Mustard Algae?

[beefchips]

Ok, bought this house this summer and pool was maintained by a pool company. Everything was good to go when I let them go. I decided to take over and save some money while at the same time learning the chem of my pool. Started off by taking my water samples to pinch a penny etc... They seemed fine and my readings have been pretty normal. Add a little chlorine here, little acid there.

Everything was fine until about a week and a half ago. Started noticing a fine layer of reddish dust on the bottom of the pool and halfway up the walls. Brushed them and it came right off no problem. Ordered my own Taylor 2006 TK which came a few days ago. It's slowly gotten worse over the last week or so and now the water is pretty cloudy and the dust is everywhere. I just vacuumed the whole pool floor yesterday and tonight I can see it's back. Cleaned the filter after vacuuming last night and it was fairly dirty (I just cleaned it on Saturday)After doing some reading it sounds exactly like mustard algae.

I don't think it's really bad right now, but I don't want it to get bad. I'm thinking I need to shock the thing (I had it up to 10ppm last Friday after cleaning my lanai to be safe). Here are my readings from an hour ago:

FC: 2.5 ppm (this is down from 10 on Saturday morning, though the 10 was measured at the pool store)
CC: 0.5 ppm
PH: 8.0 (I just added 3 cups of acid to bring it down after taking this reading)
Alk: 80
CH: 290
CYA: 55

So which way do I go here? How high should I bring the FC? Does it sound like algae? (Oh, FYI, the pool is inside a screened in lanai and there's no pollen or anything kicking right now. Don't think it's that).

I've got a Sta-Rite PLM 150 filter system BTW. Not sure it's in my sig. Also 13000 gal, IG, plaster, bean shaped, 4 ft shallow 6ft deep.

 

[danacc]

When you say it "sounds exactly like mustard algae", could you describe what you are seeing that matches mustard algae behavior/characteristics?

I would start with the assumption that you have plain ole algae and SLAM: http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl. Once you're done with the SLAM, chances are good that it won't come back. If it comes right back, then you can do a quick SLAM followed by mustard algae-killing FC levels.

 

[beefchips]

Very thin layer of dust all over the bottom of the pool. It can be vaccumed up but then it reappears the next day.

 

[danacc]

Any kind of algae will cause what looks like a layer of dust. It is probably dead algae that is falling to the bottom after you increase the FC. Without SLAMming, it's not completely dying off, so it grows in the water, then more dies and falls when you add chlorine again. Since it's reddish, it isn't likely to be mustard algae (which is good news!)

Start SLAMming and keep us posted.

 

[Abigail K]

Welcome to TFP!

I would advise you to address your pH first, and then start SLAM.

Also, I would advise you to read the articles in Pool School, in particular ABCs of pool water chemistry and how to chlorinate your pool.