Small amount of algae constantly growing on walls

Apr 30, 2017
38
San Jose, CA
Pool Size
24000
Surface
Plaster
Chlorine
Liquid Chlorine
Hi,

I've been following the ABCs for a while now and my numbers are all within range as far as I can tell yet when I brush at times, I still see a small layer of green algae being peeled off of the walls. I SLAM my pool and brush it heavily and despite being within range, algae still seems to grow on the walls. It's not crazy bad. When I brush it, the water becomes a little murky, but after 2-4hrs of filter running, it typically comes back to clear without adding more chlorine, but it seems suspicious still.

I SLAM'ed my pool 2 weekends ago ( and just SLAM'ed it last night)
FC: 14 due to SLAMing (typically around 4-5 but can drop as low as 2-3 right before it gets additional chlorine during the day at 8pm)
pH: 7.4
CYA: 30
Alkalinity: 90
CH: 390
water temp: 77F
Uncovered
robot runs : every 1-2 days.

I tend to add 2ppm of liquid chlorine daily to maintain the right levels. I brush it every 2 days.

I somewhat regret having pebble tech in the pool as I feel like the little pebbles tend to harbor and hide some of the algae (ie: creates opportunities for it to hide on the walls). I wish we had gone the route of polishing the surface and making it nice and straight instead of roughed like it is now and wonder if that's not contributing to it at some level.

Any idea what could be going on here? I'd be happy to share the daily results (ie: right before chlorination) for the rest of the week if that helps paint a more accurate picture.
 
You ignored the M in SLAM. I'm not sure your wrong about pebble finish being a potential problem. I'm sure it causes faster wear on the brushes of my robot. Less slippery for little feet, though.
 
You ignored the M in SLAM. I'm not sure your wrong about pebble finish being a potential problem. I'm sure it causes faster wear on the brushes of my robot. Less slippery for little feet, though.

Yah given the choice, I would definitely polish it or go with quartz. It's certainly true for the robot however. But by the same stance, the robotic cleaner also tends to tear off little pebbles (at least it used to once we first got it done). Not so much anymore after 12 years.

You cannot follow the SLAM Process in a night.

You follow the SLAM Process until you pass the three exit criteria and the water is algae free.
I meant that I 'started' the process last night. It's still running through today and yes best case scenario, I'm 'done' with it tomorrow morning after I've verified the levels since it's been clear throughout.
 
every time your FC drops to 2 algae can start growing... For your area I would do a couple things..

1. kick CYA to 40 at least..
2. never ever ever let FC get to the minimum.. min is a cliff, you do not want to drive off a cliff, you really do not want to be near a cliff... keep the lowest FC level at the target level, so for CYA of 30 the lowest you want is 3 FC..

With a CYA of 40 target 5 to 7 FC but keep it above 4 at all times.. if you have to raise FC to 8 that is better than going to min... :)
 
every time your FC drops to 2 algae can start growing... For your area I would do a couple things..

1. kick CYA to 40 at least..
2. never ever ever let FC get to the minimum.. min is a cliff, you do not want to drive off a cliff, you really do not want to be near a cliff... keep the lowest FC level at the target level, so for CYA of 30 the lowest you want is 3 FC..

With a CYA of 40 target 5 to 7 FC but keep it above 4 at all times.. if you have to raise FC to 8 that is better than going to min... :)
Yah raising the CYA probably does make sense here. Thanks. I think I'll give that a try.
 
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