pH has been increasing - why?

[trigirlCT]

FC= 4.5
CC=0
pH = 7.8
Alkalinity = 100
Calcium hardness = 160
CYA = 40

My numbers are all good, and water is clear. My husband thinks I over analyze the pool numbers but I can't help but wonder why? I have noticed that the last few weeks my ph has been on the rise. Started at 7.2 then 7.4 several days later, then 7.6 maybe 4-5 days later, and now about 2-3 weeks into it is up to 7.8.

I test the water every 3-7 days ...after heavy use I always test and make adjustments. Have only added chlorine to the pool the last 3 weeks. I chlorinate with pucks and have always found that pH would need to be raised over the summer (pucks are acidic and decrease the pH). Alkalinity has remained 100-110 range and no changes to any of my numbers. I keep chlorine between 3-5pm. I haven't filled my pool since the start up because the rain this summer has kept our levels good. I actually had to drop the water level at one point and did need to do a backwash.

I know everything is in normal ranges and I should just let it be but....Any reason pH would just start raising when everything else remains the same? Anything I should be on the look out for? Thanks

 

[jblizzle]

Your signature says you are not using pucks, but then above you say that you are ... which one is it?

Using pucks, you are right the pH will tend to drop.
Using bleach, with a higher TA like you have, the pH will always tend to rise. That is pretty normal.

 

[trigirlCT]

Sorry for the confusion. I changed the signature. 3"pucks are used.

New bucket of pucks that husband wants to use. We compromised on if the CYA got to 50, we switch to liquid chlorine. We use about 1.5 pucks weekly. I use liquid bleach for the out of norm things (drop in FC below our range or the one case when we had to SLAM this yr because pucks weren't added to the chlorinator!).

 

[jblizzle]

A little odd that with the pucks the pH is rising, but I would not complain about having to add a little acid every 3 weeks

 

[easttn]

3 weeks without adding acid is not bad at all. Are the tabs composed of Trichlor or Calcium Hypochlorite?