Brownish red spots on floor of pool

[DPS072124]

Hi all, I am 7 days into a SLAM but haven't identified the problem brownish red spots on the floor of my pool, which brush off easily. I thought originally that it was a bacterium (red slime algae) but it didn't seem to follow everything that I read about it (wasn't on the walls, steps, return or skimmer, just the floor). I did have a single spot show up on the pool wall recently and it felt puffy, a little slimy and possibly had some grit which probably isn't possible. It reminds me of a soft crayon. These spots are quarter size or smaller usually and some are thin lines, so I haven't been able to take a decent picture. When using LC the coloring doesn't change. When I used Cal Hypo (Still had some and the CH is low) the color changes to a gray and after continuing to brush, they will continue to return getting darker over a couple days. I pulled my steps out and left them on the deck for a few days and when I took them apart, they had pink inside (Could this be the answer?). Before I started the SLAM I drained 1/3 and then 1/4 of the water to lower the CYA. The O-ring on my filter failed and it didn't run for those 2 days, amazingly I never saw a spot appear those days. I wasn't sure if adding public utility fill water had something to do with that but when I started running the filter the spots were back. I've played with the circulation, and the spot locations move. I'm new to testing and my most recent tests are FC = 18.5, CC = 0.5, PH = 7.4, TA = 80, CYA = 40, CH = 175. Also, I haven't been able to pass an OCLT and I put a new cartridge in the filter. It doesn't seem to be pollen (low spots aren't filling) and I'm wondering if it's a Brown / Mustard Algae? My SLAM doesn't seem to be progressing, and Pool Owner Patience is running thin. Thanks in advance for your help/guidance.

 

[ajw22]

Welcome to TFP.

In looking at your PoolMath logs you are losing less then 2ppm/day.

See if your pool passes the Overnight Chlorine Loss Test

Run your pool at SLAM FC level when not swimming in it and let it drop a bit below when you want to swim in it. That should take little additional effort and you can be using the pool.

I don't think those brown spots are algae. All sort of other stuff can blow into a pool. Let your pool cleaner clean it up.

 

[DPS072124]

Thank you for the reply AJW22, that’s surely a better plan than what was going through my head lol. Unfortunately the pool cleaner is me currently, but it sounds like I should start looking through the TFP threads for what people think is a good automatic cleaner for an AGP. Thanks again, Don

 

[DPS072124]

Final thoughts and a few lessons learned from my first SLAM. SLAM seems to have worked beautifully. It took 2 full weeks but part of that was probably my own fault. I didn’t realize that the OCLT wasn’t dusk to dawn. Found a thread that identifies 30 min after dusk and 30 min before dawn. That seemed to work better for me. I also found a thread that mentioned to use a heaping teaspoon of the R-0870 DPD powder for FC test. I think I was using enough and it wasn’t a problem but I use more now to make sure. Lastly even if you think you’ve cleaned and brushed everything, think again. After AJW22 responded On August 8th 2024 I was still not passing OCLT. Seems simple right, It’s a round pool (steps were out) with no corners, so I really worked on the skimmer and return thinking that had to be it. Nope, when I paid closer attention to where the walls meet the floor, bingo! There was a noticeable usage of chlorine and the filter pressure went up overnight. I then passed the 3 tests to complete the SLAM. Thanks everyone at TFP and I hope this recap helps someone else in the future. This should complete my thread. Don