CYA of 25 after a year of Trichlor tabs?

[kwolfe]

Hi everyone. Well we are in year two of our new pool and loving it. (I will post pics once the new grass grows in )

I am planning on following the BBB this year. I did not purchase a new Nature 2 cartridge or more trichlor tabs, however my garage has 12 bottles of bleach in it.

I opened the pool in the begining of April and didn't really do much to it. Well, with all of the dirt and stone I had been moving (and lack of chlorine) the pool got a little cloudy so I decided to shock it. I did the calc and for 29k gallons I putin 8 gallons of 8.75% bleach. The next day, it looked great.

My calc was based upon having a CYA of 70 (so I thought I remembered). I rechecked the CYA yesterday and today...twice) with my Taylor K2005C that I bought last year. These are my results:

FC = 4
TC = 4
PH = 7.1
CA = 280
TA = 90
CYA = approx 25 (The vile was filled about to the top when I couldnt see the dot anymore which was a little about 30)

My question is, after a year of using trichlor tabs, is it possible to have CYA of only 25 after using trichlor tabs all last year? If so, then I am darn happy Just so you know, they started the pool on trichlor and did not add anything else when the start up guy came.

 

[Richard320]

It's possible. Here's just one of many threads discussing the phenomenom. Try the search function using disappearing and then fine tune it using winter. CYA is too short a word, and too common anyway, to be any use in the search.

 

[kwolfe]

It might make sense since when closing the pool, we did drain the water down below the skimmers (solid loop lock cover so no snow or rain). Also, I backwash the DE every month + rain + plus splashing kids running back and forth to the diving board.

Gues I should put a couple of pucks in the chlorinator and get to 30-40.

 

[Bluechip]

Your pool is about the same size as mine and one 7oz tricolor puck adds 1ppm of CYA to the pool. So you should be good for more than a couple if your current CYA really is 25 or so.