Problem with mustard algae

Hi and thanks for any info....I'm still waiting to hear from Ben about my subscription account so I guess i can't post this question in any other forum until that gets cleared up. So here goes, I have been battling what I only assume is mustard algae By the way it is behaving ( poofs away when you touch it, but then returns to the same spot after some time) my questions are these: should I use polyquat for that in addition to high chlorine, i have been raising it to 15 nightly ....the pool store of course wanted to sell me yellow out? I have read that it is very hard to get rid of, and I am wondering why it keeps returning? How am I reintroducing in back in? I am waiting for the titrating agent for my 1515 kit that I purchased last year so I am relying on an oto for chlorine reading until that arrives.
My numbers are
As of tonight: fc-3
Cc- 0
Cya 35
Ph 7.2
Ta- 70
Water temp 86
16x32 in ground vinyl, sand filter ( has been on for 2 plus weeks straight)
My pool is in the sun for the whole day ...should I raise cya?
I have dichlor powder, and bleach here...
Please advise..
ps I had found last week in The front of my skimmer what looked like white water mold ( jelly like slimy stuff) removed all that and shocked to 20 for a few days...I am at a loss I feel like i am spend so much time trying to figure this out. Thanks again for any info.

Natalie

If you have mustard algae, with a CYA of 35, you need to be shocking your pool up to 30 ppm of chlorine (see the best guess chlorine chart link in my sig) and maintaining that until the algae all dies. You also need to thoroughly brush any area that might have the algae in it--light niches, ladder steps, etc because if you leave any of it living, it's just going to come back.

If your pool is in sun for the whole day, you might want to consider raising your CYA, but I wouldn't do it until you have the algae gone, because you want all your chlorine available to work on the algae. Plus, as your CYA levels go up, so does your required chlorine levels (again, check the chart).

Janet

Thanks so much for the information. Another question, how can i determine if , in fact I do have mustard algae? The pool is clear, just those few spots I see. If i put the jets pointing down at the area it doesnt form. It is on the floor in the low end and usually "settles" on the steps too. Should I put DE in the filter? What about the polyquat? Thanks again:)
Natalie

You can put the polyquat in, if you want--but I would wait until you clear up the algae, if that's what it is....polyquat will create a chlorine demand, and you need all the chlorine working that you can get, right now.

The easiest way to tell if it's algae or not is to test your chlorine levels (free and combined) at night after the sun is off the pool, and then test them again in the morning before the sun is on the pool. If you didn't lose any chlorine overnight, then you don't have algae. If you lost more than 1 ppm of chlorine, and/or if your CC is 1.0 or greater, then you have something, most likely algae, in the water.

Thanks again, so will algae be stuck to wall, floor? I guess I was under the impression that it would be hard to get off. That I would have to brush and brush it. Again, just trying to determine if this is algae or just regular dirt that is settling to the bottom.
Also, does anyone know where you could buy the titrating agents for the kits other than online?

Mustard algae is VERY easy to brush off -- but it's apparently hard to remove 100% since it tends to return to the same spots.

I'd just dose with 4 gallons of plain 6% household bleach AND 1 lb of dichlor each evening, till you get the reagent. And, brush your spots daily, preferably right after adding the chlorine.

(I'm sure that somewhere there's a pool store that sells Taylor FAS-DPD reagents, but I've never heard of one that did so.)

Will follow your advice, thank you !....So basically I'm just keeping the full bloom at bay, right? It's just puzzling that the water is clear, yet I still have these recurring spots ...... anyway the dilemma I have is that my family is going on vacation this weekend for a week, so I was going to have to have my father tend to the pool.. Should i just have him follow these instructions? It may be hard for me to explain the whole testing thing to him. ( he may be able to do simple test, but the other one may be a stretch) lol originally I was going to put 4 trichlor pucks in and hope for the best, but now nice I have this mustard algae issue, Im not sure what my best plan of action would be. Thanks again:)

Also, should I be vacuuming to waste the little spots of algae? Should I do anything with the filter sand? It has been probably 5 years since we changed it. De in filter? Thanks again for all your help

1. Do let your father follow a routine like that, but it may not need to be that much chlorine. It would be good if you can get couple of tests done before you leave.

2. Do brush / vacuum the spots. That's a BIG part of getting rid of them.

You do not need to change filter sand nor add any sand cleaners.

So do you think I should vacuum to waste?

Also, I have about 5 lbs of individual packages of cal chlor "shock n swim" can I use those once I use up the dichlor powder I have? I just checked my calcium and it's 130.. I do have a vinyl liner. The spts are definitely getting smaller .. What about backwashing, how often should you do it? As always, thanks so much!

I don't know the ingredients in 'shock n swim' and I'm skeptical about adding things I don't know about. Too many voodoo mixes out there in the pool chemical world that sometimes have things in there that you don't want in your pool.

You should backwash whenever the filter pressure rises 8-10psi over your clean filter pressure. I don't think you need to vac to waste. Sounds like you only have a few spots and not a cloudy swampy pool. 'Vac to waste' wastes a lot of water.

Quote:

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Originally Posted by PoolDoc

Mustard algae is VERY easy to brush off -- but it's apparently hard to remove 100% since it tends to return to the same spots.

I'd just dose with 4 gallons of plain 6% household bleach AND 1 lb of dichlor each evening, till you get the reagent. And, brush your spots daily, preferably right after adding the chlorine.

(I'm sure that somewhere there's a pool store that sells Taylor FAS-DPD reagents, but I've never heard of one that did so.)

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I actually found the FAS-DPD powder in a Leslies near White Plains. The clerk couldn't find a price anywhere in the system...and just gave it to me. That must be 10 years ago because it was just after my Dad passed away, in 2002. I was building my current pool and had taken down my Intex Donut for the last time.

I have trichlor tabs (4) I was going to put in for the week I was away...is that ok? My dad can add bleach periodically, and the shock I have is, "hth super sock it" it is 62.4% calcium hypochlorite, can I use that? I have that in one lb bags...I am trying to ,are it as simple for him as I can. Thanks!

The trichlor tabs will be okay for the week that you're gone--just test your pH (you need to do that anyway since you've been using dichlor, which is also very acidic) and push it up to the 7.6-7.8 range before you leave, so that the trichlor won't push it down too far. It's okay to use the cal-hypo if your calcium hardness levels aren't too high--if they're less than 200 or so, then they should be fine to use.