How aggressive is mustard algae + the black algae woes

[foobert]

Hello from a long timer lurker here at TFP.

In Jan 2012, I bought a pool that happened to come with a house and a small slice of property. Dispite my utter neglect those first 6 months, I'm happy to say that I never let it turn green and we've become pretty good pals since then; especially after I automated the bleach additions.

I'm fairly certain I have mustard algae -- large, blotched areas that have a yellowish-brown haze, predominately on the south wall (i.e. shaded). It fairly easily brushes off into a cloud, but, my polaris sweeper does NOT pick it up (i.e. not dust/pollen). My only uncertainty is that it takes about 1-2 weeks to come back again. Is mustard algae that slow growing, or am chasing something else?

My plaster is very old and has flaked in a few spots. The edges of the flaked plaster tend to harbor black algae, for which I'm on a brushing routine to keep that at bay.

Water is sparkly clear. My chlorine consumption is low and stable. OCLT is <0.5 ppm. Full chemistry is here.

Assuming I do have mustard algae, I'm looking to add borate after I get my TA down to ~60-70. After that, do yet another mustard level SLAM and this time actually remove the light form the niche

Thoughts?

 

[woodyp]

Re: How aggressive is mustard algae

Your OCLT at <.5 tells me it doesn't act like mustard algae....but in all other respects, it sure sounds like it to me. I'm sure we'll get other opinions.

 

[imwarren]

Re: How aggressive is mustard algae

Try the onclt at shock level or higher that how I dignosed my mustard a few years back something about it be more resistant at lower fc levels it doesn't consume the fc

 

[duraleigh]

Re: How aggressive is mustard algae

When the algae appears, it is not clear to me what you are doing to get rid of it.

 

[foobert]

Re: How aggressive is mustard algae

Dave -- for the last 2 months, I have simply been brushing the south wall every couple of weeks and maintaining the target level FC of 4-6ppm.

Before that, I have done the mustard level SLAM process several times, but, I admit that I have never pulled the light out as called for. Mostly for my efforts I have been rewarded with a hefty chlorine bill compared to the last few months of not trying to fight it.

 

[woodyp]

Re: How aggressive is mustard algae

Have you also "chunked" all your pool toys, pool pole, nets, vac hose, family dog, etc. in while at mustard algae shock level and machine washed all simsuits? Trust me........it matters. It can take on Zombie like qualities.

 

[foobert]

Re: How aggressive is mustard algae

Indeed I have.

What I can't do is keep the ducks out that show up every now and again. I'm sure they are bringing all sorts of lovelies from the nearby ponds with them. Another reason why I want to get borates in before going through the process again.

 

[JohnN]

Re: How aggressive is mustard algae

Definitely pull the light if you haven't already. There have been quite a few posts recently, where the light was holding up the whole process. Just look here: think-i-may-have-found-my-fc-demand-issue-t65957.html
Granted, it sounds like you are passing all of the tests. but it can't hurt to check the light.

 

[duraleigh]

Re: How aggressive is mustard algae

Your first and best solution (and cheapest) to prevent and kill algae is chlorine. The next best is chlorine, as is the third best.

Do not look for borates to be a "magic bullet"....it is not....adequate chlorine is pretty close, though.

 

[foobert]

Re: How aggressive is mustard algae

JohnN -- thanks for the pointer on the light niche. Good to know what I'm most likely in for and I'll be sure to document what I find in mine this weekend...

Duraleigh -- I understand your point -- that's partly why I went through the trouble of building the database to methodically track chlorine additions and subsequent test results to have a record for my own confidence that I really have been maintaining target FC's or greater. But, from my reading here, the "target" FC recommendations provide an inadequate defense against mustard algae. If this "zombie" algae get's reintroduced from the ducks, or visiting friends, or any other possible vector beyond my control, it sounds as if I'm hopeless to prevent it from taking hold by simply maintaining target FC levels. Please correct me if I'm wrong on this.

Thus, my rationale to look at borates -- not as a silver bullet to kill my current crop of algae, but as a long-term defense measure afterward. Am I over thinking this?

 

[duraleigh]

Re: How aggressive is mustard algae

Am I over thinking this?

No, but I think you are overlooking that you probably have never quite killed the algae thoroughly......that's what the SLAM process is for.

Because you indicate you have done it several times, did you meet these criteria when you stopped the SLAM?

1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.

