TA getting too low

[setsailsoon]

folks,

So I've been delighted with my TFP and have been learning a lot since last Nov when I joined. We use our pool a lot even in winter since we're in S Florida- solar/gas heaters spoil us! All test results have been in range using my TF-100 except TA has slowly been creeping down from 130 to a new low of 50 yesterday. I've never adjusted this number but read up on it last night, got my 12lb bag of Baking Soda at WM and added about 1/3 of the amount required to get back to 100 (40 oz by vol). Seemed to dissolve well (pH and FC adjusted yesterday). I'm hoping this goes as well as the other adjustments based on the Pool Math Calculator... they're always spot on! So here's my question. The PM Calculator shows this baking soda addition will increase the pH a LOT (~.8) but I've read that careful addition in small amounts will reduce this. I'm ready to make large pH reduction if needed (in small increments of course) but is there anything else to do other than just monitor the pH and make acid addition as appropriate?

Any comments would be appreciated. This is my first time with TA adjustment and I'd like to be sure my plan makes sense to you experts.

My most recent test results are shown below. Please note I've used trichlor to chlorinate for the past 2 months to increase the CYA and it looks like I'm getting close to target so I'm now back to 10% bleach. I'd like to be on the low end so I can use tablets when needed later this summer for extended travel without getting too high on CYA.

Chris

Date	TA	CYA	FC	CC	CH	PH	Actions/Observations
14-Feb-16	60	50	6	0	275	7.7	Rain
15-Feb-16							Rain
16-Feb-16	60	50	6	0	275	7.6	Big Rain! Then Sunny later, removed remaining trichlor
17-Feb-16			5	0		7.7	Sunny!
18-Feb-16			3.5	0		7.8
19-Feb-16	50		3.5	0		7.8	readings left 7 am Added 12 oz Muratic, 16 oz bleach, 8pm 4.5 FC pH 7.5
20-Feb-16	50		4.5	0		7.6	Added 40 oz Baking Soda

 

[pooldv]

Trichlor is acidic and is probably helping to lower your TA. I wouldn't raise TA much above 60 or so and then wait to see how your PH acts. If PH remains stable then leave your TA wherever it lands between 60 and 80. What is the TA and PH of your fill water?

 

[duraleigh]

Baking soda typically has very little affect on pH. Recheck your calcs. If you get the same thing, post back and give us ALL your parameters that you have input.

 

[setsailsoon]

Baking soda typically has very little affect on pH. Recheck your calcs. If you get the same thing, post back and give us ALL your parameters that you have input.

Dave,

You're absolutely correct, I had the calculator set to Washing Soda instead of Baking Soda. The results I got were almost exactly as predicted.

As always, thanks so much for the help!

Chris

 

[Texas Splash]

Good one Chris. It's good to do that from time to time - just to keep Dave on his toes.