fighting mustard algae

[PoolDoc]

I quit after adding 22 drops of R-0009 and still hadn't turned sample red...it was green, then blue, then yellow and heading darker/to red but, YIKES, that is some high TA.

Watch this video, and retest: http://www.youtube.com/watch?v=gmpS-...ature=youtu.be

The rest of the videos are here: http://www.poolforum.com/pf2/showthread.php?17157

[Kateyru]

THANKS!!!! That was really weirding me out!!!

[Kateyru]

Hi Team,
An update and questions...test results from earlier this morning are:
pH = 7.2
TA = 90
CYA = 35
FC has been drifting down since mustard algae shock attack. My estimate of FC is 15. I had to use dilution test as I am out of reagent to use with K-2206 test.

Questions:
1) is there a way/procedure to use fewer drops of R-0871 when repeatedly testing FC at mustard algae shock levels?
2) should I continue to lower TA (by adding acid to lower pH then aerating then repeating)
3) When should I add CYA to raise it? I've added several times this summer and am surprised it is as low as 35 but I triple- checked it today

I'm hoping that I have successfully removed the mustard algae but time will tell. No more extended trips away from home/pool should help.
thanks for your continued assistance!

[BigDave]

1) is there a way/procedure to use fewer drops of R-0871 when repeatedly testing FC at mustard algae shock levels?

You can use a 5ml sample and multiply drop count by 1ppm. If you have a way to measure 5ml.

2) should I continue to lower TA (by adding acid to lower pH then aerating then repeating)

I see no reason to move your TA.

3) When should I add CYA to raise it? I've added several times this summer and am surprised it is as low as 35 but I triple- checked it today

Whenever you want to. How do you get 35ppm? Halfway between 30ppm and 40ppm?

[PoolDoc]

1) is there a way/procedure to use fewer drops of R-0871 when repeatedly testing FC at mustard algae shock levels?

If you are using the 10 ml sample, then there's no further improvment. However, you can (with practice) learn to eyeball an OTO tester, so you can use it instead. To do so, you'll need to practice by testing with BOTH the FAS-DPD and an OTO kit at the same time.

2) should I continue to lower TA (by adding acid to lower pH then aerating then repeating)

It's low enough . . . unless you want to do borates, which will make your pool significantly more resistant to algae. Info here:
http://www.poolforum.com/pf2/showthread.php?18597

3) When should I add CYA to raise it? I've added several times this summer and am surprised it is as low as 35 but I triple- checked it today

35 is pretty low -- if you can get a box of PoolBrand dichlor bags at Sams Club, I'd do that. If not, I've posted links below for Amazon. It's very hard to buy un-gooped-up dichlor otherwise. But the big question is, does your pool leak? That, or excessive backwashing, would be the only reason for dropping CYA levels. (You know you should ONLY backwash when your filter pressure increases at least 5 psi over clean pressure, right? Your pressure gauge DOES work, right?)

I emailed you links to your Pool History Chart.

Ben
================================================== ==========

+ If you need stabilizer, and have access to a Sams Club, buy their 24 pack of 1# bags of dichlor shock. Each bag will add about 7 ppm of chlorine, and about 6 ppm of stabilizer, per 10K gallons of water. Otherwise, order dichlor from Amazon:

Kem-Tek Dichlor 22 lbs

We do NOT recommend buying dichlor locally, otherwise, at least until you are an EXPERT reader of chemical labels. The chlorinating pool chemicals sold at Walmart, Kmart, Costco, and most other local stores are diluted blends, sometimes with copper and other products with bad side-effects.

[PoolDoc]

Ahh-h.

Simul-responders . . .

BigDave, I don't think there's a 5 ml marked point on the tester, is there? I'll have to go look.

[Charlie_R]

There is a 5mL mark on the tube you get with the HTH 6 way, so is it ok to use that, and have a 1ppm resolution?

[PoolDoc]

Yeah, if you can see the color change (pink to clear) that would be fine.

[BigDave]

BigDave, I don't think there's a 5 ml marked point on the tester, is there? I'll have to go look.

Yea, I saw that after I posted.

Many liquid medicine dose cups have a 5ml mark, one could measure water with that, transfer it to the test cylinder and mark the test cylinder with tape or marker.