Algae on Cement Above Water Line

[michaelpdough]

My pool has just developed green something-or-other on the vertical side of the cement deck which is (obviously) above the water line. We had a lot of rain over the last months here in Florida, so for a few weeks, it would actually go above the line, but not for long. The green is especially bad in the corners, and on the sandier side of the pool.

So, what do I do? Slamming does not seem like an effective method, as the water will not touch this area. Using a brush and chlorine or bleach seems like an idea that would only cause the pool to grow green.

Thoughts?

 

[YippeeSkippy]

Can you post a pic of this area?

 

[Isaac-1]

I would try bleach diluted with water in a misting spray bottle.

 

[michaelpdough]

Here's a pic of the (by far) worst part. Notice the black above to the left, and to the right. That is around the entire pool in patches -- again on the shady side. I have not really been able to remove it. I have tried scrubbing, even tried a bit of acid with a wire brush -- it worked but seemed dangerous! Could these be related (the green and the black, that is.)

If I use the spray bottle with bleach should I just plan on slamming right away?

- - - Updated - - -

I have no idea why the picture is upside down.

 

[Isaac-1]

I would wait on the full SLAM for now, but it might be a good idea to boost your FC level up to SLAM level temporarily to cover any bits that may fall in the water. You probably also want to make sure you are in misting not spraying mode on the trigger bottle.

 

[michaelpdough]

Issac-1, that worked incredibly well on the green. I will up my testing regiment over the next 48 hours to keep my eye on the levels to see if anything strange happens and if a SLAM is required.

Now what about the black? It is very much like in the picture. Much worse in the corners and worse in the shady areas than the straight sun-filled ares, but it is present everywhere. The picture is actually of the place where I used acid and a brush -- worked to remove the black, but I was afraid for my safety. (I never intended to do the whole pool, just wanted to see if it would work.) I have tried bleach in various concentrations, but that did not seem to kick it!