yet another CH question

[calstar]

Inground pool replastered last year 3/14, Santa Barbara city fill water hard, CH 400, last august it was 475+-, slacked off on CH testing over winter, probably let the ph get to high, now at 725+-.

current reading

TA 110
PH 7.5
CYA 35
FC 5-6
CH 725
CSi .3 (high end of the "ok" range)

Water is crystal clear, we're in a major drought here in SoCal, really don't want to dump half of 14,500 gal to get the CH down to the 570+- range, and refilling entirely would be nearly immoral given the drought conditions.

What are my best options to keep CH from climbing any more?

thanks, Brian

 

[JasonLion]

There aren't many options, and none of them are exactly simple, but here are some suggestions:

You can top off evaporation with water from a water softener, instead of regular tap water.

You can gather rain water and do water replacement without using tap water.

You can cover the pool with a solar cover most of the time to minimize evaporation.

It is possible to manage CH levels up to roughly 1,000 ppm, though it takes increasing amounts of attention as the CH level goes up.

 

[Richard320]

I use pool water on the lawn and refill it with what would have been used for irrigation. You do lose some CYA, but that gives room to use a floater with trichlor pucks when leaving town without fear of raising CYA too high.

Another note: if you're testing CH by hand, it may not be that high. My CH reading dropped 200 ppm when I switched to testing with a speedstir.

 

[Patrick_B]

The unfortunate truth is not much, but Jason pretty well covered your only options. CH only increases with evaporation and only goes down when you add a water source containing less. If it isn't a good deal less, it's difficult to outrun the increase. I suffer the same problem with as do many of us. My well gives me 700+ CH.

 

[calstar]

Another quick question. Does an elevated pH increase CH in the first year of a pool replaster? I ask this in relationship to the plaster curing over the first year and am wondering if for some reason the pH rise during the cure period has something to do with rising the CH.

I do have a solar cover(although not used 100% of the time) so evaporation has not been a big factor, that and the little rain we've had has not required adding city fill water to the pool. Going forward I'll keep the pool covered except when we're in it. I'll get a speedstir as well, fingers crossed.

thanks for the all the advice, it's much appreciated.

Brian

 

[duraleigh]

Does an elevated pH increase CH

No, but you never want your pH elevated (above 7.8) anyway and especially during the first year.

 

[JasonLion]

As plaster cures it raises PH, TA, and CH levels. The PH changes are fairly obvious, but the other two go up as well. This typically lasts about a year after the plaster is applied, quickly during the first month, and more slowly for roughly a year.

 

[calstar]

No, but you never want your pH elevated (above 7.8) anyway and especially during the first year.

OK, I'm curious, why is that?

thanks, Brian

 

[JasonLion]

High PH levels lead to calcium scaling and metal stains. There are other factors involved, so high PH doesn't guarantee trouble, but it makes it so much more likely that it is good to be in the habit of keeping the PH under control.