Will adding borax to 50ppm kill Mustard algae

[fuelman]

BUMP for answer to above

[CarlD]

You know, you could simply take our standard route and raise your FC to shock levels and keep it there until your pool sparkles. Use bleach or Liquid Chorine for that.

First, lower your pH a bit to 7.2 or 7.3. Chlorine is more effective the lower the pH but too low has other issues.

Shock your pool with bleach until FC reaches 15ppm and keep it there, checking it twice or 3 times a day. Brush and vacuum your pool everyday.

Expect it to take a week to 2 weeks to clear. Since you haven't done this, I suggest you do this BEFORE you play with copper or bromine additives. Notice that after you use bromine, you have to use lots and lots of chlorine just to get rid of the "fix"--the bromine. IMHO, it's better to use the bleach to kill the algae.

My reason for this is we have a tried-and-true method that has worked for thousands of people. If it works, (and it usually does) then it's the easiest and most reliable way to clear your pool. If it doesn't work, then it's appropriate to seek more drastic measures, like the bromine algaecide or addressing the TDS or phosphate levels.

Once the algae is dead and gone and your pool is sparkling THEN you should add PolyQuat to inhibit further growth. It's sometimes called Mustard Algaecide, or black Algaecide--whatever. Look at the ingredients. The SOLE active ingredient should be Poly....<something long>..... 60%. Whatever they call it, if it's Poly....60%, that's PolyQuat.

If it were me, I'd raise the pool to 15ppm, add the entire quart, wait 48 hours, then check the FC (it will have dropped ALOT) and then shock again to 15, and consider it done. If it were me.

You can swim in the water at that level, but wear old bathing suits because they will fade.

[Tredge]

Borax "Helps" and in my experience it does a great job. Certainly better than all the algecides I've dumped dollars into in the past. I dont need to keep insane levels of chlorine anymore since 50ppm borax.

But thats all it does. Helps.
Chlorine, proper PH and CYA levels are what does the heavy lifting and if you don't have those stable at least twice a day all the borax in the world isnt going to keep the algae away.

My advice is to add the borax to 50ppm and get your Chlorine much much higher and KEEP it there till the algae goes away.
After that my guess is that your current chlorine levels and borax will prevent the problem from recurring.

[KirstenHW]

How does one test for Borax & dissolved solids levels? I have the Taylor kit k2006 kit.

[waterbear]

fuelman, I am confused a bit by your test results. If you don't have a SWG then why are you testing for salt at all?
I am also a bit concerned by the fact that you have no CC yet you think you have mustard algae. If there was mustard in the water you would have some CC. How was your water tested? something does not seem right.

[fuelman]

confused a bit by your test results. If you don't have a SWG then why are you testing for salt at all?
I am also a bit concerned by the fact that you have no CC yet you think you have mustard algae. If there was mustard in the water you would have some CC. How was your water tested? something does not seem right.

Waterbear, My neighbor has a SWG and a very expensive Taylor K-1741-C test kit. The Mustard algae turned out to be pollen. As for the salt test he just tested it out of habit. The phos level and the TDS level was tested at the pool store.
I have been using a lot of bleach lately, 1/2 gallon a day. Seems more than I used last year. Do you have any idea why?

[waterbear]

Probably the pollen. It is an organic that will increase the chlorine demand.

[waterbear]

How does one test for Borax & dissolved solids levels? I have the Taylor kit k2006 kit.

Best test for borates for home use is the LaMotte borate test strips. They are far superior to the AquaChek and Protream strips.
TDS is a bogus measrement for the most part. The only way to test for it is with a conductivity meter, which is an expensive piece of equipment. Don't worry about TDS.