Solving high pH without the 10 day pool store treatment

Jump to latest Follow Reply
D

dha5447

Member
May 8, 2020
10
Nebraska
Hey everyone-- I know there are a ton of great articles and tools here. I've ready many of them, I'm mostly posting this as a sanity check to make sure I'm headed in the right direction.

I have an 8000 gallon saltwater pool. I bought a tester for the salt and it shows 3200 ppm (tester calibrated with known 3000 ppm water). For some reason the pool store test showed 2800 ppm and they said it should be around 3500-4000.

Anyway, I'm still figuring out how best to keep free chlorine levels where they need to be with SWG. Chlorine seemed to just disappear with no CYA in the pool. I've added about 2 lbs of stabilizer/CYA using the skimmer sock method. I've also added 2 lbs of dichlor for two shock treatments, so that should raise CYA some. I don't have a great way to test CYA at this time, but I did receive some test trips that might help.

In the meantime, though my pH is pretty high-- 8.2 according to the water test, and TA is 250. The pool store recommends a 10 day treatment of their "lo 'n slo" (active ingredient Sodum Bisulfate) to reduce pH and alkalinity. My understanding is that I can better solve this with acid. So I picked up some muriatic acid and I'm looking to add it today. Maybe with some aeration I can get the alkalinity down too.

Thanks for any thoughts you have.
 
Initial thoughts
1) You need a proper test kit to keep tabs on pH and TA while you're lowering TA.
2) You need a proper test kit to measure CYA.
3) You need a proper test kit to measure FC accurately.

Further thoughts

Lowering TA can't be done on a schedule. As the TA lowers, the amount of acid needed to shift pH goes down. And the speed of the pH rise depends a lot of the amount of aeration -- anything from fountains to swimmers --- and on the amount of TA remaining. It needs to be done as test then dose, not just dose dose dose. You'll end up driving pH too low and may damage plaster or heater and irritate swimmers' eyes.

Smart move to buy the Muriatic Acid. Low-n-slow leaves sulfites behind which ar enot good for SWGs.

If you maintain proper FC/CYA levels you will never ever need to do a "shock treatment."
 
I had a test kit on order already, but it does not include CYA test. So unfortunately I don't know it. I think I need another test kit. Based on what I've added, I think CYA is in the 50-70 range.

pH is now down to around 7.6. I haven't tested TA yet. FC is looking more consistent now with keeping the SWG clean (deposits build up after just a few days) and running it at night.

My main problem now is with the sand filter pump-- it generally needs backwashed at least once per day, which seems really excessive. It's been windy with debris blowing in from a nearby tree. I generally sweep fine debris up from the bottom so the filter catches it, but then within a few hours my pressure is up high and nothing is coming out of the pump. Water has stayed nice and clear. Could I have an algae problem I don't know about yet?
 
dha5447 said:
I had a test kit on order already, but it does not include CYA test. So unfortunately I don't know it. I think I need another test kit. Based on what I've added, I think CYA is in the 50-70 range.

pH is now down to around 7.6. I haven't tested TA yet. FC is looking more consistent now with keeping the SWG clean (deposits build up after just a few days) and running it at night.

My main problem now is with the sand filter pump-- it generally needs backwashed at least once per day, which seems really excessive. It's been windy with debris blowing in from a nearby tree. I generally sweep fine debris up from the bottom so the filter catches it, but then within a few hours my pressure is up high and nothing is coming out of the pump. Water has stayed nice and clear. Could I have an algae problem I don't know about yet?
Click to expand...
You might. A filter ought to be able to go at least a couple weeks.

The way to check that is Overnight Chlorine Loss Test
 
Thanks for the replies, everyone. The pool has been anything but trouble-free so far, but I'm hoping to get there. I am using this testing kit: Amazon.com : Poolmaster Essential Collection Chemistry Case (22260) 5-Way Swimming Pool & Spa Water Test Kit, Small, Neutral : Swimming Pool Liquid Test Kits : Garden & Outdoor . I recognize that I need better testing, and I have CYA, chlorine, and pH test kits on the way from TFTestKits.net. Maybe not much I can do until they come.

Three big frustrations right now:

1. Lots of debris on the bottom. There is a tree right next to the pool, and it's been very windy for the past week which doesn't help. I have an Intex Auto Cleaner which should help a lot, but it hits a pool edge and won't reverse like it's supposed to. Intex is sending a new gear box, and I hope it works. As it is, I spend 30-60 minutes per day trying to keep it clean.

2. I have to backwash usually once a day, as the pump output goes down to almost nothing that quickly. I called Intex, and they were stumped, except they said to check the sand. I checked to make sure I had #20 silica sand, and I do. Today I've been filtering and sweeping debris, and I'm about to do my 4th backwash in 24 hours.

3. The SWG gets white deposits extremely quickly. I got it completely cleaned off yesterday, and in less than 24 hours most of the plates are coated again. There are also white flakes all over the pool, which I'm guessing is from this.

My understanding is that the white deposits might be related to high pH. It started at around 8.2. I've been using muriatic acid to bring pH down to around 7.6, then aerating and adding more acid when pH gets around 8.0. Maybe I need to be adding more acid at one time to bring the pH lower to help prevent deposits. Calcium Hardness was tested at 330.
 
You are still missing one test, calcium hardness. Calcium, pH, total alkalinity, water temp, salt, and a mathematical formula are used to determine your CSI, calcium scaling index. With the flakes that you describe, there's a good chance your CSI is high.

Scaling is caused not just by TA, but by a complex interaction of alkalinity, pH, calcium, salt, and temperature. One you have a good test kit in hand and the ability to test those numbers yourself, you can plug the numbers into an app and it will calculate your CSI. Only then will you be able to decide how to address the issue.

Don't add any more stabilizer to your pool until you can test the CYA. If there's any remaining undissolved, take it out. The only way to remove CYA is water replacement (or high temps and a lot of time, months/years), so it's much better to be low for a week while waiting for your kit, than to go too high and need to replace most of your water.

Hang in there, it does get better. I'm clearing a swamp - while it's certainly not trouble-free yet, it's much better than it was a couple of weeks ago.
 
  • Like
Reactions: mguzzy
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