Calcium went down

[datadr93]

Regularly test water but perform deeper testing monthly.

Last couple months, my calcium was 250. This month, my calcium was 180. Salt, borates, CYA maintained same values so splash out wouldn't make sense. I retested and same values of 180.

I top off pool with well water (use a H&G iron/softener pre filter on hose since we do have small trace amounts of iron and minerals). House is on full softener system but we pump in from a yard hydrant that does not go thru softener (much higher water pressure).

What would cause calcium to drop like that? I know many on TFP say with fiberglass pool and electric heat pump I don't need to concern with calcium levels. Does bring my CSI out of whack as well (-6.9).

Do I raise my calcium? No issues with water clarity.

Solar cover at night (temps drop down to mid 50s during nights)... Pool temp currently 87
TA 80
pH 7.4 (will aerate with deck jets today)
FC 7
CC 0
CYA 80
Borates 50

 

[duraleigh]

I don't see test results for the CH of the fill water. That may account for it. In any event, don't add calcium.

 

[datadr93]

I don't see test results for the CH of the fill water. That may account for it. In any event, don't add calcium.

You want CH results of the fill water? Just ran test and it's 200.

Keeping in mind when I top off pool, I'm adding maybe inch or two level every 1-2 weeks. Fills at about 3 GPM and I run for about 45 to 60 minutes.

No calcium add... got it. Just baffling that the level dropped that much in one month. Did battle mud pool due to topsoil runoff (was all laid same day a heavy rain hit in evening) and was only treated with constant filtering and 1 gallon 10% chlorine.

 

[duraleigh]

I thought perhaps fill water had VERY low CH and would have explained the drop. But, that's not the case.

Still, do not add CH as evaporation will SLOWLY increase CH in your pool on it's own. Even if it doesn't, you are in no danger with a fiberglass pool.

 

[Rancho Cost-a-Lotta]

Confirm your testing procedures first. Make sure you are using the same drop multiplier as you did for the previous tests (10x or 25x). Also make sure you're using the same sample size (10mL or 25mL).

 

[Newdude]

I imagine the rain in Ohio will counteract the CH from going up with occasional fills. Most of us in the east or north east see our CH drop. (And salt/cya too).

Foe those using 10ml samples, the 1 drop variance is +/-25 and it might appear to swing at times.

 

[datadr93]

Confirm your testing procedures first. Make sure you are using the same drop multiplier as you did for the previous tests (10x or 25x). Also make sure you're using the same sample size (10mL or 25mL).

Don't have high calcium levels so have only been doing the 25 mL/10x multiplier.

 

[datadr93]

Maybe an eventual update to PoolMath for the calcium. Seems to be a bane for number of folks since doesn't differentiate variable such as fiberglass pool.

I only see a red exclamation mark... calcium low... which in turn impacts (slightly) the CSI