Concern about CH and PH

Jump to latest Follow Reply
S

Slm3rob

0
Bronze Supporter
Mar 16, 2016
109
Conroe, TX
Need a little advice on CH and PH.

Pool is 9 months with water. PH rises quickly to over 8.2 every 3-4 days. I'll add enough acid to get it to about 7.5. I'll have to add in another 3 days again usually. If it rains, sooner.

CH was pretty stable over the winter at 350-375. Tested it 4 times today with reagents from last fall and new ones... got anywhere from 400-550. I know that is high. Tap water is 100 and pool has auto refill. Have had a lot of rain the last week. Do I need to be concerned and if so any idea why the rise or could the reagents be off? They are TF -100.

There has been a film on the pool tiles along the waters edge twice in the past 6 weeks along the side of the pool that doesn't get as much sun. The first time I thought it was pollen... we have had a lot this spring. It brushed right off but it happened again (15 year old daughter is bruising daily but she may have been missing the tiles).

TC is steady. Hasn't changed more than .5 in a month. Pool is salt. Pump run 9 hours, salt cell on for 8 hours at 80%. Pool is crystal clear. Here's today's numbers.

FC 7.5
CC .5
TA 60
CH 400-550 ???
CYA 80
PH 7.8
 
7.COLOR_Cleese_as_Frenchman.jpg

I laugh at your puny CH numbers!​



Your pool is easily managed with the high CH. My pool has only been below 500 CH once in the last five years for a few weeks, after a lot of rain. Plug your numbers into poolmath and then look at CSI. Is it +/- 0.3? No problem. Just keep doing what you've been doing. Your TA is coming down a little each time you add acid, so the pH rise should be slowing down some.

If you suspect Mustard Algae, take the pool up to Mustard Shock level with bleach and brush the suspect areas vigorously. I might be tempted to settle for jacking the FC up with the SWG to get through the weekend and then deal with it when there's less usage.
 
Plaster pools typically have rising pH for quite a while, some as long as 18 months before the pH settles down. My pool, now 4+ years old, has rising pH all the time, not as bad as it used to be but it still rises. I have to add acid every 7-10 days to keep the pH in range where I like it. So there's nothing too different with your pool.

For CH, the test can be a little tricky. First off, are you using a SpeedStir? If not, you should really consider getting one because it makes testing a lot easier and it makes tests like the CH much easier to perform. Also, are you adding R-0012 drops until the solution STOPS changing blue color? Many people make the mistake of ending the test at the first sign of purple to blue transition and that is incorrect. The titration ends when the blue color stops getting "more blue". That error also causes serious variations in test results.

Oh, and by the way, my CH is 1100ppm and I can keep my water perfectly balanced and with no scale...it's bit harder than when my CH was 600ppm, but it is doable. So you're not even close to being in danger with your CH.
 
My pool also likes 8.0 pH with the IC-40 SWG. Those things seem to really aerate or something. I'm working on TA reduction at the moment, but yours looks good already. Interested to hear ideas others might have. For now I'm ok using a gallon of MA every 2-3 weeks, but I may explore borates down the road. I have noticed that if I try to bring it down to 7.4, it hits 8.0 at the same time as if I had just dropped it to 7.6. So for now I just add enough to drop it to 7.6 to save MA.

Edit: Ah, nevermind, just noticed plaster. That's probably where your pH rise is coming from. Hopefully mine is just TA.
 
All good advice above... as is tradition... I would point out, that with a fill water CH of 100, you can set the CH of your pool where ever you like by draining the appropriate percentage of pool water and refilling from tap.
 
Richard320 said:

I laugh at your puny CH numbers!​



Your pool is easily managed with the high CH. My pool has only been below 500 CH once in the last five years for a few weeks, after a lot of rain. Plug your numbers into poolmath and then look at CSI. Is it +/- 0.3? No problem. Just keep doing what you've been doing. Your TA is coming down a little each time you add acid, so the pH rise should be slowing down some.

If you suspect Mustard Algae, take the pool up to Mustard Shock level with bleach and brush the suspect areas vigorously. I might be tempted to settle for jacking the FC up with the SWG to get through the weekend and then deal with it when there's less usage.
Click to expand...


Thanks. I hadn't thought of Mustard Algae, I'll read up a little bit more on that. I do think I should clean my filter, even though the pressure is good, we had a lot of pollen. It's slightly a more yellowish than greenish color.

Pool math says the csi is -0.04 If I lower the PH to 7.5 it would be -0.33. How do I correct it if I can't get the csi in range consistently? And if you know, why would the CH rise? Is it coming from the plaster?

I have lowered the TA purposefully. It had risen to about 80-90 over the course of a few months. I will up the salt run time to get more chlorine in the pool. It's weird. I had to turn the SWG off for quite a bit this winter and It was only running it at 20% when it was on. It's wasn't cold here except for about 3 days in December but it kept rising. Not as much sun on the pool I guess.
 
Slm3rob said:
A higher PH or lower? It's at 7.8 now. Pool math says taking it to 7.5 will get it to -.33

so lower?
Click to expand...
Don't balance to the CSI. You've got lots of room to move around still. Things only get ugly above 800 CH. Play around some more and see what happens when the water warms up.

7.8 pH is swimmable so there's no need to mess with it and a whole lot of SWG users find that running at the high end of allowable pH makes the water really stable so they go weeks without acid.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Slm3rob said:
Thanks. I hadn't thought of Mustard Algae, I'll read up a little bit more on that. I do think I should clean my filter, even though the pressure is good, we had a lot of pollen. It's slightly a more yellowish than greenish color.

Pool math says the csi is -0.04 If I lower the PH to 7.5 it would be -0.33. How do I correct it if I can't get the csi in range consistently? And if you know, why would the CH rise? Is it coming from the plaster?

I have lowered the TA purposefully. It had risen to about 80-90 over the course of a few months. I will up the salt run time to get more chlorine in the pool. It's weird. I had to turn the SWG off for quite a bit this winter and It was only running it at 20% when it was on. It's wasn't cold here except for about 3 days in December but it kept rising. Not as much sun on the pool I guess.
Click to expand...


Yep, it's mustard algae. Took me this long to figure it out. The waters been clear and the FC has been steady though I did up the SWG for the past week and a half or so thinking just a lot of sun in the pool.

Should i I turn off the SWG while I slam it ?
 
Yes, turn off the SWCG to SLAM. The FC level needed to SLAM cannot be managed by the SWCG. Be sure to get your FC to 40% of your CYA and then maintain it there until you pass the three criteria for a successful SLAM.

Take care.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply