady rise in Total Alklainity (TA) from your fill water, then I would suggest that you do the acid/aeration technique with your house water in a large container and then use that water to add to the pool to fill after evaporation. It is FAR easier to lower the TA of your fill water before getting it into the pool.

Of course, whether this is worth doing is a function of how much fill water you will be adding over time. If it's a small fraction of your pool water volume, then the above procedure is not worth it.

Richard

[Cal_Newbie]

When I do my bleach to shock the pool, this will give me a rise in pH, if I recall. Do I let the pH drift down or should I add acid? Friggin stuff...I breezed pharmacology, drip rates, med conversions in the middle of the night..thank goodness my patients are not pools...

[chem geek]

Bleach (and chlorinating liquid) do raise the pH when you add them, but the usage of the chlorine lowers the pH so it's really pH neutral. Don't try to add acid after adding bleach in order to get the pH just right. You'll yo-yo back and forth. Measure your pH consistently, just before you add more chlorine. Finally, if you have enough TA, the addition of chlorine will only raise the pH by about 0.1 to 0.2 which isn't very much. If you measure your pH before you add chlorine, you can target 7.4 and then after chlorine addition it will be 7.5-7.6 and will then slowly drift back down to 7.4 the next time you add chlorine.

The above scenario assumes you aren't experiencing a general rise in pH. Most pools have that and it has nothing to do with the chlorine, but rather the outgassing of carbon dioxide from your pool. Having a lower TA (say, 80 ppm) helps reduce this problem.

Richard