Algae - again?

[MITBeta]

I noticed lots of greenish-brown "dirt" at the bottom again today after vacuuming last night. Dove down the investigate - "poofs" away when I touch it. Thinking it's algae, again, after completing a SLAM 2 weeks ago (met all 3 exit criteria) and battling algae (realized in retrospect) all last year.

Brushed pool, including skimmer throat. Removed ladder and mat.

Added 700ml muriatic acid to lower pH before slam.

Added 2lbs. 65% cal-hypo (had it on hand, vinyl liner, 190 CH). Pool Math says this will add 11.8ppm. SLAM target is 16 @ 40ppm CYA.

Effect of cal-hypo was 14ppm rise 30 minutes after adding to FC of 19.

I have no lights or other nooks for algae to hide.

My question: what do I do with the ladder? During my last SLAM I tied it to the side of the pool so that it was completely submerged and the pipes were completely full. I drained and refilled the tubes several times per day. This time I noticed that each step has a cavity in it that likely doesn't see fresh, chlorinated water very often.

Do I leave it out? How long can algae live out of the water?

Do I completely disassemble and submerge each piece? I would have to cross my fingers it goes back together properly. Pictures attached.

 

[Wobblerlorri]

I would take it out and scrub it with bleach water. Pressure wash it, too. Blast out all the little books and crannies where algae likes to hide, then lay it out in he sun.

 

[Richard320]

I wouldn't be so quick to blame the ladder. There's algae spores blowing in and getting tracked in constantly. I'd blame low chlorine.

Either you let the chlorine get too low or the CYA is higher than you think or it's localized low because of poor circulation and lack of brushing.

 

[MITBeta]

You can see from my logs that FC has not been lower than 4.0ppm since my SLAM ended, which is above the minimum for 40ppm CYA. I run my pump almost all the time on low speed. I take my samples well away from the return.

The only thing left is CYA. I have run this test multiple times: prepare sample, fill to 60, stand with back to sun, hold tube at waist level and glance. It always comes out between 30-40. Test kit is a month old.

 

[Richard320]

You can see from my logs that FC has not been lower than 4.0ppm since my SLAM ended, which is above the minimum for 40ppm CYA. I run my pump almost all the time on low speed. I take my samples well away from the return.

The only thing left is CYA. I have run this test multiple times: prepare sample, fill to 60, stand with back to sun, hold tube at waist level and glance. It always comes out between 30-40. Test kit is a month old.

How much brushing have you done since the slam finished?

 

[MITBeta]

Admittedly, not much. I didn't even have the right brush until a few days ago. The bottom gets brushed 2-3 a week with vacuuming, but the sides have only been brushed a couple of times in total.

How often should I be doing that during SLAM and during normal maintenance?

What should I do about my ladder? I don't have a pressure washer.

 

[MITBeta]

Overnight I lost 2.5ppm FC. There is a small bit of dead algae all over the bottom, which I'll be vacuuming as soon as I get a break from work today. Pictures attached for reference.

 

[Richard320]

If you follow the SLAM Process instructions, you Brush and vacuum the entire pool once a day

When it's clean and you're just following Basic Pool Care Schedule - Trouble Free Pool Brush and/or vacuum the entire pool or run pool cleaner.

The ladder? Get in there with a bottle brush and get any visible gunk out and let things soak in the pool while it's at slam level. Then reassemble it.

 

[MITBeta]

Ok. I have disassembled the ladder and the steps are floating around in the SLAM level pool (tried to get as much air out as possible) . My wife tied a scouring sponge to a rope and ran it through each pipe. The pipes are now laying on the bottom of the pool, pointed into the direction of the circulating water.

I'll pulled everything out and re-scrub in a while.

I have lost very little chlorine today, despite direct sunlight. Have held 15.5ppm all morning (SLAM level = 16).

 

[MITBeta]

Any further thoughts on how I developed a new algae outbreak despite keeping my FC above minimum for 50 CYA even though I have consistently measured between 30 and 40 and have mostly targeted a minimum of 5ppm?

Is it just because I missed one weekly brushing?

 

[Wobblerlorri]

You've got hidden algae somewhere. In the ladder, under the ladder mat if you use one, in a pool float or toy, there's no telling. If it was an IG pool, I'd say look in your light niches, in ladders, on ropes.

 

[MITBeta]

If anyone is still following this post:

Still SLAMming. Had 1.5ppm drop overnight with dead algae on the bottom again this morning. Vacuumed on my lunch break and will brush later this afternoon. Have scrubbed the ladder steps and will "floss" the inside of the ladder poles again, too.

I did find something interesting while testing FC yesterday afternoon: I took a sample from the normal spot and FC was much lower than I expected - 13.5 vs 15ish. Took another sample from near the return and it was 15.5.

Obviously, I was not getting good circulation with the pump on low speed. If I direct the return eye to the side to create counter-clockwise circulation, the water all seems to move (confirm with rope tell-tales), but skimming suffers. Direct the eye straighter out into the pool and skimming improves at the expense of circulation.

So I have to pay more attention to this going forward.

 

[MITBeta]

Passed OCLT last night, but a small amount of algae was still visible in the pool again this morning. So SLAM continues.

My algae must be coming from my ladder. I have stains on the inside of stairs where the pole goes through, but can't tell if this is algae or something else. I scrubbed the stains several times yesterday and currently have them in a high bleach percent bath to see if the staining goes away.

Plan B is a new ladder.