removing the cloud

[aylad]

Here is the method that was posted long ago by another mod, CarlD, for checking the strength of your chlorine..
(Begin copied material)
Put ten liters of tap water ( That's 5 soda-bottles full) in a 5 gallon bucket.

Test that water for chlorine using the FAS-DPD test to get a chlorine baseline (you may have some).

Then I take a 1 ml eyedropper full of the LC or bleach I'm testing and put it in the bucket and mix it up.

(1 ml in 10 liters of water is the same as putting 1 gallon of LC in a 10,000 gallon pool -- it's 1/10,000th. )

I then measure the bucket with the FAS-DPD test just like pool water. Of course, subtract any chlorine you measured in the tap water.

(End copied material)

One gallon of 12.5% chlorine should add 5.4 ppm of chlorine to 23K gallons. It is possible that the chlorine is being eaten up by algae, but not at that rate. 10 gallons should add around 54 ppm, and if you can't see visible algae in the water, there's no way it's eating up 49 ppm of chlorine before you can measure it. Any chance there's ammonia in the water, or hvae you added polyquat or something else that can create such a big demand?

[BigDave]

Does the pool have a strong "chlorine" smell? Have you lost any CYA?

There've been a couple posters on the forum this summer (and many in the spring) that had CYA to ammonia conversion in a very short time in an unkept pool. This would create a large chlorine demand.

[essikr]

It's nice to have this support ,thanks. I tested the chlorine and it was higher than 5.4 but I may have used more than 1ml. So the chlorine is good and the test kit must be OK. Just did a water test,there is no chlorine smell but I did see a trace of algae near the step.The water is clear. Do I need to put more liquid in???
Chlor = 4.0 (was 5.0 yesterday)
PH = 7.2 added box of Borax
CYA = 60 (it was at 70)

[aylad]

You need to get it up to shock level and hold it there until the water clears and until the algae is gone. You'll know when it's time to let it drift back down when you can measure chlorine at night and in the morning before the sun is on the pool, and not have more than a 1 ppm drop between the two measurements.