Water Looks Perfect, but Chlorine dropping quickly

Pool Guy Jim

New member
May 23, 2025
2
Southern New Jersey
Hey Everyone,

I currently have an 18k gallon in ground pool, D.E. filter, vinyl liner and use liquid chlorine.

I opened my pool to a bit of a green, cloudy mess, but it was clear within 2 days of running the filter and using some shock.

I used my Taylor kit and chemicals to get everything balanced nicely, but the free and total chlorine just keep returning to 0. I've added 120 oz of liquid chlorine and at the end of the night recently and it was still 0 in the morning. I went through all of my usual fixes for this kinda stuff by completely cleaning my filter and grids and reapplying new D.E. I scrubbed all of the walls and kept up with larger amounts of liquid chlorine, but it only shows up for the first hour, if not less.

I brought a sample to the closest pool store and they told me it must be pollen because of our area (New Jersey), and that the chlorine was never getting a chance to survive because the pollen was using it up immediately. They recommended a weekly clarifier of sorts that helps with this specifically in addition to daily liquid chlorine doses. I believe it's called Leslie's Perfect Weekly.

I'm hear to ask if this stuff could help or if I should begin the SLAM process, even though the water looks literally perfect. No algae growth. No visible film on the surface. I'm just confused as to what is eating up the chlorine so fast.

As I mentioned, all of my chemicals are within or near ideal range except the total and free chlorine.

All chlorine is essentially near 0. Clear on taylor test tube
CYA: 50
PH: 7.4
ALK: 85
Hardness: 180 (a little low) but I'm more focused on the Chlorine right now

Thanks ahead of time.
 
Welcome to the forum!
You need to follow the SLAM Process.
What Taylor kit are using for your pool water chemistry testing?
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool
I'm using the K-2006. I'm currently going through the SLAM process and it's holding better than expected so far.

I was at 44 CYA so I added 3 gallons of liquid chlorine (10%) to reach 16 ppm. I checked about 4-5 hours later and it was still well above 10 ppm, so I only added 1 more gallon to get back to 16.

My pool was very clear before this, so I don't think the chlorine is being used up too much on visible growth, but it must be fighting something to keep dropping to 0 before I started SLAMMING.
 
Great.
It is not possible to read a 44 for CYA. Round up to 50 for your FC levels.
Maintain your 20 ppm SLAM FC level as often as possible, not less than 3-4 times per day. Brush daily.