High PH

[timinswfl]

I noticed my water was cloudy today so I added some bleach. When I ran the full test this is the result:

PH 8.0
FC: 11.5
CC: 0.5
CH: 300
TA:120
CYA:55

I was planning on trying to lower the PH. Is this the correct first step?

Tim

 

[Patrick_B]

Hold off just for the moment...You may be showing false high with 11.5 FC
What's the FC been the last 4-5 days?

Once you answer, we will go from there.

 

[jblizzle]

The pH test will read a false high when the FC > 10ppm.

The correct steps are laid out in the ShockLevelAndMAINTAIN Process. Lower the pH first and then raise the FC to shock level.

 

[timinswfl]

I added the shock this morning that raised the FC. So I need to wait until FC drops to 10 and retest ph? FC was 5-6 the last couple of days.

 

[jblizzle]

Yes, the FC should drop first to make sure you get a good pH reading.

 

[Patrick_B]

Let it ride today, see if FC is below 10 tonight or in the morning. Re check pH then.

 

[timinswfl]

OK, our guests left so now I can get back to fixing the pool chemistry. I did not want to start a SLAM and be unable to use the pool. Here is what I tested this morning:

FC: 3.0
CC: 0.5
PH: 7.9
CYA: 40

I assume the TA and CH have not changed from last week- I did not retest them today. We have spa jets with a blower in the pool that probably has been raising PH. Also, I have been having a hard time keeping CYA up the last few months. The water clarity improved some since I added the bleach but it is still not clear. Should I lower PH then start a SLAM?

Tim

 

[Patrick_B]

Yes, add enough with pool math to get down to 7.2-7.3, and begin the SLAM.

 

[timinswfl]

I did the pool math calc, added the acid and measured ph an hour later and got 6.8! I was ready to start the slam but now I am not sure I should. It was 8.0 imo before so I don't know if I misread it or the pool is smaller than I thought. What should I do now?


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[jblizzle]

Did you have your TA set correctly in PoolMath? How much acid did you add?

 

[Richard320]

I did the pool math calc, added the acid and measured ph an hour later and got 6.8! I was ready to start the slam but now I am not sure I should. It was 8.0 imo before so I don't know if I misread it or the pool is smaller than I thought. What should I do now?


Sent from my iPad using Tapatalk

Just SLAM it. Your TA is high enough that the pH should bounce back up in a hurry anyway. And the longer you play around trying to fix everything else, the more the algae in the water will grow. Kill it. All of it. Now. Fix the rest later.

 

[timinswfl]

I put in 3 qts. Redoing the calc it looks like it should have been 3 cups. Oops. Still ok to start the slam?


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[jblizzle]

3 qts? 12 cups ... so 4 times what you should have added?

Luckily it looks like you were targeting 7.5, so it only should have dropped you down to about 6.8 ... yeah you should be fine to start SLAMing. The added bleach will temporarily raise the pH some ... and the TA is going to make it rise anyway

 

[timinswfl]

ok, I am back on the computer where I did the poolmath calc and I didn't mess up. 15000 gal, PH now 8.0, target 7.25, TA 120 and it does say 3 quarts. So I don't think I am that far off. Not sure why it was showing 3 cups on the ipad. Anyway I am adding 2 quarts bleach to start SLAM. Sorry for the confusion.

 

[jblizzle]

Oh, what is your acid strength set at? maybe that is the difference

 

[timinswfl]

I had the acid correct at 31.45%. When I checked it on the ipad I did not put all of the numbers (TA etc) and didn't realize that other things affected the ph calc. When I put all of the numbers in they match at 3 (corrected-->) quarts. I started SLAMing last night, will post an update in a few days when it is complete.

 

[ewkearns]

I've had this happen twice on new fills..... Initial test report 8.0+ and Pool Math says add 53 oz. of MA for pH of 7.2. Next test indicates 7.0-. WTH?

Last time this happened was about a week ago and it took 4.75# of Borax to get back to 7.4! If you do the Pool Math, it doesn't make sense.

Bottom line, I guess, is to dose using successive approximation rather than blind faith in having all of the variables covered....

 

[timinswfl]

One question on the SLAM- I have a spa inside the pool with 3 jets. I was thinking I probably should run the water through the spa pipes some (and maybe turn on the blower). How long should I run the shock level water through the jets? I set the timer for 15 minutes a day but I am not sure if that is enough.

- - - Updated - - -

ewkearns- yeah I guess I should have went with half of the suggested amount and retest. Too late now, cannot fix until the SLAM is over. My concern is if it is really lower than 6.8, will that cause an issue with the pool if I wait until after the SLAM to fix?

 

[timinswfl]

I have completed the SLAM (actually a couple of weeks ago but had some other issues to deal with). I retested the following today and still have a high Ph:

PH 8.2
FC: 4.0
CC: 0.0
CYA: 40

I did not retest CH and TA and assume they are still 300 and 120. I am guessing I should work on pH first and then CYA? Water is clear.

Tim

 

[jblizzle]

Definitely get that pH back into range. Raising the CYA should allow your SWG to work less ... and thus maybe slow the pH rise in turn.