Rather than shutting off the pump overnight, bypass the filter and leave the pump running overnight. This will help circulate the chlorine and consume more of the goo. In the morning vacuum to waste if you can. Keep adding chlorine to hit FC of 15.
If I follow you, that is not correct. From the article in Pool School....The procedure I've been following is to check FC level every hour and the add 2 128 oz jugs of 6% bleach as calculated on the pool calculator to go from 0 to 15 FC. So far every hour it has been 1.0 - 1.5 FC. Does that sound right?
For example, if you test and your FC is 8 ppm, you should add 7 ppm of FC (Not two jugs) so your FC returns to 15 ppm.SLAM:
Measure the FC level
Add enough chlorine to bring FC up to shock level (or a little higher)