Hello, I'm a newbie here, just wanted to share what a newbie just went thru for over 3 weeks, Bought a new spa about a month ago, followed instructions to the tee on set up and chemicals. The next morning my PH was off the charts, All other tests were within range, except alkalinity, it was about 70. I added PH down (sodium bisulfate 93.2%) to the suction, filter basket like it said to do and turn on high for about 15 min then retest in 30 min. To make a long story short I added over 20 oz. to finally see my PH come down to 7.8. Seemed like a lot, I was beginning to think to myself I made a bad purchase, If I have to do this all the time. The next morning was the same thing, my PH was off the charts again, and no one used it, I did have the filter cycle go on for about 1.5 hours during the night. This has been going on for about 3 weeks now, along with my alkalinity jumping all over the place also. Well, I found the answer to my problem, I read somewhere online or in a forum or just a page somewhere that you should not use the bubbler while mixing chemicals, it said it will raise PH by adding Oxygen or carbon dioxide, I can't remember ( A chain Reaction thing). (Air to the Jets) during the filter cycles and while adding chemicals to the spa, So I now turn on high without air being injected to the spa. The testing has been right on now for over 3 days now. Good Grief ! ! Just wanted to share a what a newbie like me went thru. I never owned a spa in my life, I guess at over age 60 I still can learn. My heart rate finally went to normal as well.
Chasing PH for over 3 weeks,Daily
- Thread starter Val B
- Start date
- Jan 21, 2014
- 1,069
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Yep, aeration increases pH. Just be aware of that when your using the spa and you'll know what to expect.
Some people will add borates to the spa once you get the TA in range which will help calm down the PH rise from the bubblers and jets. I have never tried it yet but may this year once I just have my attached spa open with the main pool winterized. There are other forum articles explaining how to do it if interested.
Also, the amount of pH rise depends on the type of disinfection chemicals you use and that depends on your bather load. Those using Nature2 with MPS don't need as low a TA to be stable since MPS is quite acidic. Those using Dichlor-only can use a somewhat lower TA but not very low since Dichlor is also net acidic when accounting for chlorine usage/consumption. Those using the Dichlor-then-bleach method should get their TA down fairly low to around 50 ppm and then use 50 ppm Borates for greater pH stability. And yes, aeration raises the pH, but only when the TA is too high or the pH low. This chart will give you some idea of how over-carbonated the water is compared to the carbon dioxide in air at various pH and TA levels.
So welcome to TFP and thank you for sharing what confirms what we teach here and that the pool and spa industry unfortunately don't tell consumers. Pool and spa water is intentionally over-carbonated so increased aeration will have the pH rise unless chemical additions are lowering the pH. Most importantly, TA is not just a measure of pH buffering but is a SOURCE of rising pH on its own.
So welcome to TFP and thank you for sharing what confirms what we teach here and that the pool and spa industry unfortunately don't tell consumers. Pool and spa water is intentionally over-carbonated so increased aeration will have the pH rise unless chemical additions are lowering the pH. Most importantly, TA is not just a measure of pH buffering but is a SOURCE of rising pH on its own.
Just a quick question for Chem geek which I should have referenced concerning this (I know I read all of your stuff the past year..awsome!) I had bought the Duda boric acid granules last year which I'm going to use this year in the spa 900 gallons to bring up the borates to 50ppm. I'm going to go with the liquid chlorine method which my CYA should be 45ppm when I close my pool. Can I use the Leslie's non chlorine shock MPS once in a while to clean up the spa after a soak without any adverse side effects? Thanks!
You can use MPS as an oxidizer for some of the bather waste, but without silver ions in the water (say, from Nature2) the MPS is not a disinfectant so you'd want to use at least some chlorine for that purpose. MPS is also more expensive than chlorine and there shouldn't be any need for using it. Bleach (or chlorinating liquid) should work well just as it does in your pool. You should add it after every soak in proportion to how long you soak -- add enough so you have a measurable residual the next time you soak. I presume you are doing only a little mixing of the spa and pool water. If you do enough, then you shouldn't need to add much if anything, but that won't be very efficient for maintaining temperature.