CYA test

JFP

Member
Aug 9, 2007
19
#1
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
9,448
SW Indiana
#2
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

#3
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
#4
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
9,448
SW Indiana
#5
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
37,879
Silver Spring, MD
#6
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.