Mustard Algae - Help!

[Phillbo]

What about draining and using a pump up sprayer to spray the areas with bleach and let dry .. If it dries out it will die, right?

Or will it just come back again once refilled?

[PoolDoc]

It's not that hard to kill mustard algae, once the pool is drained. Spraying bleach is not a bad idea for black algae, but it's overkill for mustard algae. Mustard algae does NOT penetrate into the plaster. Simply spraying it off with a hose nozzle, as the pool drains, is more than enough.

[chem geek]

Yellow/mustard algae prefers shade so will tend to hide out behind light niches and under removable ladders. So even if you replace the pool water, you need to get into those areas and thoroughly kill off the algae or it will come back after you refill the pool unless you maintain higher than usual chlorine levels. It's best to eradicate the algae if you can.

[spbb05]

Thank you all for your responses. I apologize for the delay in answering. I thought I had email notification set up and apparently did not.

I expect the kit to be here by Tuesday or Wednesday. I've brushed a few times and it is only coming back only in few spots and in smaller areas. I've also used 3 gallons of 8% 2x times since posting. I'll report tests as soon as possible.

Any hints or tips on using the the test kit for the first time user?

[spbb05]

The K2006 test kit arrived and the results are:

FC - 11.5
CC - .5
PH 7.6
TA 150
CH - 280
CYA -100+ - the black dot disappears at the top of the letters CYA on the tester.

[PoolDoc]

Sorry for the slow answer.

With FC > 11 ppm, you may have regained control of your pool. If not, do this:

1. Retest your CYA, using a 50:50 dilution of pool water with tap water. Multiply the results x2 for your actual CYA level

2. Read the Best Guess page, linked in my signature, or found here: http://www.poolsolutions.com/gd/best...ine-chart.html

3. Adjust your chlorine level upward to an appropriate level.

4. Stop using stabilized chlorine (trichlor or dichlor) and use only bleach. with CH = 280, you probably don't want to use calcium hypochlorite either, though there is a way to do so IF (a) you have a sand filter, (b) a working skimmer, and (c) can make SURE that any chlorine feeder located upstream of the filter is EMPTY.

[spbb05]

Thank you Ben. The pool looks a lot better and I'm not seeing any more algae.
I retested the CYA as recommended and its 160.


I have more questions about stains/calcium build up on the floor and doing a partial drain to drain reduce cya and CH.

Can I ask on this thread or should I start a new one?

Thanks again!

Steve