white foam like stuff on surface when pump is on......

I am currently working on my CYA numbers before I carry out working up to shock FC. My CYA is about 90 now and will be turning a lot more water over in the next day. I have found that when my pump is running a get a white like residue on the surface. Not sure what this could be from. It could just be the water or stuff dieing and ending up on the top. I had to replace one of my filter grids when i opened it up last which was last week. One of the grids support that locks into the manifold was broken and letting DE thue. to the returns, not much but some. Could this white stuff be still something from the filter? Pics below now. Thanks in advance



LifeTime Supporter
Feb 8, 2009
New Jersey shore
looks like too much 10% algaecide to me. Did you or someone add algaecide at the pool opening? Just let the filter run it will burn off within a week


LifeTime Supporter
Apr 2, 2008
Acton Maine
Oxidation process, cya of 90 is high are you dumping and replacing water to get it down? Once that is done, just shock it, it will go away, happened to me to, did it for a week then just stopped on its own.
yeah sadly leslie's had me put green to clean and that first aid stuff in while I was in the first stage of shocking. Well per there shocking instructions. There was just too much junk in the pool so most of the chem were used on killing it as I was getting it all out. My main worry was that it was a DE residue, since I had a grid leaking and didn't want to keep running the pump if there was a leak still. Yes I am draining my pool as we speak to get the CYA down. Another get tip from them, Shock with granulated chlorine. Granulated chlorine raises CYA. I found out later after using about 20 pounds. Oh well you live and learn. Now I found this site, I know it will take some work but it will get there. Thanks again guys for the info


LifeTime Supporter
Aug 20, 2009
North Central Texas
DE usually sinks pretty fast and will end up on the bottom in a short time unless the bottom is constantly stirred up. When I've had to clean up DE I let it settle out then slowly, very slowly, very carefully, manual vacuum, then backwash. You might have to do it in several sessions as it is pretty hard to keep from stirring up a bit no matter how "experienced" you are at vacuuming DE.

No I am not running a salt set up. I thought about it but don't want to put the money up for it. lol I found the foam has gone away after I got my leak fixed. Got to love a bad o-ring in the return tube. It was probably not filtering out the stuff they had me put in. Yeah now i have a good amount of DE on the bottom. I have been working at it for a couple of days now. I have been sweeping it towards the skimmer and letting it suck most of it in. I will do a major vac job once the pool clears fully up.


New member
Jun 17, 2010
I had this same problem this year. The foam on top of the pool was so thick it looked like a latte in the beginning. I believe it was caused by the algecide added at opening. anyway, the process to clear the pool was to vacuum to waste several times (avoid having debris go back into filter). replacing water each time you vacuum. i ended up replacing about 1 foot of water in the pool over a week. i also had a problem with free chlorine. my test kit showed good chlorine levels but when i took in water sample the amount of free chlorine was low. i ended up adding about 12-14 gallons of chlorine to the pool over a weeks period of time (20K gallon pool). i'd also ck ph as mine was low. when i finally got ph up to level, the water cleared up all cloudiness and is now crystal clear.

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