SLAM in one day?!?


May 28, 2017
I live in the deep south. Our winters almost never get down into the 30s, so I'm used to opening the pool to a green soupy mess every year. This year was no different. Usually the process of cleaning and SLAMming the pool takes four to six days of constant chlorinating and cleaning, but this year the water is almost entirely clear (I can still see a bit of slight milkiness to it, but I expect it to be gone today) and I had no FC loss overnight after just one full day of SLAMming. Is that possible?

I set up the plumbing and filled the pool on Monday. Took off the cover on Tuesday and started everything up. With the pump running, I balanced CYA and pH and tested TA and CH. Early Wednesday morning (yesterday), I vacuumed the gunk out of the pool and started to SLAM. In the first hour, I lost 2ppm FC and raised it. Over the next four hours I lost 2ppm FC and raised it. During this time I also brushed the entire pool and vacuumed some more stuff that had settled on the bottom. The green was almost gone. Then, overnight, about 10 hours, I lost no FC (still at 12ppm), and water is almost completely clear.

What happened yesterday, usually takes me four to six days. I'm going to keep SLAMming until the water is completely clear, and I know It will take a few days until the FC goes down enough to put the kids in the pool. Regardless, I'm not going to let them in the water until I can get a reliable reading on the CYA (probably Saturday). Am I just the luckiest man in the world right now, or am I missing something?

My stuff:
- 16kgal above ground - vinyl liner
- FC - 12ppm (right now - 0 at opening of course)
- CYA - 20-30ppm (It was 0 at opening, and I added enough CYA to bring it to 30ppm, but we had some rain and I had to drain some water from the pool. I'll start testing tomorrow—day 3—to see what my CYA levels are.)
- pH - ~7.4 (It was a bit below 7.2 at opening so I added enough "pH Up" to raise it to 7.4 because I knew we were expecting some rain. Once the FC levels go down, I'll test and balance again if necessary.)
- CH - 50ppm (I usually don't even bother testing this, but since I had to use CalHypo this year because bleach was nowhere to be found on our shelves, I'm testing for it now.)
- TA - 40ppm (I know this is a bit low, but it usually runs low without a problem. I'll get some baking soda this weekend to raise just a bit.)
Last edited:


Gold Supporter
Bronze Supporter
Jun 11, 2018
Verona, MO
Lucky dog! :)

The "almost" completely clear is only concern I see.

Keeping FC on the high side for your CYA level probably a good idea though for few days, just for comfort sake.


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
You had it covered, so no huge piles of soggy compost. It wasn't full all the way so you diluted the green when you added water.

You started with minimal problems, did things right, and got lucky. Don't jinx yourself by questioning it!


May 28, 2017

I did a very precise overnight test (tested, raised to shock level, tested again after sunset, and then tested again before sunrise), and there was about a 1PPM loss of FC, within the margin of error for the test. :D I'll give everything a good brushing, vacuuming, and SLAM for one more day (we're supposed to get a lot of rain today anyway), but I think we're done.