Help me with this algae!!!!!

[Bryantom]

Have been dealing with this since last year. I have a dark green algae that grows at the water line, but only on the mortar between my stones. I use the trouble free method for maintaining my pool with liquid chlorine, and I am about to switch to salt but I would like to get this problem solved before I do the switch. Here are my last test results:
FC 8.5 I raise this to 10 when I add chlorine.
CC 0
CH 450
TA 90
CYA 90
PH 7.8

I've attached pics of the algae. Thanks in advance.

 

[S1ngram]

I'm just wondering. Does the water ever go as high on the rock as the algae grows? It looks pretty dry where the algae is growing in the top picture. Maybe the mortar is porous enough that it stays wet enough to grow algae? Is that what's going on?

Not having done this for long, I do know that the algae needs to be in contact with the SLAM level water for it to be killed by the chlorine. Have you tried a bleach/water solution and an scrub brush yet? I had another idea, in the event that your water line isn't usually that high...what if you SLAMMED the pool and draped an old towel over the algae and into the pool water. The towel would wick the chlorinated water right to the area that needed it. You may need to cover the towel with plastic if it dries out quickly.

 

[Patrick_B]

Welcome Bryantom,

I hate giving bad news on my first post to anyone, but I'll give it to you straight. If that area is intermittently wet and dry, there is nothing you can do with your pool chemistry to stop it. If it does not remain submerged, you will have to address it manually.

As for your pool, your Cya is up there a little too high, so I would caution you to work it down, and refrain from using stabilized Chlorine products at this time.

 

[duraleigh]

Bryantom,

Get a spray bottle and fill it with Clorox. Spray a light coating of Clorox on the algae/moss. After 24 hours, use a brush so you can get in there and remove any residue.

You may need to repeat this but catch it a little earlier next time and it will simply disappear in a few hours.

 

[elwood58]

I agree with the Clorox in a spray bottle solution. I have a couple of small spots in the upper part of my skimmer throat that get the same way. Clorox cleans it up pretty good.

 

[Patrick_B]

I agree completely this is the best answer. My apologies for not being more informative about how to do it. This will work perfectly.

 

[Bryantom]

Great thanks for the help I will invest in a good spray bottle and go that route. Do I need to dilute the clorox or just spray it full strength?

 

[Divin Dave]

Hi Barandon,
you can go full threngh if you want to. No harm. I believe however that 50/50 will be more than adequate though. Squirt a little and brush, then squirt a little more to get it all.

Great thanks for the help I will invest in a good spray bottle and go that route. Do I need to dilute the clorox or just spray it full strength?

 

[Patrick_B]

Hi Barandon,
you can go full threngh if you want to. No harm. I believe however that 50/50 will be more than adequate though. Squirt a little and brush, then squirt a little more to get it all.

Agreed, 50/50 will nuke it.

 

[JVTrain]

50/50 and a small pump-type chemical sprayer would be best. Something chemical resistant. Give the areas a shot probably once a week.

A household spray bottle won't last long with concentrated bleach going through it.

 

[Patrick_B]

I would try it before I spent the money on a sprayer.