Green again, 3rd SLAM this year, advice please!

[DirtyRat91]

Well poo. I started the season excited about the TFP method. SLAMed early, blamed that on a rough opening session which sent some gnarly tarp water into the pool. Round July 4th I got a similar cycle of yellow gunk accumulating on the floor to wall slopes. Did a quasi sand filter rebuild with a new lateral/standpipe assembly. SLAMed again as filter was down for a few days and it went rather green again, despite keeping FC level's up.

About a week ago the same ole yellow crud started growing on the wall slopes again. Friday it was less that the crystal clear it typically is, and today it is a very light green again. Despite keeping a minimum of 5.0 FC in the pool since the last SLAM. One day I saw 4.5, but that was the lowest it ever got during the span. CYA is less than 50. Normally tests around 45.

Here's what we have going on:

Pool cover, which cruds up quickly. The reel side edge collects grime, and from this picture the top right corner likes to collect grime, shown in the next photo. This cover stays on all the time, only coming off for the occasional swim. Less frequent this year as the sun has decided to stay behind the clouds most days. What a cool summer.

I wonder if this isn't a large cause of my woes. This grime collects on the cover in this one corner, and along the reel edge. Seems like sawdust, but not sure why it collects so regularly. I pinch it off the best I can before removing the cover, which leaves a brownish water there on top of the cover. I fear this cover is a large cause of my repeat issues. I complain to my wife, 'I leave the cover on, we have a warm dirty pool. I leave the cover off, we have a cold clean pool.' It obviously renders the skimmer useless.

Not sure of its relevance, but this dirt looking stuff often accumulates in the stair dimples.

I have a hard time snapping shots into the pool during the day. My camera lacks a viewfinder, the LCD is useless in the (overcast) sunlight, but this picture gives the idea. (Forgive my awesome 49ers flops in the photo, and my unsightly toes) About 8 inches from the wall, the flat floor angles up 45 degrees to the wall, about 8" off the floor. This angle slope is where the yellow dust grows, just prior to cloudy, then light green pool. I call it dust because the slightest water turbulence causes it to cloud into the water. Extremely effortless brushing clears the slopes. Even got a light coat on the whole floor now.

Current numbers:
7.6 PH
5.5 FC
~45 CYA
120 TA
225 CH

Hit it with about a quarter jug of MA about a half hour ago. Going to hit it hard with 12.5% bleach now.

 

[MBG75]

I would say the cover needs to be laid out and scrubbed down with bleach.

As for the pool, my guess is at some point it dropped below your minimum FC level.

Bring it back up to SLAM level until it passes all 3 criteria.

 

[YippeeSkippy]

How are you testing, and are you actually completing a full SLAM process before calling it quits or just tossing in something you call "shock"? Have you checked for occult algae behind the light or in the stairs/ladder?

 

[jamis]

Next door neighbor once had a contaminated solar cover. Every time he'd put it on, he'd get algae in the pool. He took the lazy way out and simply replaced the cover. When I went through a SLAM last month, I put the cover on and put everything (toys, tools, floats, etc) in the pool under the cover. When I removed things after 24 hours, they all got a through scrubbing including both sides of the cover.

 

[DirtyRat91]

I would say the cover needs to be laid out and scrubbed down with bleach.

As for the pool, my guess is at some point it dropped below your minimum FC level.

Bring it back up to SLAM level until it passes all 3 criteria.

Since the last SLAM, I've been rather anal about keeping the FC higher than I had, I keep it consistently around 6. It dips to 5, or typically 5.5 by the end of the day, and I bump it in the evening to 6.5 so that it has a higher FC level for a longer time during a 24 hour cycle. I've also set the pump to run almost all day long, pump sleeps when I do. My fear was that the sunlight was causing certain areas of the pool's FC to drop, so the nonstop pump keeps it all circulating. I had lower pump run time during daylight hours, but a few dips in the pool and I found some HOT spots in the pool. I theorized that these hot spots could be lower FC spots too. Probably just silly talk.

How are you testing, and are you actually completing a full SLAM process before calling it quits or just tossing in something you call "shock"? Have you checked for occult algae behind the light or in the stairs/ladder?

Testing with a TF-100 kit. Shocking with 12.5% bleach. About 2 gallons gets me up to 20 FC. Last SLAM ended after I had a clear pool, 1 FC loss overnight, and 0 CC. The final evening I jacked it up to 23 FC, and wound up with about 22 FC in the morning. Pool looked amazingly clear then, and stayed that way for a week or two. I was able to see 'through' the pool for the first time. That is, with goggles on, I could sit at one end of the pool and see the detail of the vinyl on the opposite end of the pool, 32' away.

Also, no ladder in the pool. Stairs are molded plastic. I did hop in early today and went nuts with the brush, on one of the seams of the stairs (where the vinyl meets up to it) I got a gnarly black cloud. I'll admit I've never went after those crevices before, and not sure what the black cloud meant, but hit it again and got nothing. Pool's been at 20 FC this afternoon, I'll check it again and reset to 20 now.