# Thread: CH=150, CSI=0, ok to close?

1. ## CH=150, CSI=0, ok to close?

Hi - big fan of TFP and really appreciate the expert advice here....

Just checking before I close the pool this weekend.
CH =150
pH = 7.8
CSI = 0.0 (Poolmath)
FC = 5.4
CC = 0.0
TA =100
CYA = 30

I know ideally CH should be higher but I've kept it this way because the previous owner left a lot of calcium deposits on the surface of the plaster.
Another factor is that the pH in this pool always wants to climb to 7.8 - 8.0. I have repeatedly tried muriatic acid and dry acid, which reduce pH, but after a few days it just climbs back up to 7.8 - 8.0!

What are the risks of leaving the water as is for the winter (covered with mesh safety cover)?

Thanks,
Steve

2. ## Re: CH=150, CSI=0, ok to close?

Can't answer the CH question (sorry) BUT do see what might be causing your PH to jump so hard. Your TA is listed as 100. If you bring that down to 80 your PH might stop jumping so fast. Each pool is very different so you might have to play with your TA to find what YOUR pool likes. Once you find YOUR TA you should see the PH level out.

Kim

3. ## Re: CH=150, CSI=0, ok to close?

In Pool Math, what do you currently have the temperature set at? How does the CSI change if you lower the temp to 32 degrees? If that number is still above -0.6, you should be fine. Bumping the CH up and lowering the TA a little next spring wouldn't hurt, depending on your pH stability this summer.

4. ## Re: CH=150, CSI=0, ok to close?

Yes, what JV says. Temp impacts CSI. The risk is etching of your plaster. Etching is when calcium dissolves out of the plaster into the water leaving a rough and pitted plaster surface. What is the CH of your fill water? I would probably raise CH to 250. More about etching here, Pool School - Calcium Scaling

Pool School - Recommended Levels

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•