Ok, towards the end of summer we had a problem with reoccurring algea bloom, not bad but it would keep hitting us about every two weeks. Finding patches on the bottom, water not sparkly, we could not figure it out. Followed overnight tests, shocking to match or just above, brushing, vacuuming to waste, scrubbing light and ladder, over under and in the middle. Well brought it back to shock again, cloudy water, no overnight loss for two nights. I had enough. Then I remembered the weep holes in the ladder that I filled with pool water to submerge it when I built the pool. Tiny holes on each step, it's a Confer heavy duty. Ahh, maybe since I cannot see anyway that that water could circulate through those steps. Pulled it out and as the water drained lime green koolaid came out of each steps weep hole especially the bottom one. So instead of a tiny hole I drilled them 1/2 size to allow more water to get into the steps when I put it back in. I also flushed out each step which had green water coming out the holes. I took my meat syringe, Clorox, and pumped it into each hole, (note to self, syringe Clorox in the holes at least once a month). Now I believe this was the culprit that kept me from clearing the algae, but time will tell. I do keep my numbers inline making sure my FC is equal to the CYA chart and regulated it faithfully following the experts here. Hopefully this may shed some light to other people with these submersible ladders or steps, and I live in south Louisiana, where our humidity and summer rains gives us pool owners nightmares with algae.