No water flow when filtering, but filter shows a pressure, Recirculation works fine

Mandrake · May 28, 2016

Hi,

My filter does not seem to work. When I turn it on, after an hour or so there is no water flow, even though filter pressure did not increase. The pump is running fine when I am in circulation mode.
I got new grids last summer, and acid cleaned them last weekend, after which I put 10 coffee cups of Aquapearl. That did not seem to help, so I backwashed a little bit which seem to improve flow for a while, but then I got the same problem again, so I cleaned the filter on Tuesday, and this time used DE.

Same problem again. I checked the impeller (no clog), and cleaned the skimmer, but to no avail. I shocked the pool three times in the past couple of weeks, so my water is blue and I can see the bottom, but it is somewhat cloudy. When I run the robot, the dust comes up. so I know it'snot clean.

Any suggestion what to try?

Thanks,

M.

cowboycasey · May 28, 2016

Welcome to TFP

You have found the great part of a DE filter, they work really really well, and that is also the problem.. you probably have algae in your pool that your filter is cleaning..

What test kit are you using and what are your numbers, please post them so we can see what is going on..

My suggestion is to get a great test kit so you know exactly what is going on with your pool, check out the links below in my signature below

I hope this helps

duraleigh · May 28, 2016

If the motor is running but you have little or no flow out the returns, you have a blockage that could be in many places.

What is the clean pressure when you put the filter cartridges back into the filter?

Does your gauge go to zero when you shut the pump off.

More questions but this will be an easy fix.

As cowboy casey says, we need all your current test numbers so we have a baseline.

Mandrake · May 31, 2016

Thank you both for your reply. I am new to TFP, so I had trouble finding my own post

Anyway, my numbers are pretty good, Ph = 7.6, Alkalinity around 100, chlorine around 2.

On Saturday, I opened my filter and to my surprise (I backwashed it three days earlier), it was already very dirty. So I cleaned it grid by grid, assembled again, vacuumed the pool (to waste), and shocked.

I put slightly less DE then called for (around 80-85%), and the filter was on 13 when I ran at 2500 rpm. By yesterday my pool was crystal clear

, with a small catch. There is some white residue on the floor of the pool. I vacuumed some of it, but there is still some left. My robot is picking it up to, and I am worried that it could be DE sand (dont want my kids to swim in it).

Is there any way to verify whether it is DE indeed or just dust? If it is a leak, what would be the culprit?

M.

jblizzle · May 31, 2016

What are you testing with? What is your CYA? I suspect your FC is too low for your CYA level and you have algae clogging up your filter.

Mandrake · May 31, 2016

I am testing with Taylor test kit. My CYA is pretty low (10-20, can't really measure it precisely), and as I said my pool water is crystal clear now.
My current problem is a white dust at the bottom of the poolwhich I suspect is DE.

jblizzle · May 31, 2016

What Taylor kit?

Dust could be dead algae.

Have you torn down the DE filter and inspected everything?

Mandrake · Jun 2, 2016

I am using Taylor K-2006 Complete (FAS-DPD chlorine).
As for white powder, I vacuumed it and it did not come back, so I am holding inspecting the grids again (I did it a week ago) until the powder comes back.