CYA test

JFP

Member
Aug 9, 2007
19
Like others when testing for CYA the black dot never disappears! What is the concern over the test results not actually being zero? I don't understand.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,614
SW Indiana
If the black dot never disappears, you have little to no CYA. This means your chlorine will drop pretty rapidly when the water is exposed to sunlight.
 
G

Guest

You don't want your CYA to be zero. If you have an outdoor pool and you are manually chorinating (as oppsoed to using s SWG) then you want your CYA to be 30-50 ppm.
 

JFP

Member
Aug 9, 2007
19
I read somewhere that the pool CYA might not really be at zero; even though even though it indicates zero. Concern?
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,614
SW Indiana
I don't know how it could unless you've just added CYA and it hasn't dissolved yet. A little cloudiness to the water can throw the reading off by 20 or 30ppm to the high side, but I don't know any way the test could read it too low.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
CYA can sometimes read zero when it is at 20 or below. If it reads zero, you don't have very much CYA, though you may have more than zero.