Green Pool Help


New member
May 20, 2020
Hello! I have a brand new 26x52 Intex Ultra that I filled from our hose (town water - not well). That process took a bit more than 48 hours and completed this past Sunday morning. The water was clear during the fill up until sometime Saturday night when it turned slightly green but clear. Over the course of Sunday and Monday I brought the pool into balance using the Taylor 2006 test kit - the pool remained green and clear.

On Monday evening based on what I have been reading I began a SLAM. I scrubbed, vacuumed and began the process. My levels at that point were:

pH - 7.4
FC - 3
CYA - sub 30 but had added liquid stabilizer to get the level to 30
CH - 0
CC - <.5 (using the 10ml sample there was a slight color that went away with first drop. A previous test showed the pool at .2)

Using the Pool Math app I brought the chlorine up to 10 using 7.55% concentrated bleach.

The Intex pump and filter (not sand - the one that came with the pool 2500gph model 633T) have run pretty much non-stop since Monday evening. I put a new filter in at the start of the process and have changed it twice since. The pool remains pretty much the same color - I like to think perhaps a bit less but pictures/video over time look pretty similar. That said - the filter change yesterday morning was getting brown in the core and at the top and bottom but still had a fair amount of off-white. This morning's filter was quite brown. I also noticed late yesterday that the water coming through the two intake tubes seems to have a brown tint to it. I attached a sock to the return for a bit this morning and confirmed that it turned a bit brown as well.

I am wondering if I have an algae problem or something else. I am under an oak tree and get about 15-20 acorns per day in the pool. There has not been much sun since the pool was filled. It has rained a bit - but less than 1/4 inch I would think. I get a few leaves in the pool but not a ton.

Chlorine does not go down much if at all over night and only 1-2 ppm during the day. It was at 13.5 when I checked it at 9PM last night and was at 13 when I checked it at 5:30 this morning. All of my other test results look pretty much the same as when I started - although CYA has not quite hit 30. The black dot is almost invisible at 30 - but I need to go a bit past it for it to disappear.

I have attached some pictures of the pool, filter (and a comparison of yesterday's filter after 24 hours versus today's filter after 24 hours), intake tube and for good measure the previously white sock. I appreciate any suggestions you may have as my kids are ready to revolt if they can't go in the pool soon!

PS - Looking at the pool picture it looks a lot bluer than it does in person. I can try to get a different angle on it if that would help. Thanks!



Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Welcome to the forum!
You have iron in your water. The brown is rust that you are filtering out. Keep doing that. Do you have a skimmer? Adding paper towels or polyfill (like pillows are stuffed with) to the skimmer basket will also filter out the rust.
No real need to maintain SLAM level FC. Just use target range for your CYA.
I suggest you read ABC's of Pool Water Chemistry.


New member
May 20, 2020
I was starting to suspect something other than algae but wasn't sure what. The brown color didn't add up. Thanks for the quick advice. Is it safe to swim in with iron? I'm guessing yes but figure can't hurt to ask!