Poor flow and dirty/algae inside skimmer lines


Sep 9, 2018
One of my skimmer lines barely moves water at all unless I close off the other skimmer and main drain valves. I was thinking it was clogged and used a hose bladder to run water both directions and didn't get any debris out. However, I did determine their is a substantial amount of "mung" covering the inside of the pipe based on what was on the fish tape I snaked through the line. How do you clean the inside of a line????? suspect if may be more source of recurring algae blooms in summer.


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
I would also suggest closing off the main drain. It is not necessary for pool water chemistry maintenance. From your post, that should improve the flow through the skimmer.

You may see if you can push a hose up the skimmer line that has the 'mung'. Disturbing that biofilm and raising your FC to SLAM Process levels should get rid of it.


Well-known member
Nov 15, 2018
Perth, Western Australia
How do you clean the inside of a line?????
I've just done this. I used a bit of fluff on the end of a strong nylon "builders string" and sucked that into the pipe with the application of a vacuum hose. I let it go until I knew the fluff would be past the other end of the pipe and then dismantled to gain access. So I now had a pipe with a string through it. I tied a big bit of old cotton rag to the long end and use the builders line to pull it back and forwards through the pipe from end to end. Down here (Aus) we'd call that a "barbed wire pull-through".

In my case it's an old bottom drain in the corner that goes to a second port in the skimmer. That had a plug in it and hadn't been opened in years, and the stagnant water in that pipe was my little algae breeding ground.
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