Please help with algae spots!

[danamomof8]

hi,
i've just started using my new tfp test kit, along with the pool calulator. everything's been going good til now. we have algae spots, about 15 were scrubbed off yesterday. water looks clear and sparkly though.

here are my numbers:

FC 3.5
CC 0
TA 110
ph 8.2 (adding m.a.)
ch 250
cya 50
borates 80 (can't explain how this happened, added less than it was supposed to take to get it to 50)
salt 2850

i also tested with the tester for chlorine with the ph tester/it said 5, but when i tested with the other, it was only 3.5, but it didn't show any cc.

if i understand correctly, i need to shock to 29 fc, how long do i maintain this level? i will continue brushing also.

any ideas what is off on my numbers that let the algae come in?

thanks for any advice in advance.

 

[Rangeball]

You've got a great test kit. I'd trust the drop based chlorine reading. The other color based is more subjective.

If you have no CC I wouldn't worry about a few algae spots. You've brushed and exposed them to a free chlorine residual and they are dead and gone. I wouldn't shock if I were you, and don't every time I see something similar. I just brush it, and watch for CC.

I would get your PH down, as chlorine is more effective at lower PH levels. (if you have SWG this will most likely continue to drift up so I'd target a lower number, like 7.2).

With your CYA of 50 ppm I'd double check Jason's calculator to see what range you should be holding FC in. My gut thinks your a bit low and should probably be between 4-8, but double check this with the calculator. Wait a minute, just caught the salt level so if you have SWG you're probably ok

Only way to lower borates is to exchange water, but that will also alter some of your other readings. I have no idea what if any side affects there are from elevated borates.