In-ground pool, 73.000 ltr (20.000 US gallon), Salt Water Generator, Sand Filter, tiles, cover.
I had a guy maintain the pool the past year and half but since last October I have been maintaining it myself. I had some trouble keeping my FC in the charts (the test strip would always be white, indicating no FC at all) but I have added some cyanuric acid and now FC is within limits.
Both pH, FC, Combined Chlorine, and TA are within limits. I have never used algaecide in my pool.
However, a couple of weeks ago, I started seeing something that resembled sand in pool. I thought it was coming out of the inlets. Since my pool is always closed with the cover except when used, i know it was not coming from outside (e.g. Pollen). I would clean the pool and close it and it would reappear when i re-opened it.
Eventually i managed to scoup some of this into a small bucket and took it out. Its soft to the touch (so it points to algae) and its color is brownish-reddish.. I snapped a few pics of this algae..
I used algaecide and tried to keep the FC levels normal but that thing wont go away.. I can say that it slowed down the growth, but it keeps coming back... based on my research, it looks like its mustard algae.. any ideas?