My numbers are in range -- post-SLAM -- why is there green in my pool?

[aaroncp]

It's been 10 days since I passed the OCLT after a six-day SLAM. The water has been crystal clear and I have been testing it daily. FC has never dropped below 5. CC has been 0.0 or 0.5. All my numbers from two hours ago are below the photos. When we came out to swim today, there was a layer of green on the pool bottom, which I vacuumed away. Should I start another SLAM? Why is this algae forming if my numbers are all in range?



These pictures show the cloudiness of the water after I vacuumed this afternoon. I don't want this to get ahead of me again and become a swamp like at the beginning of the month. What should I be doing?

[COLOR=#000000]------------------------------------------[/COLOR]
[COLOR=#000000]Test Results 07-29-2018 @ 03:43 PM[/COLOR]
[COLOR=#000000]------------------------------------------[/COLOR]
[COLOR=#000000]Free Chlorine: 5.5[/COLOR]
[COLOR=#000000]Combined Chlorine: 0.5[/COLOR]
[COLOR=#000000]pH: 7.5[/COLOR]
[COLOR=#000000]Total Alkalinity: 80[/COLOR]
[COLOR=#000000]Calcium Hardness: 100[/COLOR]
[COLOR=#000000]CYA: 70[/COLOR]
[COLOR=#000000]Salt: 2860[/COLOR]
[COLOR=#000000]Temperature: 80°F[/COLOR]
[COLOR=#000000]CSI: -0.82[/COLOR]

 

[Texas Splash]

There's no mistaking the cloudiness and discoloration. Here are some items you might consider:
- When you SLAM'd before, did you remove and inspect the ladder? Those rungs/steps can hold algae easily
- Is your only return jet the one on the skimmer side? If so, lack of good water circulation to the ladder area might be a contributor
- Any chance the CYA could be higher, thereby throwing-off your required FC level?
- When you SLAM'd previously, did you also do a deep clean of the sand?

 

[aaroncp]

I just took the ladder out and there's algae there. [emoji849] Going to scrub them with bleach.

With my skimmer and return jet locations, is there a "best" spot my ladder should be?

My rechecked the CYA. It's accurate.

I did not deep clean the sand in my filter, all that's on my list tomorrow.

Should I go ahead and shock the pool tonight?

There's no mistaking the cloudiness and discoloration. Here are some items you might consider:
- When you SLAM'd before, did you remove and inspect the ladder? Those rungs/steps can hold algae easily
- Is your only return jet the one on the skimmer side? If so, lack of good water circulation to the ladder area might be a contributor
- Any chance the CYA could be higher, thereby throwing-off your required FC level?
- When you SLAM'd previously, did you also do a deep clean of the sand?

 

[#40Fan]

Yep, start another SLAM.

 

[Texas Splash]

I would increase to SLAM level based on that pic and the algae in the ladder. Best to kick it in the rear now. Should make for a faster SLAM. As for the ladder and circulation, anything hollow is an algae trap. Just the nature of stagnant water in those areas. Some people will go through various lengths to reduce algae build-up. Some will remove the ladder monthly to clean, others might even drill tiny access holes either to help the chlorinated water to penetrate, or to actually use a syringe to inject chorine into each step. Of course there's still the poles, but you get the idea. You might experiment with ladder positioning to see if it helps.

 

[aaroncp]

Brought pool to SLAM level again. Hoping for a quick one.