My numbers...

[ironmanix]

FC - 2, TC - 2, CC - 0?
CYA - 50
PH - 7.8
TA 100-110
CH - 170

Per the Taylor test doc, CH should be in the 200-400 range. What does CH affect? More importantly what does LOW CH affect?

 

[ironmanix]

And help me further understand Combined Chlorine...

 

[frustratedpoolmom]

CH isn't important in a vinyl pool. If you have high CH, combined with high PH, you can have scaling issues, for starters. You are fine so don't worry about it.

CC is something you want to always be .5 or less. Anytime you see it higher than .5 you should raise the FC up a bit higher for a few days, leave it uncovered cuz sunlight helps destroy CCs; and if it goes higher than 1 you should shock the pool.

Your FC is too low for your CYA level. Refer to the chart in my sig. Always add enough bleach each night to reach your "target" to keep the FC above the "min".

Your PH is a little high. Use some muratic acid to lower the PH down to 7.4. (never add bleach and acid at the same time though.)

For more info - ABC's of Pool Water Chemistry

 

[zea3]

Combined chlorine is the "waste byproduct" of chlorination that you need to get rid of by shocking if it is greater than .5ppm. CH is not as big a concern in a vinyl lined pool. In a plaster pool low calcium levels will cause the water to draw calcium out of the plaster. This will cause the plaster finish to weaken and age more quickly and degrade in appearance.

 

[frustratedpoolmom]

Sometimes especially after spring openings just raising your FC a bit higher than normal and leaving the pool uncovered will lower CCs - you can shock but sometimes they'll come down after a few days.