Converting to salt with a very high CH

[thilbert]

Hi all! Good to see the forum active again. Welcome back Ben, you've been missed.

I am in the process of converting my pool to salt. My numbers are:
FC 5
CC .2
TC 5.2
Alk 75
pH 7.1 / 7.2
CH 520 <-
CYA 20
Borates 30

I am raising CYA to 70 and am aerating the lower Alk to 60ish.

When I started the opening process, I had loads of leaves and detritus but have managed to clean all that mess up and am now swimming in my crystal clear pool.

The problem I am having is that I've got scale - EVERYWHERE. It's attached to my liner and feels like sharkskin or light grit sandpaper. When you rub it, it comes off in clouds. I am assuming that since my CH is so high that it is calcium. I need to find a way to fix this as I don't want to have Salt Cell issues with calcium deposits.

What's the collective wisdom of eliminating Calcium without draining?

Am I just going to have to live with the pH in the low range to keep calcium from precipitating on the walls and salt cell?

Thanks all.

P.S. Ben it really is good to have you back. Will be donating soonest.

-Troy

[Watermom]

There really isn't another way to eliminate calcium without draining. (Not a total drain. Partial drain and refill.)

[chem geek]

Are you sure your numbers are accurate? If I calculate the saturation index using those numbers and a water temperature of 80ºF (and using 7.15 for pH) I get -0.27 which should not be scaling. Was the pH much higher when you opened the pool (or the other numbers)? If so, then that might explain the scaling.

The scale can be redissolved by having the pH kept low (but probably not below 7.0 for too long) along with some brushing and if that doesn't seem to work then there are calcium scale reducing products which are metal sequestrants that are focused on holding calcium and dissolving scale. Others on this forum might have some special tricks for dissolving scale.

[Watermom]

But, to clarify, chem geek --- dissolving scale will not reduce the calcium level in the water. Correct?

[thilbert]

Yep, numbers are correct. Yep, the pH was much higher when I started cleaning up, as was TA. I've been keeping the pH fairly low along with daily brushing, and while it seems to help, you really need to get in the pool and scrub with a light 3M pad - the blue one - to get the stuff to come off completely.

On a related side note, I went through a 1.5 gallons of 31% MA and had to buy more. The MA I had was a couple of years old. I had to buy new stuff and I noticed that it had a much more dramatic effect than the old. I looked over my log and realized that the pH was not changing as it should with the addition of the old MA (the pH change wasn't even close to the pool calc). I guess MA can go bad?!

Here's to hoping that using new MA will improve scaling matters.

Need a line on that calcium specific sequestrant if you have a brand name, please. I'd rather not get it from the pool store that shall not be named.

Oh, not to put too fine a point on it (and not that it changes the SI too dramatically) but here in DFW, my water temp is hovering around 88. Kids and wife love it, but I have to say I prefer a cooler pool, especially in August when it's 105 until the sun goes down.

Are you sure your numbers are accurate? If I calculate the saturation index using those numbers and a water temperature of 80ºF (and using 7.15 for pH) I get -0.27 which should not be scaling. Was the pH much higher when you opened the pool (or the other numbers)? If so, then that might explain the scaling.

The scale can be redissolved by having the pH kept low (but probably not below 7.0 for too long) along with some brushing and if that doesn't seem to work then there are calcium scale reducing products which are metal sequestrants that are focused on holding calcium and dissolving scale. Others on this forum might have some special tricks for dissolving scale.