Temp and CYA readings questions...

[lorngraves]

I saw in another post the JasonLion referenced temperature having an affect on CYA readings. How does that work? Upon closing last October, my pool was heated to 90 degrees and the CYA was at about 65. At opening last week the CYA is reading about 80. We have not turned on the heat pump yet and the water temp is about 62 right now. Could that explain why my readings are so different?

I have not added any CYA, the pool store that opened my pool said they got a reading of about 35 on my CYA and suggested I add some more, but my TF100 says CYA is 80...I am not going to add any more until I know for sure that I will not "overdose" my pool on it. How can they get 35 and I get 80?

 

[JohnT]

Your turbidity test can be skewed by cloudiness in the water. If the pool hasn't cleared completely yet, don't put much stock in the test.

 

[JasonLion]

If the water is cold when you do the CYA test it can read low. If the water is at all cloudy the CYA test can read high.

 

[lorngraves]

The water was slightly cloudy upon opening but you could still see the main drain's on the bottom. We have a solid safety cover. We opened it last Wed. and I did a full test. The temp was around 62-63, the water was slightly cloudy. CYA measured 80.

The water cleared up by Thursday afternoon. Now it is crystal clear. I repeated the test Sunday and still got a CYA of 80, with the crystal clear water, pool temp about 62.

So with the clear water and low temp should I assume my CYA is actually higher then 80? Oh my!! Should I take some of my water to another pool store and see what they come up with. There are about 5 local ones here.

 

[duraleigh]

So with the clear water and low temp should I assume my CYA is actually higher then 80?

No. Assume it is the same as when you closed last fall. Let the temps come up add chlorine as normal based on last years CYA.

Do your own test in three weeks or so and see what you get. My bet is it will be the same as you tested last fall (+-)

 

[lorngraves]

I really hope so!! I am kind of freaking about the idea of high CYA. I know this is horrible but I am not sure what chemicals the PB used to close it, or open it for that matter. I am assuming they did not add CYA since they suggested that I add that.

If they used a chlorine shock pack to close and open it would that add that much CYA to my pool? I did find 2 unopened packs of "Shock and Clear" when I got back after they opened it. I only have used the SWG.

 

[JasonLion]

Shock and Clear is 58% DiChlor, which contains CYA.