My mustard algae battle and victory

[Pamsel]

Karen, I do have some staining, but I think it's from the high iron content in my fill water, rather than from the algae. I can't be sure, but I don't think the algae leaves stains.

[brent.roberts]

Congratulations on you persistance.

On another thread with another soul that had a stubborn case I suggested shocking as soon as the sun was off the pool in the afternoon and checking again just a few hours later ... before going to be.

I reasoned that if the pool is heavily loaded with organics there would be a very fast drop in the FC levels very shortly after the shock dose, and that by morning the levels had dropped off enough that things were growing again.

Fortunately, I have never had a visitation from a stubborn algae and could not test the idea, but your case and the method you finally got to, lend some support to this idea. I am thinking that we might need to fine tune the suggested method used to fight an algae bloom to short cycle the retesting and raising the FC levels compared to the proceedure that has been generally suggested.

1) find the break point needed after testing CYA etc and use bleach calc to get the right does.
2) test withing a few minutes of adding to make sure you got it right.
3) test again withing a couple hours to see how fast it is dropping and repeat the process. The faster the retest and re-load to shock levels the faster the algae will be killed.
4) keep it up until the FC levels show little change in retesting after sunset to take sun breakdown out of the equation.

Your experience may have been a turning point in the methods we use.

[ivyleager]

Pam,

Kudos to your persistence. A lot of folks here were rooting for you.

I noticed you have a vinyl liner....did the VERY high chlorine level bleach out or do any other damage to the liner?

Also, what was your CYA prior to this algae problem and what is it now?

CaryB

[Pamsel]

Thanks everyone for your support and good wishes!

Our vinyl liner is old and probably will need to be replaced next year - it's starting to pull away from the side and getting some cracks around the upper edge. (We're limping it along with simple repairs as long as we can.) So I was more concerned about killing algae than bleaching the liner. I do think it faded some, but it was already somewhat faded - the edges where the side meets the bottom are quite a bit darker. But it still has enough color to give the pool a nice light blue color and that's a whole lot prettier than green!

I started out with no CYA but now it's around 40 - have not checked it since last week.

[ivyleager]

I started out with no CYA but now it's around 40 - have not checked it since last week.

Okay, was it zero at last seasons closing? I'm wondering if your algae bloom decomposed all of your CYA.

CaryB

[Pamsel]

To be honest, I never heard of CYA until I found this board a few weeks ago. I have no idea what it was at close, but I used the pucks in my chlorinator all last season, so it could have been high. I know I had a high chlorine demand last summer and I had algae growing in August. I really didn't know didly-squat about my pool and how to properly care for it before finding this forum, so didn't know how to kill the algae either. I think we used the copper algaecide before closing, but if I remember correctly, it was not clear when we closed it. The "pool guys" who closed it said it was not a problem. I think that all contributed to the big problem I had this spring.