Why is dichlor not recommended?

[Farmingtonpool]

Just have the basic test kit. Running 5+ on the chlorine, 7.6 on pH. Water slowly getting better. How can I check my CYA levels.

[PoolDoc]

Usually, we recommend that folks purchase the K2006 kit, which allows you to measure CYA (stabilizer) levels, and accurately measure chlorine levels above 5 ppm. There is a link, to various kits available from Amazon -- usually, the preferred seller there is Amato.

Alternatively, you can take your water to a dealer. The problem is that they often use test strips, and the CYA test is the worst of a bad lot -- we often refer to test strips as "guess strips" because they are so vague in their results.

What sort of pool do you have?

[Farmingtonpool]

Gunite, 3 1/2 years old. About 30,000 gallons.

[PoolDoc]

Yes, definitely, you need a K2006 -- you not only have to manage CYA levels, but you actually need to "balance" your pool water (manage pH, alkalinity, & calcium hardness) to protect the plaster and concrete.