Trouble measuring Calcium Hardness

[thegizzard]

I’ve tried to read up here but I think I need some tips on how to measure calcium hardness with the Taylor. I continue to measure low even after adding Hardness Plus.

I use a speed stir and add drops very slowly but it seems like I am measuring about 100ppm low.

Any recommendations?

 

[Jimrahbe]

Giz,

Low compared to what?

Are you running the 10 ml test or the 25 ml test?

Are you adding drops until the color no longer changes?

How long are you waiting to test after you add the CH up?

Thanks,

Jim R.

 

[ajw22]

What makes you think you are 100ppm low and not correct?

 

[thegizzard]

The 10ml test CH = 200
The 25ml test CH = 210

So about the same and consistent.

I have added a lot of Calcium Chloride over the last couple weeks and Pool Math is predicting larger increases in CH then my Taylor results show. Hence my doubt.

That said there has been a ton of rain and my pool actually overflowed before my auto drain was fixed. So maybe I am worried about nothing.

I am trying to be really careful with CH. PB said the new plaster pool CH will rise by itself. So I was being extra careful with my additions. I’m on Day 27 now so I am ready to switch to Pool Math guidelines from PB starter guidelines.

Given the acceptable CH range in Pool Math, I assume there is little risk in me adding more Calcium Chloride to get CH ppm > 300.

Ill do that.

 

[revitup]

Have you noted an abrupt drop in FC level with the calcium chloride additions?

 

[thegizzard]

I have not.

As of last night I am up to CH = 300. I will get it to 400 and leave it there.

 

[Texas Splash]

You might also check your CYA and salt levels to see if they have also dropped. CH, CYA, and salt don't normally drop quickly unless there was a change in water or a leak. The overflow might have something to do with the drop. Once you have confirmed your CH, I would get the CH to at least 250 and keep the pH in the 7.6- 7.8 range.

 

[IMissNimoy]

Gizzard,
I'm just south of you and we had 4 inches of rain in December. November had very little rain and I heard my auto fill kick on a few times. Depending on where you are in Charlotte, I bet we have the same surface water source (Catawba/Broad) whose hardness seldom exceeds 40ppm. Any chance this is just a dilution issue? I also struggle to get hardness to increase at the levels pool math says.

 

[Newdude]

Hey Gizz !!! For you or anyone finding this thread in the future, simple reminder to mix well before any testing. It seems so simple but it's often overlooked. 20 mins of the pump on should be plenty.

Shameless plug with reason #26 for 24/7 operation. One less step to do here.

 

[thegizzard]

Gizzard,
I'm just south of you and we had 4 inches of rain in December. November had very little rain and I heard my auto fill kick on a few times. Depending on where you are in Charlotte, I bet we have the same surface water source (Catawba/Broad) whose hardness seldom exceeds 40ppm. Any chance this is just a dilution issue? I also struggle to get hardness to increase at the levels pool math says.

Agreed, we had a ton of rain and my pool actually flooded. I suspect either my pool size estimate is off... or I replaced a lot of water.

I am currently at CH = 275 ppm. I ordered 50lbs of Calcium Chloride as Pool Math says I need another 22 lbs to get to CH = 400. I will do 10 pounds at a time and see how it goes.

Pump on 12 hours a day + freeze protect and I check chemistry after a few hours minimum... usually the next day.

 

[revitup]

Agreed, we had a ton of rain and my pool actually flooded. I suspect either my pool size estimate is off... or I replaced a lot of water.

I am currently at CH = 275 ppm. I ordered 50lbs of Calcium Chloride as Pool Math says I need another 22 lbs to get to CH = 400. I will do 10 pounds at a time and see how it goes.

Pump on 12 hours a day + freeze protect and I check chemistry after a few hours minimum... usually the next day.

Please check FC immediately before adding the calcium chloride and then after. It would be interesting to note if there is a significant FC drop after the calcium chloride addition as has been observed in other similar instances.

 

[thegizzard]

Please check FC immediately before adding the calcium chloride and then after. It would be interesting to note if there is a significant FC drop after the calcium chloride addition as has been observed in other similar instances.

Ok. Calcium arrives tomorrow.