I have had my PebbleTec pool for about nine years. There has been a consistent problem in that if I let the FC go below 5, I start to get growth in the pool. According to various tables on this site and also other places on the web this should not be so. Anyway last week I started to get green algae growth on the pool walls. I used my normal plastic bristle Wall-Whale brush to brush them down. However I noticed that after brushing the green areas, they were still green!
I have a small wire brush which I then used on those spots. The wire brush did remove the algae. It appears that the growth in the cracks of the PebbleTec finish will not be removed with a standard plastic bristle brush. I when down to my local pool store and purchased an 18" wire bristle brush which I then mounted the Wall-Whale parts to. This eliminated all of the issues. Also of note at least for two brushings after removal of all visible algae, white dust could be seen rising from the back of the wire brush.
It looks like growth can and will settle into the cracks and crevices of the PebbleTec finish. So if you have a PebbleTec or similar finish I would recommend going to a wire brush.