FC level 18 with no chlorine added- possible causes?

[PoolGuyNJ]

I take it there are 3 Mushroom distribution gear boxes?

If the VS is running full tilt, it isn't a lack of flow unless they undersized the filter. It's possible the nozzles in the in-floor heads are too large.

How many heads pop up at one time for each zone?

There are pressure gauges on each of the mushrooms. What is their running pressure?

What is the pressure on the filter?

Do you have a debris catcher too?

 

[jennacarly]

I don't know what a mushroom distribution gear box is. They came back and we increased the pump to run at full speed, bypassed the filter to see what kind of pressure we could get and the two pressure gauges near the ground said 15. They told me that was the minimum needed for the cleaner to run effectively. We backwashed the filter and have the cleaner running at top speed but I am still getting piles of sand which do not clear. They said it was due to the pump not providing adequate pressure. What do you think?

Yes, there is a leaf catcher as well. The filter pressure reads above 30 when it is running at full speed, in the 20s when at "filtering" speed.

Thanks so much for your thoughtful input!