Long time member (since 2009) but very infrequent poster/visitor due to the fact that the methods here just work and I haven't needed a lot of help.
This year however, I cannot seem to get rid of the "green hue" in my pool no matter what I try and I continually will get a fine build-up of "green matter" on the bottom of my pool that no amount of daily brushing and vacuuming will keep from coming back.
I've done several SLAMs and I pass OLCT with no issues which means, to my understanding, I don't really have any organic growth going on inside the pool.
This is leading me to wonder/think that perhaps my sand filter is just retaining some of this organic matter and not filtering it out completely and just sending it back through my return. Is this typical. For a bit of history, I purchased a new sand filter 4 years ago and have never replaced the sand as my pool guy told me you dont need to and it's actually better to leave it in there packed tight.
I do normal backwashing when required and have only once done a vacuum to waste, just this month in an effort to try to clean up my current issue. I'm starting to wonder if I need to do some kind of deeper cleaning on my filter which lead me to this thread on deep cleaning a sand filter.
I have never done something like this, or even opened my filter. Is this possibly my issue and something I should pursue?
Here are the stats if anyone is curious:
18ft above ground, round pool.
~ 7900 gallons
FC: 5-7 depending on the day