pH jums from 7.6 to 8.2 every day

[Michigandad3]

I just started the BBB method with liquid chlorine (10%). My readings for the past 2 days are:

Date	30 Aug 2018	31 Aug 2018
FC	3	3
TC	3	3
PH	7.6	8.2
Alkaline	140	170
CYA	40	40
CH	130	130

I will add muratic acid to get the pH back in line, but why is it changing so much every day? It has done this for 3 days in a row.

 

[YippeeSkippy]

Your TA is high, which pulls the pH up. Try lowering your TA and see if that slows things down- Pool School - Lower Total Alkalinity

Do you have any water features? Those will cause pH rise.

Is this a new pool that is still curing? The plaster can take many months to cure during which time the pH is always rising.

Make sure you're using the right strength of MA when you input the numbers in to PoolMath. THere is a weaker strength on the market which you may have picked up accidentally.

Maddie

 

[Catanzaro]

What kit are you using? Your TA jumped 30 in one day? Regardless, lowering TA will be a weekly event until you reach a level that stabilizes the PH.

 

[Michigandad3]

What kit are you using? Your TA jumped 30 in one day? Regardless, lowering TA will be a weekly event until you reach a level that stabilizes the PH.

I am using a TF-100 kit, and I have a small waterfall. The pool is approximately 10 years old, but I drained it 5 days ago to lower the CYA. After draining, I used ascorbic acid to eliminate iron stains, then I brushed thoroughly, and added a bottle of metal free.

 

[Michigandad3]

I am using approximately 64 ounces of 10% liquid chlorine and 64 ounces of 31.45% muratic acid per day.

- - - Updated - - -

What kit are you using? Your TA jumped 30 in one day? Regardless, lowering TA will be a weekly event until you reach a level that stabilizes the PH.

So I should use muratic acid every day to lower pH to a 7.0, and eventually it will stabilize?

- - - Updated - - -

I forgot to mention that I am in Houston, with approximately 8 hours of direct sun, and temperatures in the mid 90s. The water temperature ranges from 89-92 this time of yerar.

 

[Catanzaro]

Your TA is high, but also are you testing for PH after adding liquid chlorine? When are you adding each, and when are you testing as well? The waterfall will create aeration and raise your PH as well. You may want to shut off your waterfall for now until your TA is lower, and your PH does not drift up this quickly. Although, adding acid will lower PH and TA slowly. It took over 1.5 years to get my TA from 130 to about 70 and acid was needed every 4 days.

Test 24 hours later for PH, before adding any liquid chlorine to see where your levels are. If you find that PH rises this fast, bring to 7.2 until it reaches 7.8 and then repeat the cycle. Also, is the plaster new or the same from 10 years ago?

 

[Michigandad3]

I am testing approximately 2 hours after adding the muratic acid and liquid chlorine, and levels are correct. I test again 22 hours later, and FC is low and pH is high. This is the same plaster (pebblesheen) from 10 years ago.

Thanks for all the advice.

 

[Catanzaro]

I am testing approximately 2 hours after adding the muratic acid and liquid chlorine, and levels are correct. I test again 22 hours later, and FC is low and pH is high. This is the same plaster (pebblesheen) from 10 years ago.

Thanks for all the advice.

Then you must run the normal course of lower TA the old fashioned way! Muriatic Acid.

 

[JamesW]

It's odd that the TA seems to have gone up by 30 ppm. Maybe testing error?

If it really did increase, then something basic got in the water. Maybe plaster dissolving?

The calcium is low. You should increase that to try to get to a CSI of about -0.3 to 0.0. That will reduce plaster dissolution.

If you're using tabs, then that will lower the pH and TA over time.

Are you using tabs?

Have you added cyanuric acid?

 

[Michigandad3]

When I drained my water a few days ago to lower the CYS I switched from tabs to liquid chlorine. Yesterday evening I added muratic acid, and the pH was 7.4. This morning, the pH is 7.4-7.5. Your comment on the plaster scares me. When I run my vacuum, I also get a handful of blue pebbles from my pebblesheen. I will work on the CSI.

Thanks to all of you with the very helpful advice.

 

[triptyx]

Your TA is high, but also are you testing for PH after adding liquid chlorine? When are you adding each, and when are you testing as well? The waterfall will create aeration and raise your PH as well. You may want to shut off your waterfall for now until your TA is lower, and your PH does not drift up this quickly. Although, adding acid will lower PH and TA slowly. It took over 1.5 years to get my TA from 130 to about 70 and acid was needed every 4 days.

Test 24 hours later for PH, before adding any liquid chlorine to see where your levels are. If you find that PH rises this fast, bring to 7.2 until it reaches 7.8 and then repeat the cycle. Also, is the plaster new or the same from 10 years ago?

No, the OP should leave the waterfall on while lowering TA - the waterfall will assist in raising pH faster, allowing it to be adjusted back to 7.2 with a corresponding reduction in TA more quickly than if the waterfall is off. No need to wait until pH is 7.8, lowering from 7.6 back to 7.2 should work very well to lower TA. The key is staying on top of it and lowering it often.

 

[JamesW]

If you're getting a lot of pebbles coming loose, that indicates that the cement is dissolving some. Cement raises ph and TA when it dissolves.

Getting the CSI up some should help.

 

[Catanzaro]

No, the OP should leave the waterfall on while lowering TA - the waterfall will assist in raising pH faster, allowing it to be adjusted back to 7.2 with a corresponding reduction in TA more quickly than if the waterfall is off. No need to wait until pH is 7.8, lowering from 7.6 back to 7.2 should work very well to lower TA. The key is staying on top of it and lowering it often.

Triptyx:

In total agreement with you, but a jump of this nature in one day, I figured this would give him a break for a few more days. I guess no matter what works needs to be done and the pool will need to be babysat.

 

[Michigandad3]

Thanks for all the advise! I adjusted the calcium, and dropped the pH to 7.2, and this past day the pH did not move! Lets hope the number of pebbles falling off reduces.

 

[Catanzaro]

Thanks for all the advise! I adjusted the calcium, and dropped the pH to 7.2, and this past day the pH did not move! Lets hope the number of pebbles falling off reduces.

Maybe you were testing while chlorine was high. Keep track of results, exact time, exact readings, exact additions. This way you can determine how many days before PH moves back up.

Where exactly is your TA at the moment? Your PH is 7.2. Thanks!