I haven't used that particular product but have tried others. I've also posted in earlier threads on this subject. All those products seem to do the job in varying degrees. They do take some time to work, but they do work without the extra work and problems associated with bleach. If applied in the fall and early spring (like right now) it has noticeable effects in about 10 months. I have used the type that is pre-mixed (around $13.00) and you attach it to your garden hose. It works but there doesn't seem to be enough in the bottle to do a thorough job on a large roof. There are other brand with a heavier concentration for about 30 bucks that will cover a larger area.

There is also a zinc (and a copper one if you prefer) strip that you can add to your roof just under the shingles above the moss and the streaking caused by it. This kills the growth and thus the cause of the streaking. Find an obscure spot on the roof if you care to test it. Put a penny just above a moss spot and watch it for a few months..the moss will die and the stain will wear away.

The moss usually grows on the most northern exposures of the roof. It is usually caused by the lime used in the shingles which the moss feeds on, instead of the asbestos in older shingles.

I just mix a high concentration of RoundUp in a hand held pump sprayer and apply. In a week or so, I then hit the area with a pressure washer and no more moss or stain.

Thanks for the replies. I am familiar with the many options to remove moss (bleach, zinc strips, power washing, etc.), but was seeking comments on these two products in particular. Mainly curious as to how well they work and what they have as their main active ingredients. BTW, we have a concrete tile roof.

Doctor told me once that I was getting older and wiser and I had probably reached a stage in life where its going to be cheaper to pay someone to do some things than it will be for me to visit him and the other doctors and hospitals when I push myself physically. Not that I can't do it he said.. but he knew I could afford to enjoy a little bit of life more so than when I was a younger man.

I had roof cleaning service about annually for concrete barrel tiles .. pressure clean and mildew-cide here and hope to sell you a paint job .. pretty cheap actually to let someone else walk around up there for half a day. Lots easier on the legs and back too.

Hope depot has some magic powder thats really designed for asphalt.. but it should stick on moss. Not fast but works over time.

mikie: Totally agree with you and your doctor! Given a choice between my bleach and wire brush work vs. hiring someone to pressure clean, there is no question which way my body would vote. We did hire a pressure cleaner several years ago. They did a great job, but the price was steep. Yeah, I know it's a no-brainer if you compare it to doctor and hospital bills, etc. So this Wet & Forget stuff sounds like a happy medium, IF it works as advertised. I'll check out HD; might be something similar. Thanks for the tip.