Another CYA question

[christyst]

After resolving the issues from my previous thread, http://www.troublefreepool.com/threads/83657-New-pool-owner-weird-readings?highlight=weird+readings, my pool has done amazingly well! I ended up adding about 2 lbs of stabilizer, contents read 100% CYA. Resulting CYA level was 50 by TFPK-50 kit. Rechecked today, just because I had not tested in a while, after adding bleach last night. Readings: FC 4, TA 140, CH 175, CYA 0, PH 7.5. This seems odd to me as I thought you could only lose CYA by draining the pool? Have lost some water to evaporation, of course, but have not drained any water from pool. Would think refilling/topping off pool would not change amount of CYA present since none was drained out? I have another pound or so I could add, but wanted to see if this sounded right to you guys before I added more.
Thanks so much for all your help!

 

[jblizzle]

You are correct that the CYA should still be in the water if you are only topping off evaporation. It will slowly drop due to splash out and does break down 3-5ppm each month or so.

2 pounds would have added 37ppm of CYA in your pool. Are you sure your CYA is reading 0ppm? Is the test sample cloudy at all?

 

[christyst]

Using the black dot in the bottom of the tube test. Filled cya mix bottle to bottom of label with pool water, which was clear. Added reagent to top of label. At this point the mix looked yellowish in the bottle, but I was still able to see the black dot when the tube was full. It did not seem cloudy, just yellow colored clear water. That is what I was wondering, if it was a bad test or the cya had broken down.

 

[jblizzle]

The test should not look yellow at all so that is weird. The CYA reagent is one of the most stable, so i would not think it has gone bad either.

 

[christyst]

Should I redo the test, or not worry about it?

 

[christyst]

Ok, user error. I had used wrong reagent. Used 2003 instead of 2013. Retest result is 55.

 

[jblizzle]

Glad, there was a simple explanation

 

[christyst]

I was just reading through your pool closing info. Hoping in my area to a have another couple weeks of swimming weather here, but trying to think ahead.. Was reading in the above ground pool section that it is not necessary to completely drain and put away the pool, which is what my Intex pool manual says to do if your area gets below 45 in the winter. (mine does). So is this still ok to shock, lower water level, put pump/filter up, and cover?