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Respected Contributor
Posts: 2,510
Registered: ‎11-08-2020

I bought the outdoor kind from Amazon.  I followed the directions and then thought ...this doesn't work.  I did one section of concrete.  It did not work right away but, over time I see this section of concrete is better than the rest.  You have to let it sit for awhile.  I think the directions were to use it when it is sunny for a few days to give it time to absorb.  I am going to reapply on the rest of the concrete pathway.  

The high pressure washer cleans ok but is hard on concrete I find,

Trusted Contributor
Posts: 1,999
Registered: ‎03-11-2010

For outside, I use  HOME ARMOR ....works great.

Esteemed Contributor
Posts: 6,766
Registered: ‎05-09-2010

@Foxxee wrote:

@Puppy Lips @Hoovermom.

 

Both of you said Wet and Forget outside didn't work for you.

 

Did you know rain washes the algae off and it must come down, hit the area that has algae on it?  

 

Wet and Forget kills the algae, but needs rain to wash it off.  

 

If it doesn't rain, or doesn't hit the algae areas, nothing happens.

 

It might take several months for rain to hit your house at the right spots.  Raining straight down onto your house will not remove the algae.  Rain hitting the other side of your house where there is no algae will not work.  

 

I spray mine in the Fall letting the rain take care of it over the winter.  It's gone in a few months.

 

It's a lot better than pressure washing the house every year only to have algae starting up again in a few months.  You can clean the algae off first, then spray and it will keep algae away for a year.  I don't want all that work.  

 

 

 


@Foxxee I sprayed some on the side of my screened in pool, in a concrete area behind the hot tub.  Yes, it is a short verticle "wall," like 12 inches high.  It does look slightly better, but in no way is cleaned off.  I will just have to pressure wash that off.  Thanks for your comments.

Always remember that you are absolutely unique. Just like everyone else. Margaret Mead