Quote Originally Posted by wilsol4 View Post
OK, here are my pool readings.....any advice is appreciated

Free Chlorine 6.4 ppm (two readings to confirm)
Combined Chlorine 0.4 ppm (two readings to confirm)
pH 7.4
Calcium Hardness 40ppm

Please advise.
Have you gotten a stabilizer reading? (also called CYA). Your Free Chlorine's effectiveness depends on your stabilizer level.
Your pH is fine--don't try to adjust it.

You really only need to measure your FC and CC using the 10ml mark, not the 25ml one, which wastes your reagents.

Without the CYA, I can only guess what you should do, which would be to shock the pool to get rid of the CC. But, without the CYA level, I'm guessing at how much.

But, for future reference: 1 gallon of 8.25% bleach will increase your FC by 11 3/4 ppm. 1 gallon of 6% bleach will add about 8 1/2 ppm of FC. If you want to add only 4ppm, use a half-gallon of 6%. etc.