Pool clear but not passing SLAM overnight loss teat

[heckofagator]

our pool water has always been clear but every spring I seem to deal with yellow/mustard algae. Usually I brush it off every few days and after a month or so, it goes away on it's own.

This year I decided to try SLAM, partly out of curiosity to see the outcome. I'm on my 3rd day now, water is still clear as can be, but I'm losing a couple FC overnight.

I'm planning to keep going but really thought this would be a one or two night thing, just because things generally look OK otherwise.

I guess there enough algue in the pool that you can't see that will consume enough liquid chlorine to fail the overnight loss test?

 

[Newdude]

Algae is microscopic. How good is your eyesight?

By the time you can see it, it's a runaway train. The red flags of unusual FC loss from regular testing and/or OCLT are your early warning signs.

Be happy you have the leg up in the battle and SLAM on.

 

[heckofagator]

Ha, yeah, I figured that was the answer. Guess when I was searching on SLAM and reading, I saw a lot of green pools, so I guess I got greedy thinking 1 or 2 nights and I would no doubt be done.

 

[Newdude]

Look for all the hidden in plain sight areas. Ladder rails, light niches, etc.

I keep retelling this but it so perfectly sums it up. Somebody found a gunked up auto fill 2 years ago when they couldn't finish the slam. They probably stepped over it 200 times in the prolonged slam and it never hit them to check it.

Every. Last. Inch. Is. Suspect.

Take a (literal) step back and study each general area of the pool for secret hiding spots. Maybe you step on an auto fill cover when taking that step back.