Helping out a neighbor - mustard algae?

[ship of fools]

I'm trying to help out a neighbor who has been struggling with his pool and what he believes / has been told is mustard algae. This was a problem all of last year and again this year. He has a gunite pool with one light and a ladder. When we tested we came up with cya of a little over 100 (between 50 and 60 when diluted 50/50 with tap water), chlorine of 0, cc of less than .5, calcium was 220 or so, ph of 7.5 and ta of 60 or so. Water is clear with no signs of green algae. Here is a picture of the suspected mustard algae

which comes back after vacuuming to waste. Short term action has been to vacuum to waste and refill with clean water to lower cya a bit while he waited for his own test kit. I'm going back to help in the morning and looking for some input as i have never dealt with mustard algae and have read it is often misdiagnosed. I know we need to get the cya down and slam but any other thoughts?

He has been using pucks but will be going with liquid chlorine now.

Thanks!

 

[ship of fools]

Also the ladder is out of the pool.

 

[Casey]

The pool needs SLAM'ed. Once the SLAM has been completed, a daily dose of chlorine will keep the green monster away.

 

[ship of fools]

No green at all .... Just the yellow

 

[Casey]

No green at all .... Just the yellow

If it's algae, chlorine will kill it. The chlorine must be maintained to be effective.

 

[jmiller81]

Hey, I'm having the same problem, except mine turned out to be pollen from flowering nearby trees. I slammed for about four days and vacuumed, back washed to waste and refilled. Water is super clear except this **** on the bottom of the pool floor that comes back no matter what. Finally, this morning we realized it was pollen that was settling on the pool bottom. I can vacuum it up after it has settled a bit but comes back each night. I actually bleached the bottom of my newly painted gunnite pool by slamming so hard for days.

 

[ship of fools]

Quick update after this morning. CYA is down to 70 after a partial drain and refill. The accumulation of material on the steps (in bright, sunlit area) felt like sand to me. He had a pool guy replace the sand and he thought the laterals as well last year. The pool is crystal clear except for this stuff. He is going to do the oclt tonight. Any thoughts on identifying it as mustard algae versus sand?

 

[cfherrman]

I believe you can add de to the skimmer and watch the returns for de to come out if your filter is not working right

 

[Casey]

Quick update after this morning. CYA is down to 70 after a partial drain and refill. The accumulation of material on the steps (in bright, sunlit area) felt like sand to me. He had a pool guy replace the sand and he thought the laterals as well last year. The pool is crystal clear except for this stuff. He is going to do the oclt tonight. Any thoughts on identifying it as mustard algae versus sand?

The pool will fail the OCLT if it's algae.

 

[JamesW]

Put a skimmer sock or knee-hi stocking in the skimmer basket and then vacuum with a vac plate over the skimmer to catch the material for examination.

 

[ship of fools]

The pool will fail the OCLT if it's algae.

So here's where it stands. Last night the FC reading was 40 and the CC was 4. This morning the FC was 39.5 and the CC was 1.5 so it appears there is algae present. We are going to keep it at SLAM level.

Is it odd that it passed the OCLT but the CC decreased?