pH low and TA low

[tstex]

Morning to All,

I've been monitoring my pool now and the last set of tests I did [w TF-100] yielded a high pH 7.8+. This was over the Saturday. Did another FC and it's a 7, which is great...I seem to have the CL balanced well and changed from Pucks to Liq-CL [my CYA was 62ish] bc my CYA was slightly out of the ideal 30-50 range.

I again tested my pH last night and it was on the high end of the test of 7.8 and perhaps leaving it to 7.9 or more, so I bought and added some Muriatic acid 29%. I may have added a bit too much bc I am now below 7.2, but not in the 6.8+ range per the color-coded kit. My TA is 70-75 [I had to add one more drop but was so close to being totally clear, so it was not an 8 but more than a 7]. I know ideal is 100-120 [some ranges are 80-150]

my question is w the rain coming again this weekend, is it ok t leave the pH & TA at these levels or do you recommend adding some NaHCO3 to raise the pH. Our watered is aerated when leaving spa over spillover into pool and I have the 2 scuppers on that really aerates the pool...I know aeration/evaporation will help to reduce pH w out impacting the TA, but does so slowly...also the pump time on the scuppers is not free

Thank you and pls let me know if you have any questions.

Regards,
tstex

 

[JVTrain]

Not sure where you are getting the recommended levels for TA, but see ours here: Pool School - Recommended Levels

TA is usually better in the 70-90 range in a manually chlorinated pool but with a plaster pool, you also need to consider that in relationship to your overall CSI level. You'll find less pH rise with a lower TA.

Your pH is fine, the coming rain will actually drive it upward a little bit if the pool is uncovered. Rain = lots of aeration = pH rise (depending on TA).

 

[Texas Splash]

Joel nailed my comments as well before I could post.

tstex, I'd leave the pH alone for now. Your spa and spillover will help to raise the pH on its own shortly. Being just below 7.2 for a short period won't hurt you. But something else you might want to consider .... While the Pool School - Recommended Levels page gives us basic guidance to follow, every pool is different. You'll see the recommended TA for your pool is 70-90+. So it's okay to let is stay around 70-80. Some may even go down to 60 if it helps keep the pH down and more stable. Also, when you are on the Poolmath calculator, take a moment (after loading all of your test results) to review the CSI row to ensure you are protecting your plaster. The pH, TA, and CH work together for proper CSI. As for CYA, 30-50 is ideal this time of year, but in the summer when the TX heat is bearing down on us, going slightly higher may be required to save FC loss. You'll know next summer when FC is disappearing too fast and there is no algae. Hope this helps.

 

[tstex]

Joel/Pat,

Is CSI Ca Saturation Index? Just a guess...

Thanks for the link to the Pool School Chart. So it looks like I am all in the good ranges for now. My CYA [was using pucks but stopped 2 wks ago] is 62ish, so my FC should be 7 at that level and it is 7 right now. My TA at 70-75 is right there in the low acceptable range...my VSP runs from 8am-4pm so I'll get plenty of aeration. My CH was just out of the high range, but I was told for a still plaster/p-sheen curing pool, it was going to be there...

Thanks again and I'll print out my ideal ranges and put them inside my TF-100 kit...great forum !!

Also Pat, did you get hammered w rain last week? The poor San Marcos/New Bran. area got it again...we need the rains and it really helps to recharge the aquifers...just wished it would come in lesser amts but w greater intervals.

 

[JVTrain]

Yes. CSI is Calcium Saturation Index.

You NEED to input all your values into Pool Math http://www.troublefreepool.com/calc.html to see what your CSI is actually at. This will allow you to know what pH levels your should maintain to preserve your plaster.

 

[tstex]

Thanks - I'm going to re-test my CYA & CH then post back

Ok, Here are my readings for all of the following that I just did:

FC= 7 [done at 6am today]
TA = 75 [6am too]
CH - 350-400 [just did]
pH = 7.2 [just did]
CYA = 52-55 range - [just did] - as mentioned in the TF-100 kit, this is pretty subjective, but I keep putting drops in until I can move the tube left to rt at waist level and can no longer distinguish the dot there

Do these look okay?

 

[Texas Splash]

Yes, lots of rain with apparently more to follow. No worries. TFP will keep us in good shape.

 

[JVTrain]

At your pH of 7.2 the CSI is a little low, -0.43, but nothing to be alarmed about. If you maintain your pH in the 7.4 to 7.8 range, your CSI will be fine. Don't seek to lower your pH until you get a reading ABOVE 7.8. This will lessen your need to add acid and you'll likely find the pH is fairly stable around 7.6 and will take some time to rise above 7.8.

 

[tstex]

Thanks Train - this was the first time I added muriatic acid and I believe I over did it a bit...the pH prior was in the 7.8-8.0 range...I will tone it back and keep it more in the 7.4 range.

The Gunite/P-Sheen rep said to try to keep the pH 7.3.7.4 range more than the 7.6-7.8 range after the no-drain acid wash until it had cured for 12 mo's, which is late Jan-early Feb 2016. As w anything, the large swings from 7.8+ to 7.2-7.4 should be avoided as w anything lg delta, unless it's a SLAM. I will test every other day and make smaller adjustments to keep more stable...I appreciate your feedback -

PS - Send us a cold front..we are in the 80's in Nov and w 90-99% humidity, it's gummy...Land of 10,000 Lakes, must be nice !!

 

[JVTrain]

Haha. We're actually "warm" here for this time of year right now. High temps the last three days have been in the mid-60s which is fairly rare for early November. In about a month or two, I'll be BEGGING to send you some of our cold front. But, at least we can start skating on outdoor rinks and playing some pick up hockey!