CH keeps getting higher every year

[SWpisces]

Hi. I keep a running record on an excel sheet of all my test measurements. This is our 3rd summer for our pool and we started out with a CH reading of 140 ppm and got it to the correct goal of 300. Every year it has crept up and now after opening we are at 450 ppm! How is that when we have obviously had to replace water for evaporation, etc? We do tend to have hard water in our area (Albuquerque, NM). With our drought, I obviously don't want to have to drain any and replace. Should I be worried about any consequences with this high CH reading?
I got new test chemicals last summer....perhaps I need to get new again?
Everything else seems to be in good parameters. We use the Taylor Kit K-2006 (because I bought it before I found the tfp test kits.

 

[Isaac-1]

Have you tested how hard your fill water is? We have at least one member that also has very hard fill water that has rigged a rain catch system to divert CH free water to the pool, something you may want to consider as droughts tend to break eventually.

 

[SWpisces]

According to our Albuquerque water authority details it gives 7.3 hardness for our particular district. Not sure what that means?

Our TA is constantly high here, so I tend to keep the ph around 7.2 and let the splashing be the aeration to get the TA down to normal parameters.
Right now it is high again (140) as we haven't been swimming much yet. Could this be a problem too with the CH?

Today's readings:
FC 8.4 ( I had to shock a few days ago as I had a high CC)
CC .1
ph 7.8
TA 140
CH 450
CYA 75
Salt 3000
Temp 83*

 

[duraleigh]

Ch does not leave the pool through evaporation (CYA doesn't, either). Only through splashout and only then if your fill water is noticeably lower than the CH level in your pool.

Pools throughout AZ and NM have your same issue. Partial drains and refills are the answer but check your fill water CH first.

 

[Richard320]

According to our Albuquerque water authority details it gives 7.3 hardness for our particular district. Not sure what that means?

Our TA is constantly high here, so I tend to keep the ph around 7.2 and let the splashing be the aeration to get the TA down to normal parameters.
Right now it is high again (140) as we haven't been swimming much yet. Could this be a problem too with the CH?

Today's readings:
FC 8.4 ( I had to shock a few days ago as I had a high CC)
CC .1
ph 7.8
TA 140
CH 450
CYA 75
Salt 3000
Temp 83*

The problem is that the minerals in the water don;t evaporate, even though the water does. It's solar distillation. So CH keeps climbing. TA is in the fill water. If you plug your numbers in the pool calculator it will calculate the CSI. If you lower pH and TA a little on your targets you will see that CSI goes down. High CSI predicts scaling. Low CSI predicts plaster etching.

450 CH is still easily manageable. There's an article in Pool School on how to lower TA.

 

[chiefwej]

When water evaporates the calcium is left behind. You add water with more calcium, so it gradually increases the CH level in the pool. I start out with about 350 in my fill water and after a couple years (with desert temps and evaporation rates) end up with near 1,000 for a CH level.

High calcium levels can be managed with out scaling. It requires close monitoring of pH and TA levels to keep the CSI index at or near zero. For full explanation see Pool School.

 

[SWpisces]

Ahhh...THANK YOU everyone! Didn't know some of this...that's why I love this forum! so appreciate your brains!! I'll keep a close eye on the ph and TA....

If I continue to keep my ph at 7.2 and aerate with the splashing I should be good, correct?

 

[Richard320]

Ahhh...THANK YOU everyone! Didn't know some of this...that's why I love this forum! so appreciate your brains!! I'll keep a close eye on the ph and TA....

If I continue to keep my ph at 7.2 and aerate with the splashing I should be good, correct?

You only know if it's good by testing and plugging in the numbers.

From my own experience: when CH gets to about 900, you have very little wiggle room on TA and pH to keep CSI neutral. So you're good for a while.