Testing chlorine when shocking

I like to use a syringe to measure out the volume of the pool water and distilled water. These are readily available at the drug store for dispensing childrens medicine.

I run a SWG which recommends CYA at 60-80ppm. Using Ben's Best Guess chart this means when I do need to shock, I have to increase Cl to 20ppm.

At this level, the amount of chlorine in the tap water is almost insignificant, so I use tap water instead of distilled.

You can get large syringes At any TSC or COOP or where they sell animal supplies. Of course the needles are sold separately which is ok with me.