Calcium Hardness increasing

[Blue114]

My latest results

PH 7.5
FC 3.5 (will adjust that to 6 with bleach )
TA 90
CH 480
CYA 90

The pool calculator is reading as balanced, but the calcium keeps increasing. I don't want to remove water as it's too expensive in Brisbane to keep refilling.

Is this high reading a concern and I have read about chemicals that reduce calcium. ie: Zodiac Calcium Down

Cheers

 

[Richard320]

480? Hah! Try 825. I've actually gone as high as 1100 before.

If you got that reading by hand-swirling, it's probably reading higher than reality. My CH dropped a couple hundred points when I went to using a speedstir. Also, when you get into that range, use the extended directions and 10ml water. Does it matter if it reads 475, 480, or 500? Not really. But it does save reagent, and a lot of time.

I keep the pH below 7.5 and the TA below 70 and that keeps my CSI negative, so it actually is slooooooooowly lifting scale, not just preventing it.

I have a hose fitting on my return pipe, which has made it really easy to use pool water on the lawn. And then I replenish with lower CH tap water. Same water used, it just gets run through the pool. I don't know how the salt will affect things, though, since I use jugs of bleach and you have a SWG.

I have zero firsthand experience with Calcium sequestrants. You might try searching that term here and see what comes up.

 

[257WbyMag]

Yes, Richard320 is proof-positive that one can manage to keep the water balanced despite having an extraordinarily high calcium hardness. By managing your CSI correctly, you can remain scale free. Take a look at pool-school/calcium_scaling for more information on this.

Have you checked to see what the source of your rising calcium might be? If you are using calcium hypochlorite, you should stop since that raises your CH every time that you use it. How about your fill water? Have you checked to see what the CH is on your fill water? It might surprise you as to how high it is.

 

[Blue114]

Thanks. I won't panic just yet. I'm not using Calcium Hypochlorate. I have no idea why it is rising. We have had a lot of storms lately that added about 4 or 5 inches to the pool. It's still looking pretty good so I'll keep it balanced and see what the coming months hold
Cheers

 

[257WbyMag]

Well, if the water that you use to fill and top off the pool has a high calcium hardness, then that is probably where it is coming from.