Pink Algae ... HELP!!

[Lisa]

I don't know how, but I seem to have pink algae. I'm finding pink spots on the sides of my pool every day ... brush and they return! I have not yet used any algaecide this year ... was hoping that I wouldn't have to.

My current numbers are:
FC 3
CC 0
PH 7.2-7.4
Alk 100
CYA 50

I just put 4 gallons of bleach in the pool .... what else should I be doing?

 

[JasonLion]

Algecides generally aren't effective against pink algae. The solution is to shock you pool. That means bring the FC level up to 16 and holding it there for a few days. To do that you need to test the current FC level and add bleach (or another chlorine source) to bring the FC level back to 16 at least three times a day. Keep doing this until the FC holds steady overnight and there isn't any CC, and then keep it there one more day just to be sure.

 

[Lisa]

Thanks for your quick reply .. now for a stupid question ... my taylor test kit doesn't go that high .... so, how can I know that it is at shock level?

 

[JasonLion]

By far the best thing to do is to get a FAS-DPD chlorine test kit, which can test FC and CC up to 50 ppm. TF Test Kits has that test available separately, as does Taylor (K-1515-A or K-1515-C).

If you have a test that can distinguish free chlorine and combined chlorine you can get by in a pinch by using dilution. Mix one unit of pool water with one unit of distilled water and multiply the result by two, or mix 1 of pool and 2 of distilled and multiply the result by three, or mix 1 of pool and 3 of distilled and multiply the result by four. This is far less acurate, and gets worse as you use higher dilutions, but if done carefully is usable.