Hi chemgeek.chem geek said:Yellow/Mustard algae looks like yellow/mustard colored dust -- it generally does not stick very hard to pool surfaces. It takes more chlorine to prevent it and especially to kill it than for regular green algae that is more common.
Hi chemgeek (thanks for the response!)chem geek said:Did you ever check the CYA level yourself after you got your own test kit? Maybe the 32 ppm CYA from the pool store was inaccurate. If your true CYA level were higher, then a higher FC would be required. I believe one of the first user's on the Pool Forum reporting algae hit it with 35 ppm but had a higher CYA level of 50 and we also didn't think of lowering the pH first to make the chlorine effective (so his FC used the "1.0" column in my chart instead). That's my best guess at this point unless what you have isn't algae. We also don't have as many cases with this algae -- we've got quite a few, but not as many as green algae -- so it's possible some circumstances need higher FC than others. I'm betting that the CYA is actually higher, however. You know, if you had a microscope you could look at the stuff and it would be pretty easy to distinguish the two. I wish there were a simple test to use to distinguish -- can anyone think of something?
You are almost always going to have some dust, pollen etc. landing in the pool that will settle in the bottom. Sometimes it's residue from the decking that gets in the water. The wind carries a surprising amount of crud along with it.holemania said:gone fishin'
(4) sediment introduced from well water? pollen or dirt introduced to the pool itself (not from the filter)...we've had a few wasps/yellow jackets/dirt dobbers flying around, some of them building their mud nests...probably not likely...lol.
not sure how to first approach this....don't really want to tear the filter apart and inspect laterals if i don't have to....