PH drifts down

[IronMan13]

hey all. i'm on my 3rd season of having a pool. been following the TFP method since the start. details of pool are in sig. for the most part things have been going well for me, have had some random incidents of water cloudiness pop up due to trying to strike the right balance of pump run time and SWG % but otherwise hadn't had a ton of issue. that being said one thing i've noticed is that my TA and PH have pretty much stayed the same for the entire 3 seasons. which i find weird since the general theme is that if you have a SWG the PH will creep up.

Every time i've measured TA its been between 110 and 130, which i chalk up to just variances in my drops when doing it. PH has also always pretty much been 7.2. I got one of those PH testers last year and whether i use that or the drops they measure the same.

I decided this past week to add some 20 Mule borax to raise the PH a bit as the kids always complain about eyes hurting. I put 1 box in (4 lbs) and confirmed it raised my PH to 7.6. fast forward a few days and i tested the water again today and my PH is back down to 7.2. i've never seen it go below that, it appears that it gets to 7.2 and just stays there. (full transparency my water is cloudy again and FC is down to 1, so it is fighting something right now). for this past week i've been running my pump from 8am to 10pm and have the SWG set to 100%.

only chemicals i've added is liquid chlorine and dry stabilizer as needed. we do have an auto cover and keep it closed overnight but generally open it during the day unless its raining then we keep it covered. pool was uncovered during the day through the weekend and monday but stayed covered yesterday as we were busy and didn't get a chance to open it.

Last full readings

FC - 1 (today)
PH - 7.2 (today)
TA - 110 (5 days ago)
CYA - 70 (5 days ago)
CH - haven't tested this year

any thoughts/suggestions on what i should do or could be doing wrong?

Thanks!

 

[mknauss]

"auto cover."
The cover being closed traps the CO2 in the water causing the pH to fall. SWCG has no discernible effect on pH.
Open the cover more to let the CO2 outgas. Point the return eyeballs to the surface to create as much disturbance as possible.

 

[duraleigh]

pH in a pool VERY rarely goes down, so I can't explain it. Your pH of 7.2 is within our suggested range........I would leave it.

If it goes down further (into the 6's), please post back........you may well be one of the LUCKY ones who don't have to use acid!

 

[IronMan13]

"auto cover."
The cover being closed traps the CO2 in the water causing the pH to fall. SWCG has no discernible effect on pH.
Open the cover more to let the CO2 outgas. Point the return eyeballs to the surface to create as much disturbance as possible.

thanks for the reply! would being covered overnight (roughly 12 hours) each day for 2 days plus 1 day of being covered for 24 hours be enough to drop the PH by .4? (7.6 from when i put the borax in to 7.2 today)

Timeline is essentially

Saturday - open all day with swimming, put borax in to raise to 7.6 covered at night
Sunday - open all day with swimming, covered at night
Monday - open all day, very little swimming, covered at night
Tuesday - covered all day and all night
Wednesday - open in the morning tested PH 7.2

 

[IronMan13]

pH in a pool VERY rarely goes down, so I can't explain it. Your pH of 7.2 is within our suggested range........I would leave it.

If it goes down further (into the 6's), please post back........you may well be one of the LUCKY ones who don't have to use acid!

thanks for the reply! So far the past 3 years its basically stayed at 7.2 and doesn't change. same with TA being around 120 avg. i know thats considered "high" for a SWG but is in line with the overall range. i don't want to have to constantly put acid in to keep it down but i'm also unsure if its ok that it always stays at 7.2 and never changes. makes me think something is wrong

 

[mknauss]

thanks for the reply! would being covered overnight (roughly 12 hours) each day for 2 days plus 1 day of being covered for 24 hours be enough to drop the PH by .4? (7.6 from when i put the borax in to 7.2 today)

It must be. The only way for pH to go down is for acid, acidic products, etc to be added to the water.
Try pointing the eyeballs on the returns such that the flow breaks the surface of the water. That may help release some CO2. The cover inhibits any wind from rippling the water surface. That means no 'aeration' and thus the CO2 does not release as rapidly.

 

[MITBeta]

the kids always complain about eyes hurting.

FC - 1 (today)

These two statements may be related. You don't have enough chlorine in your pool.

See the FC/CYA Levels.

 

[wireform]

The SWCG is designed to maintain a given FC but it won't work to get the pool out of the algae slump. Skip the OCLT and go for the slam asap although a bit much with a 70 CYA. You can do a "no drain water exchange" to bring the CYA down to a more manageable slam level and then bring it back up when the slam is done. It will use alot less chlorine for the same slam outcome.