Another factor for you to consider is the flaking plaster. Algae LOVES hidey holes where it can get away from that bad ole' chlorine and then return to the open pool water when the opportunity is there.

Do not think your algae is unique. There are between 7,000 and 30,000 (I don't know which number is correct) species of algae and they all share a common enemy.......chlorine.

If that was my pool, I would SLAM the pool to completion and then maintain my FC at 50% above the normal values we publish for another week or so, then let FC drift down to normal.

When was the last time your checked CYA and are you testing it yourself?

 

[foobert]

Re: How aggressive is mustard algae

Yes on all 3 counts when doing the slam procedure.

Yes on doing all the testing myself. Most recent CYA test was from 2013-07-26 15:59.

OK. Plan of attack:
1) Clean out the niche and leave it open and in the water at least through step 2)
2) Do full complete Mustard SLAM w/ all extra stuff thrown in the water as well.
3) Maintain +50% higher FC target for 1 week
4) Go back to normal FC target levels
5) Wait a month and see what happens.

Thank you for helping confirming that what I'm seeing is representative of how mustard algae behaves. I know this must all seem horribly repetitive for the owner/mods of this site, but, I do greatly appreciate your input.

 

[duraleigh]

Re: How aggressive is mustard algae

What I can't do is keep the ducks out that show up every now and again.

Remington and Winchester market a very effective duckicide in varying sizes. (kidding, kidding)

They really should have little effect unless they take up residence.

 

[foobert]

Re: How aggressive is mustard algae

I personally use the Mossberg branded duckicide delivery system, but, my back neighbors get upset about the residual over-spray

:lol:

Cleaned out the niche -- found lots of powdery silt and a dime-sized colony of greenish/brown algae growing on some plaster slop stuck to the very back of the niche. I didn't chisel out the plaster slop, but, the rest of it cleaned up very nicely.

I've partially elevated the FC for today, but will give it the real grief in the later afternoon after the sun is a bit more favorable.

 

[foobert]

Re: How aggressive is mustard algae

My pool is in full sun exposure. What's the word on trying to maintain full shock-level FC throughout the peak of the day? Is it it OK to let it fall off from full level (but, obviously not below "target" levels) and then re-establish full-level again in the late afternoon?

At 17ppm level at bedtime last night, my OCLT was 3ppm. So, I've still got algae consumption.

 

[JohnN]

Re: How aggressive is mustard algae

Any time you drop below shock level, it will make the process take longer. I would try to stay at shock level all day.

 

[foobert]

Re: How aggressive is mustard algae

Status update: OCLT passed last night. Held 17 ppm FC throughout the night, no CC.

Phase 2 has started -- 24+ hours of 24 ppm FC.

9.2 gallons of 12.5% bleach consumed thus far.


So, what have I learned --

1) imwarren nailed it: no chlorine consumption at target levels doesn't necessarily mean no problem. No chlorine consumption at shock levels is the significant data point.

2) duraleigh was (hopefully) correct when stating: "I think you are overlooking that you probably have never quite killed the algae thoroughly" This is the most thorough, SLAMing my pool has had. I have humbly dropped my "good enough" attitude regarding brushing, running the pump, checking levels throughout the day, ignoring the niche, etc.. By the book this time. No shortcuts!

Thank you all for the comments and suggestions. Will report back in a month...

 

[foobert]

Re: How aggressive is mustard algae

2 nights ago I was unable to hold mustard SLAM FC levels throughout the night (lost 1.5 ppm). I wasn't able to tend to it during the day time due to work. So, I hit it again for one more night and lost 1 PPM when I checked it this AM. I suspect all the brushing is still finding some bits of black algae hiding in the rough edges of the plaster flakes.

I'll call that a pass and with a cumulative of >24 hours at or very near mustard levels.

15.3 gallons of 12.5% bleach in total for the SLAM processes.

Curious to see where the PH has gone in this process. It'll be mid-day tomorrow before the FC falls below 10 to reliably check.

 

[duraleigh]

Re: How aggressive is mustard algae

I think you will find your pH has hardly moved.

 

[foobert]

It's been almost a month -- no sign of mustard algae recurring.

I wasn't making any headway wire brushing the black algae rings in the ridges where the plaster had flaked. A week ago, I broke down and bought some trichlor pucks and methodically scrubbed the voids with them.

I'll be darned that almost every one of the black rings have completely disappeared. I'm down to just a few spots that need a second puck treatment.