low speed filtering and scrubbing

[Diver]

I’m on a 3rd season of my pool ownership. The first season I had a single speed pump and it was uneventful. The pool was pristinely clean, once a week I would use a robot-cleaner to clean the pool and that was it. I switched to slow speed filtering on my 2nd year.

This current season I had a problem with solar cover and after I got rid of it everything seemed to be fine, except few green spots on the liner. The chemistry is spot on and a friendly push with a brush would get rid of the green spots. The spots seemed to be powdery – I didn’t actually had to brush it, I could simply push some water towards them and they would disappear with a poof..

I contemplated the idea that it could’ve been the pollen, but I’m pretty sure it’s algae.

Aside from very light brushing every day or every other day, everything seemed to be fine.

My understanding is that with change from normal speed to slow speed filtering I lost some of the circulation that now allows for some spotty algae growth. I used to filter 5-6 hours on high and now I do 10-12 hours on low. So the turnaround is about the same, but the exist velocity for jest is lower.

My question is – is a normal routine for low speed filtering? I think some people brush all the time, but I didn't had a need for it before. I think filter time increase will not fix this, I simple have to brush here and then from now on.

 

[Bama Rambler]

Have you ran an OCLT to see if it was organics? If you haven't, you should.

Maybe you need to change the eyeballs or just re-aim them to get better circulation. Running the robot should also help.

Can you post a full set of test results?

 

[Diver]

Bama Ramber,

That was a quick response. The pool is closed right now, but as I mentioned the chemistry was in check. Here are the numbers that I had before I closed:

CYA: ~30
FC: 4-6
CC: 0
TH: 180
PH: 7.5
TA: 100
Borates: 35

OCLT always passes. I do have eye balls with slightly large opening for better flow. I could try to use the old ones with small opening. I tried playing with eye ball direction, but it didn't seem to have a significant impact.

 

[linen]

Have you tried ping pong balls on the surface to see what circulation pattern you are getting? It might show dead spots.

You may have to go with the smaller eyeballs to get the velocity up now that you are running on low. I would try it at least.

 

[Diver]

the corners seem to be problematic for surface circulation since i see the sunk debris there, but the eye balls will not turn that far. the green spots don't seem to have a pattern that i can understand. it just seems anywhere below 4 feet is a fair game for them.

 

[Bama Rambler]

You could put a 90º elbow on a return or two and then put the eyeball in it and turn it along the wall. Maybe that would help.