TA, CYA, and pH struggle

[CavVet]

Yesterday's test results:
FC: 5
CC: .5 (or less)
TH: 380
TA: 50
pH: 7.4
CYA: 50

First, thank you for such a great service to pool owners! i have had some issues this summer with low CYA & TA, and rising pH.
Yesterday i (again) added some granular CYA to increase this.
now...on to TA and pH...these two seem to be battling each other. i've added muriatic acid nearly daily to keep pH to 7.4-7.6, which seams to be lowering my TA. I had TA around 60-80 in early July, but it continues to creep down.
I added some baking soda yesterday to increase the TA, but i know that i'll find my pH going up as well.
I am beginning my third year of ownership (pool came with home purchase). I was using test strips (exclusively) until June when i purchased a Taylor K-2006. which i am using daily (for pH).
my chlorine generator is set to 35% and is keeping up just fine. i am also dealing with scale, but now that i am testing properly for pH, it doesn't surprise me that i had scale formation.
in addition, i plugged my overflow drain and shut off my fresh water supply to see how much water i am losing...which is negligable. however, i was losing alot of water out of my overflow, because my fresh water float was sticking....and constantly adding fresh water....i suspected this when my water bills went through the roof.

any guidance on managing pH and TA together? could this work itself out now that i'm not dumping water?

 

[RussellC]

If those numbers are accurate you should let your pH rise until it settles. No reason to keep it at 7.4-7.6 if it likes to stay at 7.8, which is where most SWG pools like to settle. With a TA at 50 your pH rise will likely slow as it gets higher but it will be nearly impossible to keep at 7.4. Did you test salt? At 3200 and if you got your CYA up to 80, then you are not going to get any scaling. Your CSI will be nearly -0.3.

 

[CavVet]

If those numbers are accurate you should let your pH rise until it settles. No reason to keep it at 7.4-7.6 if it likes to stay at 7.8, which is where most SWG pools like to settle. With a TA at 50 your pH rise will likely slow as it gets higher but it will be nearly impossible to keep at 7.4. Did you test salt? At 3200 and if you got your CYA up to 80, then you are not going to get any scaling. Your CSI will be nearly -0.3.

My pH is rising about .2 per day and seems to rise to 8.0 which is what my testing kit maxes at.
my salt tested at 3,400. (although we've had alot of rain in central texas last two days....so it may be diluted a bit).
I will get my CYA increased and see where it settles.

 

[kcindc]

Do not increase your TA. The only time you should adjust your TA is if you are having a hard time controlling your PH. With a SWG, you PH will rise. However, keep adjusting your PH down to 7.2 each time you add acid and hopefully you will finally get your TA to a point that your PH won't rise very much.

Any flow overs, water falls, bubblers, etc. cause aeration and will also increase your PH, so try to keep those down to a minimum.

 

[CavVet]

Do not increase your TA. The only time you should adjust your TA is if you are having a hard time controlling your PH. With a SWG, you PH will rise. However, keep adjusting your PH down to 7.2 each time you add acid and hopefully you will finally get your TA to a point that your PH won't rise very much.

Any flow overs, water falls, bubblers, etc. cause aeration and will also increase your PH, so try to keep those down to a minimum.

Until today, i've been adding 1 1/4 cup of muriatic acid (daily) to keep pH around 7.4, only because i read that it was around the same pH for human tears. I have alot of kids using the pool and wanted to cut down on the 'red eye'. if i don't raise my TA, it seems my CSI will be corrosive. do you agree?

 

[RussellC]

Leave it alone and let the pH rise to above 7.8 until you add acid. If you are in Central TX like me, your fill water will make the TA rise anyways. Test your fill waters TA. I think if you are anywhere between -0.3 - 0 you will be fine. It is preferred to be in the negative range for a salt pool.