Worried about CSI. High TA but low PH.

bostonpool

Well-known member
May 29, 2017
105
Worcester, MA
Hi folks.

I opened my pool by myself this year. A first! All went well and the pool looks good. I'm now dialing in the chemistry.

I've got a concern because right now my CSI for my Gunite pool is -0.44. I want to get this lower.

Right now I'm at:
FC=13 (still reducing due to SLAM)
PH = 7.4
CH = 400
TA = 75
CYA=65
Borates = 15
Temp = 70 deg
Salt = 3500

The best way to get my CSI in line is to either raise CH or raise PH. I'm all out of calcium chloride and won't get any until a week from now. So raising CH more is out for at least the next week.

I can raise PH by adding Borax, but my TA is already on the high end and I don't want it to go up any more. I know I can aerate the water...but I don't have eyeballs on the returns, although I do run a SWG.

THoughts on the best way to proceed? SHould I just hang in there and wait for calcium chloride to arrive and increase CH a week from now? Or should I immediately go out and add Borax to increase PH knowing it will screw my TA? Or just wait over time for PH to rise slowly due to SWG.

How big of a deal is -0.44 CSI?

Thanks
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,540
Laughlin, NV
I would not do anything. Let the pH rise from natural aeration. Warmer water will increase the CSI too.

Not really sure you need to track CSI in your area. But up to you.

What is the CH and TA of your fill water? And how much fill water do you use during the summer?
 

bostonpool

Well-known member
May 29, 2017
105
Worcester, MA
Thanks!

I use my hose to fill my pool when it needs it. Usually about 1x / week. We are on a well. No idea of the CH and TA of my well water, but I can check.

Why don't I have to worry about CSI in my area? Is there an area where it is more important than others?
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,251
Sebring, Florida
Why don't I have to worry about CSI in my area? Is there an area where it is more important than others?
Yes. Primarily the desert Southwest, Texas and some parts of California. Their high CH content of their fill water, rapid evaporation make it VERY difficult for those pools to stay within the TFP guidelines without some special attention to CSI.

Those of us in most of the rest of the country can simply keep our five parameters for which we test within the ranges suggested by TFP and Calcium Scale is just not a problem. Pretty safe to say that no one on the East Coast has to calculate CSI. That doesn't mean you won't get some evaporative Calcium deposits around your water line tile or a waterfall but that's due to evaporation.......not the saturation of calcium in your water which can form scale on your entire pool surfaces.
 

bostonpool

Well-known member
May 29, 2017
105
Worcester, MA
Oh OK. Did not know that. I've been worrying my plaster was going to corrode or crack if CSI got too out of whack.

They should mention this in Pool School. All it says is to monitor CSI if you have a plaster pool.

Thanks!