ph dropped (weird) so CSI is off

Johnny B

LifeTime Supporter
Mar 19, 2009
588
Charlotte, NC
I still have my winter mesh cover on & will until end of May but I test & dose the pool anyways & hand brush for circulation all winter

12.29.2019
CH 260 Target 375 with 257 oz by volume of calcium chloride shy at 243
CSI: balanced

3.28.2020
pH 7.5
FC 7
CC
TA 50
CH 220-230
CYA 0 Target 20 so 55oz by Volume + add 3 more pucks
65° F and should be warming
CSI: potential plaster corrosion until increase pH to 7.8

I can increase pH to 7.8 ; but in all my years I never saw my pH go down (been at 7.7+ all winter, where I like it) so I wanted to ask to get your opinions before I raise the pH. In past summers/warm water/open pool it's best with TA 50 & CH 300 (In winter it's best at TA60-70 & CH 400).
We've had a ton of rain this winter but normal amounts since the last test 8 day ago.
I should get the pH up to 7.8, right? Want me to bump the CH to 300?
Just kind of weird about the pH dropping for the 1st time ever (yes the reagents are fresh) but my plaster is in very poor shape. Thank you.
 

JamesW

TFP Expert
Mar 2, 2011
19,337
Cyanuric acid will drop the pH some.

I would increase the TA to about 60 or 70 and recheck things in a few days.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Oooh, it's a shame you have to wait until May to open. :( I agree with James. Adding a little baking soda should be fine. I wouldn't try to do too much else right now though, especially without the pump circulating. Test results could be skewed just a little. In a few days see if that pH goes back to the upper 7s.
 

Johnny B

LifeTime Supporter
Mar 19, 2009
588
Charlotte, NC
4.88.2020 11days since last Test & dosing
winter level 18,463 gal
pH 7.4 ;drew test water away from puck to double check
FC 12 seems hi but CYA was added, water still cool, I'm drawing test water near pucks.
Added 5 more pucks because bleach is scarce(Coronaa)
CC
TA 70
CH 260-270 (last test was off & I thought it was)
CYA assume 20 because that’s was targeted for last time when CYA was 0-20
added 3 more pucks
65° F
CSI: potential plaster corrosion until increase pH to 7.6

Want me to do anything? I'm ok leaving it if you guys would, Just hoping to milk my plaster a bit longer. Thank you.
 

JamesW

TFP Expert
Mar 2, 2011
19,337
It will raise the pH some, which should get you into the good range.

Tabs are acidic and you need the higher TA to neutralize the acid.
 

Johnny B

LifeTime Supporter
Mar 19, 2009
588
Charlotte, NC
Thank you. I happened to score some free tabs (otherwise I never use them ), figured why not use them early season when CYA is low/zero & I can't open for a while.
 

Johnny B

LifeTime Supporter
Mar 19, 2009
588
Charlotte, NC
To repeat:

- I still have my winter mesh cover on & will until end of May or maybe even later but I test & dose the pool anyways & hand brush for circulation all winter so doing the same now.

- in all my years I never saw my pH go down; Cyanuric acid will drop the pH some; happened to score some free tabs (otherwise I never use them ), figured why not use them early season when CYA is low/zero & I can't open for a while.

- CSI: potential plaster corrosion



5.5.2020

(winter level 18,463gal):

pH 7.3-7.4 Target with __ oz of 31.45% muriatic acid

FC >10Target 8 so oz 6% 8.25% Bleach

TA 70-80 Target __ with __ oz by weight volume baking soda

CH 230 Target with oz by volume of calcium chloride

CYA CYA assume 20 because that’s was targeted for & FC holding, a non-issue

68° F

CSI: potential plaster corrosion



Want me to take TA to 90? Or raise the CH?

Thank you.
 

JamesW

TFP Expert
Mar 2, 2011
19,337
I would keep raising the TA as needed to keep the pH and CSI good.

Once you open, you can address the chemistry balance as needed.
 

Johnny B

LifeTime Supporter
Mar 19, 2009
588
Charlotte, NC
How should I handle not opening?



For a variety of reasons I'm not gonna be able to open the pool this season/summer.

I'm used to treating the pool all winter long with the mesh cover on, the pump not running, dosing it with chlorine and whatever else it needs which is usually nothing because it is properly closed/winterized in the fall.



So now I need to treat the mesh-covered pool without a pump running all summer long which obviously is more of a challenge than during the cold winter.



To date, I have indeed been treating it with about weekly tests and dosing with the appropriate chemicals. I assume I should keep doing this all summer long? The reason I ask is because on one hand obviously the pool is not to be used for swimming so in that regard one could just let it go to a green swamp and deal with it at the next spring opening. On the other hand, it makes sense to keep the water reasonably balanced for the health of the plaster etc (the plaster is in bad condition and needs to be replaced but I'm going to get away with crummy plaster for as many years as I can).



Do you guys recommend I keep treating it, trying to maintain reasonable chemistry/conditions? The water is clear (TC was never below 4) but obviously there's algae in the pool/visible green at some places in the plaster up high where the water level varies before gets dropped back down with the sump pump.

It really is up not that much trouble for me to treat it because I do it all winter long every winter.



Here are the latest test results

6.18.2020

pH 7.4

TC 4

TA 70

CH 180

CYA 40

water temperature 72°F and of course that's gonna get hotter as summer proceeds but with the mesh cover on it is remaining cooler than it otherwise would be

CSI corrosion of plaster likely



That lower pH creates a problem for the CSI, this low pH issue was the concern of my original post in this thread, I was using some free pucks up and figured why not get the CYA early in the spring when I knew that the CYA was probably zero; there are no more pucks from this point forward.

I did indeed get the TA up to TA 90 as recommended above and the TA has since fallen to 70 today, so no big deal for me to get the TA back up to 90 if that is what you think I should do?

I can get the CH up there also no problem if you think I should?

If you guys think I should treat the pool all summer long, what targets should I shoot for with TA & CH?



How would you guys handle this, treat the covered pool the best I can all summer or forget it let it go green?



Water level question: no sense letting the water get to the tile line unless rain gets it there, right? That level (just below the where the tile starts) still gives the pool plenty of structural support, but no sense having the water higher than that for a variety of reasons and because it is very easy to lower with the sump pump, right?



Thank you