How much Calcium is too much?

[tim_pool_newbie]

I'm now in my 2nd summer of inground plaster pool ownership and just about as long as a firm BBB believer. For the most part I've been able to maintain a crystal clear pool all season so far with only about a 96oz bottle or two of chlorine a day. My chemical levels have been spot on against the recommended levels.

Last week I went away for the work week on business, and so threw in 4 pucks and then just had my better half add a 96oz bottle of bleach in every night. Seems to have worked just fine. CYA increased by about 10 - which I expected.

However, this week my Calcium level seems to have suddenly increased. What would be the main cause of such an increase? Rain??

My current levels are:
FC - 2
CC - 0
TC - 2
pH - 7.8
TA - 80
CH - 420 (has been in the 250-300 range all season)
CYA - 60
Temp - 82

Everything I read says more calcium is better than less, but the range seems to be no more than 350. So is going higher than this a problem?

I have a large group coming this weekend and I'm sure there will be splashout, and since I'm seeing the filter pressure increase I'll do a backwash on Friday probably, before the weekend party. Should I be looking to get some more water replaced prior to all this to bring the CH level down? Or is my 420 level not of concern?

 

[RobbieH]

Were your pucks Cal Hypo? That would be why, if so.

350 is the high end of the range, but you can maintain your pool at 420 with no problem. You just have to keep an eye on pH and TA and you won't have any problems.

 

[ROB N]

Our water has high Ca, our pool water has Ch above 500. it has not been a problem. like RobbieH said just be vigilant about keeping the Ph on the lower end of the scale to avoid calcium scaling.

 

[tim_pool_newbie]

No, I used four 3" Trichlor pucks. Since I travel often for work and nobody else at home wants to get that involved in water testing and adding chemicals, I've used this method before and never had the calcium increase this much. We have had a lot of rain though, so I was thinking it might be from that.

But my biggest concern is not HOW it got there, but whether it's OK to leave it there. Sounds like it's still at a manageable level for now.

 

[RobbieH]

You will be fine. I've never heard of calcium in rain, but I've heard of acid rain hurting calcium surfaces.

 

[Richard320]

My guess is that you didn't mix long enough. When I went from manual swirling to a speedstir, my CH miraculously dropped!

420 is no big deal anyway. I don't think I've ever been that low since I bought the house. If you'll be backwashing, it will go down again anyway. If it really is that high.

 

[duraleigh]

The calcium didn't come from the rain. I think Richard's idea is probably pretty logical.

What is the CH of your fill water? It's probably less than 420 so calcium will go down if you choose to drain some of your pool and refill but, as suggested, keeping your pH and TA down in the lower ranges of safe will ensure you don't have a problem

The above is not why I posted....

Your FC is too low and entering in to a pool party, I would suggest you get your FC up to around 7-9ppm to ward off the anticipated bather load. After the party, keep it 5-7ppm.

 

[JamesW]

Any time that someone gets an unexpectedly high calcium hardness reading, I suspect the possibility of test error. I see in your signature that you had a Nature 2 cartridge at one point.

Metal ions (usually copper) can cause errors in the calcium hardness test. If you add 5 to 10 drops of reagent R-0012 first, you can usually eliminate the interference. Count the initial drops of R-0012 in the total number of drops needed to change the color from red to blue.

Also, be aware that some trichlor tabs now contain copper. Check the label for copper in the trichlor. The tabs might contain blue specks if they have copper in them.

Black or green stains can indicate the presence of copper. However, if you have dark plaster, they might be hard to see.