Help!!!Long thick streak on pool floor surface & worm stains??


New member
Jul 25, 2019
Newtown, CT
First photo—Does anyone have any input on what this long streak could be from? Does it look like a stain or potentially some kind of permanent mark on our pool floor? I tried brushing but no improvement.... I’m also wondering if anyone has seen a robot pool cleaner cause any damage that looks like this..

Second photo— does this look like a worm stain? I tried to brush but nothing changed and we have 4 or 5 spots that look like this... what do you think it is and what can I do to clean it? Thanks so much!



Mod Squad
LifeTime Supporter
Jul 10, 2012
Tallahassee, FL
Hi and welcome!! In the first pic I can't really see what you are talking about it. On the second one it does look like a worm stain or such. I have a link for you to read. It will give you some ideas to try to see how to fix the second one.

Now for the first one you will need to some work. You NEED to get a good test kit. Here is a link to show you the different kits: Test Kits Compared - Trouble Free Pool Me? I think the TF-100 is the best bang for the buck. Look in my siggy for where to get it from.

Next here is some homework for you. I some links to help you learn about caring for your pool on your own. It is cheaper and your pool will look better once you take over it's care using your own test kit.

Let us know how the stain testing goes!



Gold Supporter
May 16, 2010
Chapel Hill, NC
"Worm" stains like that (and similar brown leaf stains) usually go away if your chlorine is high enough. Try putting a chlorine puck on it for a few minute and see if it goes away.