Best Guess Chlorine Chart

The PoolSolutions Best Guess Chlorine Chart is here:
best-guess-swimming-pool-chlorine-chart.html

PoolDoc

Update due!

The table still works. But time, experience, and ChemGeek's research have laid the basis for percentage based approach.

Doses & Levels

• On outdoor pools, maintain a minimum 1.5 ppm chlorine level regardless of CYA
• Once CYA is above 30 ppm maintain, 5% of CYA ppm.
• Once you are SURE the pool is well-controlled, you can experiment with dropping as low as 3% of CYA . . . but not below 1.5 ppm
• Weekly it is wise to 'shock' with a 10% dose
• At the first sign of algae, go 10%.
• Mustard algae make a level of 25% or even higher.

Modifications:

• Pools where algae is NEVER a problem can operate at 3%
• Borate levels above 50 ppm will often allow operation at 3% or lower.
• Sustained phosphate levels below 100 ppb (0.1ppm) will allow very low levels.

Both high borates and low phosphates will also REDUCE chlorine consumption, though I don't yet know how much. HOWEVER, even if you doing everything right, don't operate below 1.0 ppm FC. Controlling algae is NOT the same as santizing or killing 'germs'. So be safe, and maintain 1 ppm FC no matter what!