Do I care that my CH is high? What problems will it cause?

[Bart]

Quick background:

Salt water pool, gunnite finish. I had a major calicum scaling problem when the pool was opened this spring (2nd year of use). I did two no-drain acid washes which pretty much took care of the problems. I've been testing my water and I know I have a couple problems that I'm dealing with and one problem (calcium hardness) that I'm not dealing with (don't want to replace 15,000 gallons of water).

My question is, what are my problems/risks/issues with keeping the calcium hardness higher than normal until evaporation/spashing causes enough water loss and replacement to bring things back to normal?

My latest pool store test results are below, but I'm a little suspect of some of the numbers (I got a higher CYA number (and so did they) a couple weeks ago before I added more CYA!) (Original CYA number was 55, but after adding 10 lbs of CYA it's down to 45!?!?!?) Doesn't make sense. Also the CH number was around 640 two weeks ago and now it's 375. Doesn't make sense!

Anyhow, here are todays numbers from the pool store (I tested too, but forgot my numbers at home

FC 1.0
CC 1.0
pH 7.4
T/A 145 (it was about 185, but I've been bringing it down)
CH 375 (two weeks ago it was 640)
CYA 40 (two weeks ago it was 55. I've since added 10 lbs CYA)
Total Disolved Solids 4500

The remedy for the high total hardness (CH) was to add 3 quarts of Scale Inhibitor accounding to the print out from the pool store.

Two questions:

1) Should I bother with the Scale Inhibitor or is that snake oil?
2) Can I just wait out the high hardess levels without doing major damage to people/equipment/pool?

Actually, a third question: Should I be concernend about my high total disolved solids number? I don't recall people testing for that or talking about it.

Thanks!!

 

[JohnT]

Re: Do I care that my CH is high? What problems will it cau

Calcium doesn't leave the pool when water evaporates. I'd be very suspicious of your readings. Since you've already had scaling, you need to be careful to avoid it again. What is the CH of your tap water?

 

[JasonLion]

Re: Do I care that my CH is high? What problems will it cau

If your CH level is 375, then you are just fine as far as calcium goes. If CH and TA and PH are all high then you can get calcium scaling. Your CH and TA levels are both just slightly high (now that you brought them down) and PH is just slightly low, so that should be fine. Scale inhibitor would help if CH was higher.

I hope your CC level isn't actually 1. Perhaps you meant TC? If CC is actually 1 you need to shock the pool.

Just ignore TDS. TDS is a total, which is unimportant. What matters is what the individual levels are.

It is clear that your pool store testing is not reliable. You would have a much simpler time if you had your own top quality test kit.

 

[Bama Rambler]

Re: Do I care that my CH is high? What problems will it cau

1. The scale inhibitor is most likely a sequetrant and it can help a little in certain circumstances.
If your CH is really 375 it's pretty manageable without any scale inhibitor.
Keep your pH on the low end and get your TA down to about 70 and you should be fine

2. You can wait it out unless your fill water is also hard, in which case it's going to constantly get worse. Keep in mind that CH doesn't evaporate so you can't count on that as helping. Splashout and backwashing is about all you have going for you.

3. About 3500 ppm or so of that TDS number is your salt so I wouldn't worry about it.

 

[Bart]

Re: Do I care that my CH is high? What problems will it cau

What is the CH of your tap water?

Don't know the answer to that one. We're on well water in Northern VA/Blue Ridge Mts. if that helps. Another data point is that last year was the first year of use of the pool and it was filled via tanker trucks. I found some test results that I posted last August and my CH was 250.

Since then, I've only added maybe a foot or two of water (not sure how many gallons that is, but it has to be a pretty small percentage of the total amount)

 

[Bart]

Re: Do I care that my CH is high? What problems will it cau

I hope your CC level isn't actually 1. Perhaps you meant TC? If CC is actually 1 you need to shock the pool.

It is clear that your pool store testing is not reliable. You would have a much simpler time if you had your own top quality test kit.

Yep! Sorry about that typo. My TC is 1.

I do own the TF100 kit and will be rechecking my results tomorrow. I just added some CYA last weekend (after testing) and my results were 55. I pulled a sample last night and was hoping to see it climb a little after 5 days in the water, but you're right, the pool store is not reliable.

 

[Bart]

Re: Do I care that my CH is high? What problems will it cau

2. You can wait it out unless your fill water is also hard, in which case it's going to constantly get worse. Keep in mind that CH doesn't evaporate so you can't count on that as helping. Splashout and backwashing is about all you have going for you.

.

Thanks Bama.

That's what I meant to imply.....it would come down as I added more water, not as the current water evaporated.

Need to be more clear!!