ques's on TA, Acids and pH

tstex

Silver Supporter
Aug 28, 2012
1,578
Houston, TX
Hello to all,

In another thread, I was posting my most recent [today-3/18] pool readings.

Although my CSI is -.25, I noticed that to get it to a more neutral number of "0", I would have to raise my TA from 70 to 100-120, and or lower my pH from 7.5 to 7.8. However, when I have the pool in a near [winter] equilibrium btw not having to add any MA for weeks, that a great thing, However, it means that my TA is usually 50-55 and this usually puts my CSI in the higher (-) range ie, -35+.

My TF-100 kit states "the good range" for a CL based pool is a TA of 100-120. However, that would mean adding tons of MA to keep my pH down, thus I would be fighting the game of keeping my pH & TA in equilibrium. Is there anything else I can do to raise my TA and keep my pH in a 7.5-7.8 range w out adding tons of MA and keep a higher TA level, maybe in the 85-95 range? Also, I know the dynamics of Winter Chemical Maintenance [WCM] is much diff than SCM w way diff temps, CYA needs for FC optimization and other.

I would appreciate your help on this. Thank you very much and pls let me know if you have any questions?

Regards, tstex
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,162
FL panhandle
We have revised TA recommendations downward. More here, Pool School - Recommended Levels

CSI anywhere from -0.3 to 0 in a saltwater pool is perfect. A little less in winter is fine, up to -0.6. In a non-saltwater pool anything from -0.3 to +0.3 is perfect and -0.6 to +0.6 is fine.

TA in a saltwater pool is usually good 50 to 60. Non saltwater is good 60 to 80.
 

tstex

Silver Supporter
Aug 28, 2012
1,578
Houston, TX
Thanks p-dv....I guess I'm right there in the sweet spot w -.25 and TA = 70.

Since you're from the DFW area, what are your pool temp's up there? [providing you are not either heating your pool or running your spa a lot that empties into your pool].

I'm still wrestling w the TA, acid, ph topic, and will be more so when it really starts to heat-up. It would be great to not have to add acid but every 3-4 weeks, thus keeping TA as high as possible, a better CSI and not having to add sodium bicarbonate as often...

THanks again,
tstex
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,162
FL panhandle
I am heating the pool so we were at 83 yesterday afternoon. Generally, a pool will be at the midpoint between lo and hi temp. So, lo of 60 and hi of 80 will give a pool temp around 70.

TA will push PH up until it doesn't anymore. It will stop at some point. Lowering TA by 10ish until your pH stays at 7.8 is usually the best scenario for most folks in the south-southwest. Most people's pools will do fine with TA as low as 50. You know TA is too low when your pH becomes erratic, jumping up or down with minor inputs. 40 is most commonly too low for most folks.

Yes, you are in a good place right now with -0.25 CSI and TA at 70. All I would do now is lower ph to 7.6 when it gets to 8.0. This will slowly lower your TA which will slowly slow down your pH rise until TA and pH become fairly stable.
 

tstex

Silver Supporter
Aug 28, 2012
1,578
Houston, TX
Thanks p-dv...done.

Yes, from the orig documentation I read, TFP has lowered the overall TA's... I like the "lower the pH to 7.6 when it gets to 8...I usually lower pH to 7.5 when it gets to 7.8...rarely do I let it go to 8. Since my plaster is cured and I am no longer in the "keeping the acidity lower per installers", I'll let that pH get a bit higher before sending her down again to the mid 7's...I will then document the frequencies of adding MA and see if they become less and less over time, which I am projecting they should. Once the pH becomes erratic, I'll then do the NaHCO3 addition to raise TA again...

Again, appreciate your follow-up and good luck,
tstex