Non Copper Algaecide And Borox

[Andrew61987]

Been having problems with my pool recently. pH was 6.8, ALK was ~120, and the pool was green with algae all over the sides, even though I cleaned it all off just a couple days before.

Chlorine stays at 5+ ppm always. Dichlor.

I added 4 boxes of Borax to bring pH at about 7.2 and 4 ounces of Super Algae Stop (which is algaecide w/o copper).

Algae was gone after 12 hours, but now the water is bluish white, I would almost call it "milky" although I can still see the bottom. The algaecide made the water smell rather bad and taste funny too. Will this go away soon? It's been a couple days. It also has a foaming problem now too when I kick around in the water. Is this the algaecide or Borax?

20,000 gal pool

temp: 82 degrees F

Remains covered except when in use.

Another question about borates:

I added 4 boxes several months ago, and I added another 4 ounces the last couple days. Do borates dissipate from the pool? Or am I getting close to the point where I should stop adding borax and use soda ash instead?

[chem geek]

Your pool probably got algae because continued use of Dichlor will add to Cyanuric Acid (CYA). For every 10 ppm Free Chlorine (FC) added by Dichlor, it will increase CYA by 9 ppm. It is even worse in this regard than Trichlor tablets/pucks since for every 10 ppm FC, they only add 6 ppm CYA. Higher CYA levels require higher FC levels to prevent algae growth, unless you use a supplemental algaecide.

The foaming problem is from the algaecide since it's a linear quat and they tend to foam. Use of the more expensive PolyQuat would be better and non-foaming, though it's better to use such algaecides as preventative and they aren't as good killing an algae bloom (though they are better than nothing -- chlorine alone is best, but if the CYA is really high a partial drain/refill should be done first).

As for Borax, the borates don't go away except by dilution (e.g. splash-out, backwashing) so you could test their level with a LaMotte Borates test strip as shown here (test strips are OK in this case, and with the salt test; for other tests a Taylor K-2006 or TF100 test kit should be used).

Richard

[Andrew61987]

The algae coincided with a whole bunch of dirt that went into the pool from some construction being done next door. Does that make sense? Do you anticipate the foaming and bad smells from algaecide to disapear?

Local pool store says my CYA is 35 but I don't necessarily trust them. Having lots of trouble finding a stand alone CYA test kit.

[chem geek]

The dirt was probably fertilized and had phosphates and nitrates which are algae food. So that would accelerate algae growth.

You can get a CYA test that measures from 20 to 100 ppm at a good price here.