Algae growing with balanced pool water

[mkmscr]

So I am a bit baffled whats going on with my pool. I keep finding traces of algae in the crevice areas that my robot pool vacuum has a hard time getting too. My specs are below and I am confused why algae is growing in the first place since FC has been perfect for my SWG pool. Water is crystal clear. CYA is also on the money. Thoughts? Do I really need to start the SLAM process? Don't really want to start raising chlorine levels with the holiday and expecting a lot of swimmers this weekend. I can never seem to get a straight answer what FC levels are safe to swim in.

Thoughts?

FC - 4.5ppm
CC - less than .5
PH - 7.7
TA - 90 (little high but not alarming right?)
CYA - 70

p.s. testing with a Taylor K2006 kit

 

[Donldson]

You answered your own question, your robot isn't getting to those areas and you probably have low circulation in that area. Areas with low circulation can get locally low FC and end up getting some algae growth.

Much like your teeth you want to brush your pool occasionally, at least in those areas where your robot isn't getting to often. That will disperse any algae and get some chlorinated water in there. As for this weekend, you can probably get away with just brushing well and maybe raising the FC a couple points. Keep a close eye on your FC to make sure it doesn't start to drop and you should be fine. If you start to notice some significant FC loss then you may need a full SLAM, but cross that bridge if you come to it.

 

[YippeeSkippy]

I'd raise my goal FC level up a notch or two and see if that helps keep it away after you brush it real good

 

[mkmscr]

Definitely agree and I tossed in a container of 8.25% bleach last night which should bump my FC to about 9 or 10ppm. Like you said, watching FC levels closely and I agree just some crevice areas probably not getting hit with my vac. I scrubbed the pool good last night, ran the pump and SWG overnight. Thanks for the feedback guys. Have a nice holiday.