Calcium Hardness

[waterbear]

95" is less than what parts of Arizona and Texas experiences over the year so it really depends on where you live. Check out this Link for where you live to get an estimate.

WOW according to this my pool will lose it's full volume plus about 1 third more over a years time and my hot tub over 3 times it's volume!

[ndillon2]

You are correct. My strips test Total HArdness (1000+), while the pool store tested Calcium Hardness (460). Thank you for pointing that out. At least I feel A bit better about the results being so different.

[salinda]

WOW according to this my pool will lose it's full volume plus about 1 third more over a years time and my hot tub over 3 times it's volume!

Hey Waterbear...I live in Northern California and evaporation is always a problem. I am wondering if you use a cover at all. I use those silly solar fish and they do seem to mitigate the evaporation quite a bit.

Jumping in here, my calcium is also high at 520-530. It is actually hard for me to get it to blue with the kit because the water in the tube starts globbing up as I add more reagent. I recently successfully lowered my alk from 130 to 90. My ph is hanging out in the mid 7's right now for much longer than it ever has. I have had high calcium for years now and my plaster is very smooth. I do get flakes from the returns sometimes, but the cleaner sucks those into the filter, except in the spa where I use the PoolBuster to remove them. It actually seems like there are fewer flakes this year than in previous years...

I am keeping an eye on everyone's borate experiences as well, but things look good now so I don't want to mess with the water chemistry too much.

[chem geek]

Salinda,

When you had CH of 525, TA of 130, and the pH was rising and hit 7.7, then your saturation index was around +0.6 so slight scaling was possible. With your current TA of 90 and a pH of 7.5, your saturation index is a much more manageable +0.21.

If you use a non-acidic source of chlorine such as chlorinating liquid or bleach, you can lower your TA even more if you want to, even to 50 ppm, and this should further reduce the tendency of your pool's pH to rise. You'll probably find that something like 70 ppm will be fine.

Think of this as an advantage to having a higher CH pool -- you can have a correspondingly lower TA and have calcium carbonate saturation in balance and be even better off in terms of having less pH rise.

Richard

[salinda]

Richard,

Thank you so much! It was your previous comments on the feasibility of low TA with high CH water that gave me the courage to try to fool with the chemistry. I'm glad I did! I test my water myself, but so does the pool store when I go for a visit. This is a local store that maintains pools on their service with liquid chlorine. They completely concurred and understood Ben's method for lowering TA. It sounds like they use this method too. I am steering friends who are looking for a good pool store to this one from now on! The owner was a little concerned about the TDS of the water, but the CH has changed so little in the 3 years I have owned the pool that I am not really concerned.

I use an swg for chlorine. Are you proposing that I turn that off and switch to bleach? I could probably repeat the lower ph/aerating method and get the TA down even further. If I do the adjustment for stabilizer that others do, I am already there.

Maybe we should move this to a new thread....

[chem geek]

Sorry I didn't see your signature line and notice that you had an SWG. No, you don't need to move away from your SWG -- it's fine. But you can lower your TA a little more to around 70 ppm if you want to. It will lower the pH rise a little bit more. Up to you -- if the pH rise isn't annoying where your pool is at now, then there's no need to change it.

Richard