Can't get rid of algae (even after SLAM)

[allendehl]

Hello folks,

I've been through SLAM 2 times in the last few months and currently undergoing my 3rd time. The first two times I believe I did it correctly and with good discipline. I only stopped after all conditions were met (clear water, less than 1ppm loss overnight and FC < 0.5) only to develop algae all over the surface of the pool just a few days later.
After completing the second round I even tried to maintain chlorine levels higher than recommended in the SLAM chart (my CYA was at 30 and I kept it on 6 or above)
Now, after a few days of keeping chlorine at 12ppm (CYA =30) last night I lost about 1.5ppm. I went into the pool and saw the green enemy growing again in the tiles grout and some of the pool surface again. I brushed off all I could but some are really really tough.

At this point I am at a loss. No idea what I could be getting wrong here or if I have any other factor causing my pool to go nuts. My filter is keeping the pressure at around 15psi, not sure if this is ok or not.

Any help would be really appreciated.

Using the TF-100 kit for testing.

 

[picchu55]

I recently went through something similar. Did a SLAM, met all the finishing criteria, then a week later had algae again. At that point, I was told I probably didn't get it all the first time, and that it was hiding behind the lights or on a ladder. Turns out, mine was hiding on the threads of the return jets. Ended up replacing mine because the old ones were completely stuck, and I've been running crystal clear ever since!

 

[Newdude]

Once you know you have a recurring problem, you need to go full bore on all the hiding spots. A member had a similar time recently and their light niche was caked inside. Another had a nasty weir door. Pull ladders and run water features, anywhere that algae can hide is suspect. The filter needs a full cleaning too. One or more are making it return so its worth the time to find it or the cycle will just keep repeating. Also when you are done this time, stay in SLAM for an extra day or two as added insurance.

 

[Mike1162]

What time of the day are you adding the chlorine? Are you testing the chlorine level before & after adding? Please add your pool/equipment info to your signature.

 

[allendehl]

Thank you all very much for your responses.
I'll keep looking. My pool doesn't have many hiding spots, it doesn't have ladders and the light fixtures are well sitting so I hope they are not holding any hidden water inside or behind them. I looked at the skimmer and don't see any nasty algae spots.
Now, there are parts where I just couldn't scrape off all the green. Some of the tile grout and even parts of the diamond brite will just not clean completely after brushing it off with a hard cell brush. I assumed that chlorine would eventually kill it and it would come off easier. Am I wrong?