FC is constant overnight but still visible algae???

[Knichols]

hello,
We've been battling algae ever since we upgraded our pool equipment. We knew we might have some minor problems because the pump was off for several days while we plumbed a new pump, sand filter, and liquid chlorinator.
Sure enough, we had a little bit of green on the bottom of the pool. If you swipe the brush across it, it disappeared. So it must be algae, right? So we shocked the pool. Repeatedly. We've done regular shock and are currently at yellow mustard shock levels. No impact to the algae.
Here's the kicker. I'm not losing ANY chlorine overnight! And Ive never had ANY combined chlorine, day or night. Not even 0.5. I brush the pool everyday, and now, I have enough algae that it is gathering in small clumps at the bottom of the pool. We've been at it all season, but it just keeps getting worse!
The algae kicks up a cloud of light green when I brush. It's never turned grey or brown. What am I missing?
***edit: we are at 20 ppm CYA. I intend to bring that up, but I figured I would wait until we were done shocking. We've been shocking off and on for 2-3 months now, with no success.***

 

[swoopman]

Just to be clear, are you shocking your pool or following the SLAM procedure?
Pool School - SLAM - Shock Level And Maintain

Would you post a full set of test results?

 

[chrismar]

I'm a new pool owner myself, but what about vacuuming it out (and straight to waste, if possible)?

 

[Knichols]

We are SLAMing, but the only time the FC goes down is during the day.
Fc =12
Cc= 0
Cya=20

- - - Updated - - -

I'm a new pool owner myself, but what about vacuuming it out (and straight to waste, if possible)?

We actually don't have a manual vacuum. We have a robot vacuum. So there is no option to vacuum to waste.

 

[cowboycasey]

are you using the fine , 2 micron cartridges in mr roboto

 

[Knichols]

I'm not sure. We are using the cartridges that came with the robot when we bought the house 12 months ago. So there is a good possibility that new cartridges would help. So far, we've only used him to pick up leaves and worms off the bottom of the pool. How often are you supposed to change the cartridges?

After 2 days at 12ppm, I noticed this morning that there was very little algea growing on the vinyl, but large clumps of algae laying on top of the vinyl in the lower circulation spots. (the crease where the floor slopes into the deep end, the very bottom of the deep end.) Maybe 1 sf Before, I thought that this was just a surge in algae growth, but now I'm thinking it might be dead algae, even if it is still bright green. The hubby is hoome today, so he is going to make sure that we never dip below 12ppm and run Mr. Roboto repeatedly. Maybe we are finally turning a corner...

I'm still not reading ANY CC, although last night was the first night that the FC dipped overnight (-1.5). So now I'm thinking that my DPD Reagent is bad. I'm having hubby rush order a fresh chlorine kit.

 

[msgtdan]

Maybe a dead spot in circulation? Try changing where the returns point.

 

[pabeader]

and brush all over. I mean the pool! three, four, heck as many times as you can.

maybe try to get a whirlpool going. just to get things good and stirred up.