Quote Originally Posted by kickurasin View Post
well how do you keep this level below 100
mine this spring was 348 so i dumped out 1/3 water now it is 49
how do i keep it under 100 cya
Take a look at your method of testing, your numbers here don't look right.

My understanding is that levels above 150 or so are difficult to test accurately. Also, if you did have 348 ppm of CYA taking 1/3 of the water would only lower it to 232, so your original levels were likley much lower.

As stated above however, if CYA levels pose a problem for you (getting high - above about 60-80) then you should discontinue using Trichlor or Dichlor chlorinating products and resort to an unstabilized product like standard 6% ultra bleach or other economical Sodium Hypochlorite solution (i.e. liquid shock - 12.5% NaClO)

I personally use a combination of bleach when it's convenient, and trichlor tablets when it's not (or I need to raise my CYA). That keeps my CYA level below 80 every year. Over the winter I tend to have to pump out at least 7000 gallons from rain fill, that helps with lowering CYA over the winter as well.