I read some of your Ph discussion

[Madty]

But I'm still confused. I checked today- TA is 80 and ph is around 7.5. Is that ok? Some say go TA to 110 others saystay there. My CYA is only around 30. Should I also raise this for better protection of my CL?

Thanks

[chem geek]

But I'm still confused. I checked today- TA is 80 and ph is around 7.5. Is that ok? Some say go TA to 110 others saystay there. My CYA is only around 30. Should I also raise this for better protection of my CL?

Thanks

I'm sorry your confused. A TA of 80 is fine and a pH of 7.5 is also fine. Is there any particular reason why others are saying to raise the TA to 110? Did you mention any specific problems? I think the 80 will work fine for you. Generally, the only reason you would want to use a higher TA would be if you were using Tri-Chlor tablets (which are very acidic) as your chlorine source (which is not a good idea).

As for CYA, the irony is that you don't want to use too much because even though it will make your chlorine last longer, you'll have to have a higher Total Free Chlorine (FC) level at the higher CYA level to maintain adequate disinfection and to prevent algae growth (see Ben's CYA/FC Chart). Nevertheless you probably have some sort of chlorine usage per day already so you can't take your CYA too far down or you will run out of chlorine during the day (I assume you do not have a salt water chlorine generator since your CYA isn't high enough for those devices). At the extreme of no CYA, you technically only need 0.05 ppm or so FC, but as you can imagine, there is no way you could possibly maintain such a low level of FC everywhere in your pool, so you need enough CYA as a "chlorine buffer" to hold chlorine in reserve to last as long as you need (i.e. until the next time you add more chlorine to your pool).

With a CYA of 30, Ben's chart says to have from 3 to 6 ppm of chlorine. If you added chlorine at night to get to 6 ppm, does it only go down to 3 ppm by the next night? If so (or it goes down by less to stay above 3), then you've got the right amount of CYA. If it goes down below 3, then you may need more CYA and you will then also need to add more chlorine. You'll end up using more chlorine per day, but you'll never get below the "Min" amount and that's the most important thing.

Richard

[Madty]

Thanks for the info- I have a SWG pool system and it tends to make PH drift up, until I add acid. I was thinking that a higher TA may make the pf more stable. However, I'm sure the SWG will make it more difficult to maintain a good level.

[Watermom]

You may find that if you raise your alk a bit it may help your ph be more stable. Won't hurt to try and see.

[chem geek]

I know I'm the one who brings up counter-intuitive stuff, but lowering the TA could actually help slow the rise in pH if a large enough component of it is due to ougassing carbon dioxide. So it's hard to tell what's the best thing to do except to experiment (unfortunately, it's hard to lower TA once you've increased it). This is part of the reason it may be helpful to add borates to your pool to have an additional pH buffer with boric acid. Some others on this forum are trying that, so far successfully (see this thread for more info).

Richard

[medvampire]

I agree with Richard about lowering the ALK but for diffrent reasons. I think the outgassing of CO2 is a major player but not the only player. I feel each pool has its own buffering based on the water in the aera, filtration system, and environmental factors.
I found running my ALK around 60 to 70 reduced my acid use to about 1 pt a week from a little over a 1/2 gallon a week
Just remember our pools are diffent and your pool may need a diffrent ALK for a stable pH.
Steve