Dealing with an algae problem, but I'm not even sure what kind it is.

[Robbins07]

Hi,
We noticed a few weeks back that there was a green looking algae growing in the corners of our pool and on the caulking below the tile edge and on the caulk on the tile strip on our steps. We have been battling the algae ever since with lots of shocking and it keeps coming back. More worryingly, I have not been able to clean off the algae spots on the caulk in any location with standard scrubbing of a pool brush. Today, I tried rubbing a trichlor tablet on them, and it will come off, which causes the green algae cloud to rise around the spot. However, the caulk is disintegrating as I clean it off, so this will not work either. I'm going to start the SLAM process in a few days, but I'm worried that with these caulk spots, it will just keep coming back.

So, my questions are, how do I know what type of algae I have? I'm guessing black, since the pool water itself has always been clear. Also, how do I know if the algae is alive? If it's alive, I don't see how that is as I recently shocked with 8 gallons of chlorine. I fear I may need to redo all of the caulking on the pool prior to slamming, which would be very time consuming and expensive. I've attached a picture of the step tile and caulking. The caulking and tile has been coming off slowly ever since we've lived here, so we aren't opposed to removing it, but I am hesitant to recaulk if this will set me up for algae growth again.

Thanks,
Tim

 

[Texas Splash]

So, my questions are, how do I know what type of algae I have?

Tim, welcome to TFP! Honestly, you may never know what type it is. There are hundreds if not thousands of specifies of algae. Regardless of the type, the SLAM Process is the way to go. Now is a good time since I suspect you will be closing soon. Best to get it taken care of now so you have less trouble next spring. Follow the notes on the SLAM Process page and you will do fine.

They key is maintaining that elevated FC (SLAM) level as noted on the FC/CYA Levels. It takes time and consistency, but it works. The sporadic "shocks" are virtually useless. Be sure to use liquid chlorine or regular bleach and your primary sanitizer.

Your signature is blank, so be sure to update it with all of your pool and equipment info. See my signature as an example. If you have any questions let us know. Enjoy the forum.

 

[duraleigh]

Even if the SLAM further damages your caulk (which I doubt) it's already in need of a fix so no harm really.

SLAM the pool by following the very precise directions and then let us know the outcome.

 

[Robbins07]

I have decided to remove all of the tile and caulk first. I am halfway done and the algae was hiding under the tile as well, so I don't think the SLAM would have helped with all of that hidden algae. So, I am on pace to start the slam next week

 

[Robbins07]

So, I'm completely done with the removal of the tile on the steps. Now, I am replacing the caulk line underneath the 6-inch decorative tile that goes around the top of the pool edge. This tile is about 1/2 underwater when the water is at the recommended level. The caulk here has algae spots on it as well. As I removed this caulk line, I could see the algae has gone underneath the tile. I can also see spots on the bottom 1-inch of the vertical caulk lines of this tile strip. I'm starting to worry that all or most of my tile will have to be taken off and completely redone by a professional to eliminate all of this trapped and growing algae. In the end, I can see this costing me $10,000. It just doesn't make sense to me, that a pool design would include tile and caulk that is this susceptible to algae if one mistake is made with sanitation levels. Is there another route I can go that is not so costly?

 

[Robbins07]

I have spent the last few days redoing the caulk line. I'm also going to replace any of the tile grout which is moldy or lose, next year. I'm hoping that any trapped algae will die, as water should no longer be able to get to it. I will of course try to keep my chlorine levels and/or algaecide high as well

 

[Texas Splash]

Sounds like you opened quite a can there. Hope the repairs work out in your favor.