No, not necessarily. As I found, a constant, low level amount might double in size during the day and have half of it killed off overnight. Level is too low to be visible, but dead algae appears on the pool floor every almost daily. It could be mistaken for dirt or something else.But wouldn't the algae be visible - as in green, yellow, etc.? There is no trace of anything like that - at least that can be seen. I moreso suspect the WWM (fungus).
Thanks...just search around for any of my threads - you'll get the general idea pretty quick. I don't use sand.....DE filterPlease don't use a flocculant, whether you can vac to waste or not! It will gum up your filter and you'll have to put all new sand in it.
What is the problem with your pool? We can help.
Then it will gum up your DE filter. Flocculant is just bad news any way you look at it. Chlorine is the way to go. Listen to @Leebo -- he knows whereof he speaketh.Thanks...just search around for any of my threads - you'll get the general idea pretty quick. I don't use sand.....DE filter