To Calcium or Not to Calcium..

[mcinlb]

Had to drain our pool in April for a repair to a swim up bar and ran water chemistry tests on our newly refilled pool (5/15/2019) with the following results:

FAC 5
TAC 5
Salt 3000
CH 230
CYA 70
TA 100
pH 7.8
CSI @ 65 degrees (per PoolMath Calc) is -.18

Did some reading on pool school and it was recommended to have the CH between 350-450. How critical is the addition of Calcium Chloride in this situation? Thank you!

 

[Texas Splash]

How critical is the addition of Calcium Chloride in this situation?

Leave it where it is. You probably have enough hard water in your area, so the last thing you need is to add more. If your numbers above are correct, they look good. The CSI is fine. There may be a TFP recommended level CH change later this season anyways, so no worries.

 

[mcinlb]

Thank you for your insight!

 

[hb-]

There may be a TFP recommended level CH change later this season anyways, so no worries.

Where can I find out more about the possible change? Are they lowering the range?

 

[Texas Splash]

Where can I find out more about the possible change? Are they lowering the range?

There has been a suggestion to expand the CH level (slightly lower) for certain pools. That suggestion is still under review and not published as official guidance as of yet.

 

[Teald024]

Regardless of a potential modification of the TFP guidelines, you would want to adjust CH only if it benefits your pool.

At this point, we still recommend that YOU not add any chemicals to increase CH. Your fill water and evaporation will likely cause your CH to increase on it's own. As the water temp comes up, it will also help. Keep your pH on the higher side (7.6-7.8) and you will have nice balanced water and not need to adjust CH.

 

[Jimmy Marinos]

When I refilled my pool in December 2017, my CH was at 175. I adjusted the CH with CaCl2 to 225 and then kept my pH high at ~7.8. In 5 months my CH was at 300. By July 2018 (7 months) it climbed to 400. In 2019 my CH is now >550. I try to keep the pH at 7.4 - 7.6 now. Now I have left over CaCl2 that has no purpose. It was a good learning process to use the CaCL2 (Calcium Chloride), but I probably could have gone without it those first few months and just let the pH stay high and wait for the water to evaporate. Not sure if it would have been ok to target 7.8 - 8.0 at that time and go without adding the CaCl2? I live in a hot climate - California Central Valley. {Note - I also switched to BBB after the test of 175 on the CH. After adding Borax my CH dropped to 150. I added the CaCl2 two weeks later to get to 225.] I know this is an old post, but I thought it would be good to share my experience.

 

[s_dubb]

So your saying your Calcium Hardness dropped by adding Borax?

 

[Jimmy Marinos]

Yes, based on the Taylor test kit. I trust the procedure, since I had done the CH test 20+ times by then. [The CH test was my first clue that I had a small leak in my pool. Very happy I purchased the test kit.] I would like to understand the chemistry behind the drop in the CH reading after adding the Borax, but 25 ppm is not a big difference. Maybe the extra sodium from the Borax changes the performance of the test? It is one sample and one test, so really hard to make any sort of firm statement on the test reading. I will test for CH before and after adding borax the next time, but I hope it will be a long time before I need to add 7 boxes of Borax again! I am trying to convince my neighbor to switch to BBB, so I may get the chance.

 

[mknauss]

Adding borax does not change the level of CH in pool water.