About a week ago i noticed the liner was looking a bit dull, so when I brushed a thin cloud of "dust" came up. A week later that hasn't returned. I also had some dirt in the deep end and the usual place in the shallow end. I always get some sand and silt in these areas, but I vacume it up with my poolblaster with a silt filter and it stays gone for 2-3 weeks. This stuff started to come back after a couple days and I noticed it went straight through the filter of the pool blaster. Now this stuff looks and sounds like mustard algae, slight yellow/brown, brushes away but returns, and is super fine when I touch it. The problem is my chlorine demand is the same, overnite drop is 0, and I never let the chlorine drop very low. The lowest I've seen the chlorine is 4ppm If i miss a day, which is rare. I'm topping off the pool to vacume to waste this morning.
Tests this AM
Drop test 0
Any other ideas to tell if this is Mustard Algae, can you have it without an increase chlorine demand?