Water cascades and raises pH?

[HardTrance9]

Hi,

i have noticed that on two pools (SG and JK on signature) the pH levels are hard to maintain at 7.5. They usually go up to 8.2 on every "service" we make on them.

We get there, we check pH, we adjust with muriatic acid to 7.5 and then come back in three days again just to find that the pH is again at 8.2.

The pumps on both are running for 8 hours everyday and the water from the spa cascades down to the pool. I believe this kind of "aeration" raises the pH ??

Do you think this could cause the pH to raise? Do you recommend anything to prevent this from happening? Sometimes the pools are not being used but the maintenance is required.

Both pools have automatic fill systems but they don't loose water so that new water comes in that often (raising the pH as the city water here is high on pH).

:?:

 

[no-mas]

Both SWGs and the aeration caused by the falls will cause the pH to rise. Can you post a full set of test results? If your TA is elevated, it will also cause the pH to increase, and lowering the TA may help slow the rate of pH rise. Just guessing without test results, though.

In my pool, with 3 sheer descents and a SWG, I keep my TA at 60. Many of the experts on this forum have suggested that TA of 60-70 will help decrease the rate at which pH increases. It certainly worked in my pool.

 

[Guest]

8.2 is very high! I would try and address it sooner so that it does not reach that level, if at all possible. You may need to get to it a little more often, but you will cause damage if you allow it to stay that high (and it may be higher since most test kits only go to 8.2).

 

[HardTrance9]

Here are the tests from January 14th, 2010:

EDIT on JK pool results..

JK Pool
-------
Jan 14th, 2010
fc 3
cc 0
ph 8.2
ta 190
ch 160
cya 50
temp 18
salt 4150

SG Pool
-------
Jan 14th, 2010
fc 2
cc 0
ph 8
ta 170
ch 230
cya 55
temp 23
salt 1230

Working on lowering the TA but here are no good options to do so...

 

[JasonLion]

If you adjust the PH to between 7.0 and 7.2 each week, instead of 7.5, the TA will come down more quickly. Lower TA levels will mean slower increases in PH. Also, adding borates to the water can help to slow down the rate of PH increase significantly.

As things stand, they are either getting, or very close to getting, calcium scaling, especially in the SG pool (where the lower salt level and higher temperature have brought the CSI up to around 0.9).

 

[HardTrance9]

Thanks for the hint Jason... Will follow your suggestion, sounds like it will help for what we need... Will get back to you guys once there is any progress on this..