trying to get rid of black algae

[tulsapool]

First post...
having huge problem with black algae this year.....have tried black algacide and 8lbs of 65% cal hypo.....looks alot better....i do brush at least 1 a day...have been advised to use pool-tec....
15,000 in ground kidney pool
ph-7.2
cl-3
cya-40

should i nuke it again with chlorine?
thanks

[PoolDoc]

Nothing you do will get rid of it quickly*. You can kill the top layers, and it will come back almost instantly, when you stop. Instead, do this:

1. Get a K2006 test kit, if you don't have one (Link in my signature). There are NO strips that test stabilizer accurately.

2. Read the Best Guess page (link, also).

3. Begin dosing with chlorine at the shock level . . . and KEEPING it there for extended periods (2 weeks?)

4. Brush the spots carefully ever couple of days.

5. Using borax may help; it does help with green and mustard algae, and once you've added borax, it's there, except for leaks and backwashing. On your pool, you'll need about 14 boxes of 20 Mule Team borax + 4 - 5 gallons of muriatic acid to reach 60 ppm borates.

*Nuking it with trisodium phosphate (detergent) + borax to pH to 8.5 + bleach to 30 ppm + 20 ppm ammonia, held for 48 hours *would* probably clear it up. But it would leave your pool a mess, after. It wouldn't kill you to swim it it, but it sure would leave your skin stinging and your eyes burning. (Mostly from the monochloramine that would form, not the high free chlorine) (Since some people can't tell when I'm being facetious, I'll add this: I'm not serious; do NOT do this!!)