I bought a 32oz Bayer Advanced Moss & Algae Killer that is applied by hooking up a hose and the solution is syphoned up and mixed into the water stream. I don't really trust this type of system and I want to put the concentrate into my deck sprayer and make sure it's getting applied correctly.

Does anyone know roughly what the correct concentrate to water ratio would be? Thanks.

It is illegal for any pesticide to be applied in a manner inconsistent with the label. Therefor any professional must advise you to apply it exactly per label instructions.

As to putting the applicator onto a garden hose, I would make sure that my faucet was fitted with a back flow prevention device.

I have used a similar applicator to apply miracle grow to my garden, it works very well in that application.

I used the same spray on a roof of a shed that had accumulated a lot of moss because the people who owned it previous never cleaned it. I sprayed it on just like the directions say and it worked great. I figured I would have to reapply but in a month or so it was all gone and washed away. It was pretty thick on the north side, maybe 2-3".

read the label to see if there is any other way to apply it

I'm not a specialist but would think you could probably read what the active ingredients are & maybe find one that you can premix yourself. Since you've already bought it, read the directions carefully & follow the advice given.

Are you going to put this on your lawn?

the label may be found here: http://www.bayeradvanced.com/lawn-care/products/2-in-1-moss-algae-killer/sizes

The hose end applicator is the only listed method of application and the product is labeled for application to lawn and ornamental gardens.

The 'ready to spray' label is technically incorrect because the sprayer mixes it with water as you use it. It just means that you don't have to hand mix it before use. Those hose end sprayers actually do a pretty good job. This stuff is pretty mild and I wouldn't worry about getting a little too much on the deck. You'd have to drink a bunch of it to get any ill affects at all. It's also harmless to most animals bigger than a bug.

If you really want to use a different sprayer, you can spray it from the hose end sprayer right into your other sprayer then apply it from that.