whats everyones thought

[drywall guy]

Is it possable to get that much sand on the bottom or could it be mustard algae. ....not my pool !!!!

 

[Texas Splash]

Mustard algae is a yellow green color and grows on the walls and floor mostly on the shady side of the pool. Dust/pollen will keep re-appearing, but will never accumulate on the walls of the pool. If you do shock the pool, mustard algae will mostly disappear as long as you are at shock level and brushing occasionally. Dust will continue appearing at the same rate when you are at shock level.

By the looks of it, I kind of doubt it is MA simply by it's location and being in the sun.

 

[pooldv]

Looks like plain old algae to me.

 

[Donldson]

Add another vote for plain old green algae. Some of it appears to be dead but there definitely seems to be a green tint to it.