PH keeps increasing...

[Bbellz]

In early June this year we had our pool renovated including new plaster, coping and tile. I'm following the TFP method adding bleach daily, testing ph and chlorine daily and the full battery of tests 2x per week.

im adding about 64oz of muriatic (31 baume) about every 2-3 days to bring the ph down. The ph creeps up to 8.0 and then I bring it down to 7.3-7.4.

Is it normal for Ph to still be increasing when my pool plaster was completed 3minths ago? Any suggestions would be appreciated.

Here are my latest test results using the TFT100 kit:

FC 4.0 TC 4.0. CC 0.0
ph 8.0
calcium 350
TA 80 (I eg been bringing this to 90 when it drops below 80)
cyh 35

Thanks in advance!

 

[Texas Splash]

Yes, as noted on the TFP Pool School - Start-up New Plaster page, new plaster will consume a lot of acid in the 6-12 months as the plaster continues to cure. The fact that you have also been raising TA to 90 on a regular basis may also be pulling the pH as well since TA serves as a buffer for pH. Using the Poolmath calculator , you may wish to examine the thought of allowing your TA to rest a little lower which may in-fact help keep your pH from rising so fast. Compare the CSI range on the calculator to ensure you're still within the -0.6 to .6 acceptable ranges as applicable. And don't forget that any aeration you may have (if any) will also contribute to elevating pH. Hope this helps.

 

[pooldv]

+1 to letting your TA drop. As low as 50 or 60 is fine and it will help to stabilize your PH. It is important to keep your PH between 7.2 and 7.8 at all times in all pools. It is very important to keep it at 7.8 or lower in newly plastered pools. It can take up to a year for the plaster to fully cure.

 

[duraleigh]

+2 Let your TA drop 50-60 is fine.

 

[three4rd]

I might add that it can take even longer than a year for the new plaster. My pH is still going up and it is now just about 14 months since it was replastered. Unless my increase is now due to some other reason. Being that noone else mentioned this yet - I might suggest to continue monitoring the pH during the off-season. I used to pull my winter cover back partway every few weeks, check the water, add diluted dry acid, and then agitate the water around real well (kayak paddle worked great). Then recheck again in a few days or so. I had to keep lowering the pH until I couldn't any longer due to the water eventually freezing. Even then one time I punched through about an inch of ice just enough so I could get some water and test it. In retrospect I'm really not sure why I bothered to do that since no matter what the reading was I could not have done a thing about it anyway!! Just overly paranoid about developing scale I suppose. If your new plaster is ever going to scale, it is generally during the first winter following a renovation. As was already suggested, it is important to check your overall CSI.

 

[Bbellz]

Thanks everyone for the advice.