Does any one know of a product that can be used to remove the green mold / moss build up on boat / road covers especially in winter? Mines not bad but I like to keep the boat in the best condition possible and there are a few spots that get a light green tinge on the cover. The cover is a good quality black canvas I'm guessing, I don't want to use something like wet and forget in case it DE gradates the fabric

Wet and forget is fine.

Pollen is an issue.

Waterblast, soapy wash.
Then maintain with wet and forget or use 30 seconds.
No issues with fabric if it's good quality.

Done it for decades on multiple boats and other equipment.

If you are worried about the bleach in wet and forget, or 30 sec, then go with moss boss

30 sec doent have bleach...
PPL should start tro read labels and instructions.
Alkyl benzyl dimethyl ammonium chloride

It is more a maintenance preventive on boats / covers /bathrooms, window sills than actually cleaning as applied to house walls and paths.

I give a light mist spray.. and hold your breath when do so.. after each washdown trip out.. carpets , bimini, bimini to clears seams..etc.

Cleans the paths/ house walls because , soaks in , kills, then heavy rain over the next few months wash it all off.

Therrefore , a spray down, leave for a few days, then a good soak with something like napisan, and hose off..

And yes I use the 3500lb water blaster... sound real sever.. it only is if get close.. Done this for decades on vintage/ classic cars seats carpets, hood liners, door panels....
Thu back then, made up soln of dish wash powder, and lightly scrub on , let soak.
 This is not a detergent, it is a chemical method to 'scrubb' and release the dirt from the surface...hence no scrubbing.
 The a bucket hot water with washing machine soln.
 This is also has a 'scrubber' plus a deternent to disolve the crap into the water..
let soak but not dry.
 Then a good blast from a distance with the water blaster.

Havnt a  decent water blaster.. think about it.. about 700/$800 on special... The 1st yr you use on the house/ windows/ paths etc will have paid for its self.. and your house paint etc will last many more yrs than left unattended.. Then you also have the advantage of using to wash cars, clean the smoker racks, the kitchen oven racks, the boat and trailer,
 I got a 20m hose for mind.. dropped the end pressure a bit.. which have never needed to use other than trim the weeds growing over the edge of paths , and baddly cutting into a little toe, and a wooden rung on my step ladder.

Its only lite, appearing in a couple of places, thought bleach would break the fabric down?

Re read your post "steps"   30 sec doent have bleach...

Re read your post "steps"   30 sec doent have bleach...

 30 sec is a Brand name Not a product name.
 I refer the active chemical to look for on bottles and instructions.
So yeah , me being the "expert" and ex industrial chemist in the feild, leave it there.

Again Moss boss, even specifies canvas, sails, shade clothes etc....
Yes another alternative with alternative ingredient being
Benzalkonium chloride.
 Again careful around acrylics and clears.

I’m pretty happy with 303 fabricgaurd on mine.