Proper CYA and Ph levels for me?

[SemperFly]

After a recent drain and acid wash, I took over my own pool mx and it's been great so far. It's a 30 yr old, pool, but I've only owned it for seven mos. The previous ownership was pretty lazy and relied on tabs and a pool service...the CH and CYA were off-the-charts high. All my reading on TFP indicates that I should be very careful about additions of conditioner, so I've deliberately only allowed it to get to btwn 40-50ppm since the refill...I figure it's much easier to add more, if needed, than to remove it. I live in S.California and my pool is in a very sunny location (in direct sunlight, nearly all day).

Question #1: Is 40-50ppm CYA enough for this amount of daily sunshine? My normal FC consumption seems to be 3ppm every 2-3 days...I seem to be adding approx 64oz of 10% liq CL every 2-3 days to bump it up 3 ppm.

Another thing I'm trying to get a better understanding of is PH management. My pool has an attached spa that is elevated 2-3 feet above the pool water level. When the pump is running, the spa water spills over into the pool to be recirculated. It really just flows down the face of the spa, as opposed to being like a waterfall. I've been trying to keep my PH in the 7.6-7.8 range, via lig acid additions, but it seems to want to climb right back up to 7.9-8.1 after just a week, or so. According to my chemical addition tracking, I've been adding approx. 32oz of 20 baume (31.45%) MA, weekly, to knock the PH from 8-8.1 down to 7.6...2 drops on the acid demand test and using the Taylor-recommended additions. Is this a normal amt of MA to be adding, based on my pool description?

Thanks!

 

[Texas Splash]

Question #1: Is 40-50ppm CYA enough for this amount of daily sunshine? My normal FC consumption seems to be 3ppm every 2-3 days...I seem to be adding approx 64oz of 10% liq CL every 2-3 days to bump it up 3 ppm.

That seems to be working great. We hope to keep FC consumption under 4ppm in 24 hrs, and you're doing much better than that already.
For the pH, it would help to know your TA. If your TA is elevated, you can try lowering the TA following the TFP Pool School - Lower Total Alkalinity page. For example, if your TA is over 100, try lowering to about 80. If it's at 80, try 70, or even 60 and see how well that works to keep the pH from climbing so fast. Just go in stages until hopefully you find a sweet spot that keeps the pH more stable. Remember new fill water may have a tendency to increase TA, so it's always something that requires a look every few days.

 

[SemperFly]

Great news on the FC question!

After the refill, my TA was 120ppm. After a few weeks, it climbed up to 130, so I knocked it down to 100...it's been btwn 100-110 for the past month.

 

[SemperFly]

In your opinion, would an avg of 32oz of 20 baume MA per week be considered in the 'normal' range to be added to a pool of my size, to maintain the PH in range, or would that amt be an indicator of some potential issue?

 

[Texas Splash]

The only issue with it really is inconvenience and expense. Our pools are close in size, and unless I'm trying to do something specific, my normal acid requirement may be about 1 cup a week or so - maybe two at times. But so much depends on the current TA level (higher TA = faster pH rise) and evaporation since most new water will increase TA as well. Since your TA has been at about 100 for a while, I would try knocking it down to about 80 and see what impact that has on your pH's tendency to rise.

 

[SemperFly]

OK, thanks...I might give that a try and see what happens. Although, before I do, do you think the aeration from my simple spillover from the spa into the pool would be enough to continually raise the PH up that quickly? I don't see any water features listed in your sig.

 

[Richard320]

Set aside a day when you'll be around. Dose to 7.2 pH and then run the spa full tilt, as much aeration and spillover as you can. When I did that, the pH came up to 7.8 in about 4 hours. Do it a few times. People can still use the pool while you're doing it, by the way. Once I finally got my TA down to to about 60-70 it holds a lot better. I add about a quart of acid a week, usually just because I added water.

 

[SemperFly]

Thanks for the response and the tip, Richard...I may do it tomorrow!