Patio magic and green algae on canvas canopies

Dellquay13

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I’ve seen mention of patio magic ( and other brands of similar) suggested for cleaning green algae off canvas canopies and spray hoods. Before I start spraying it on, I would like to confirm other people have done this and not ruined their canvas? It seems counter intuitive to spray anything that cleans such tough algae onto the material that needs so much care to keep it weather proof
 

TSB240

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PM has a biocide as its main active ingredient. There is some soap but no strong acids or alkalis or solvents that might damage your canvas.
I usually spray it on neat on a windless dry sunny day. Wait till all has gone brown, wash off with a hose pipe and retreat with PM as it will act as a preventative measure.
Only apply canvas waterproofing treatments after this stage.
 

MikeBz

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I use it on teak cockpit decks and canvas with no adverse effects - but only whilst ashore as it;'s very toxic to marine life. I do dilute it fairly well (but can't remember dilution...). I put it on the decks when we come ashore for the winter and it stops them going green for virtually the whole winter.
 

RunAgroundHard

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Salt, common household salt, low cost works very well. Damp the green area, sprinkle salt onto the green area, then scrub in with a nail brush, then wash off with fresh water.
 

Dellquay13

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I slapped it on the pram hood of my 2 year laid up motor boat in quite a strong concentration, the algae and the lichen is already going brown, and the side decks haven’t been so clean in years. It’s in the boatyard so little worry about the runoff killing fish

Do I need to do anything else, wash it off in a few days? Jet wash or just wait for the unusually elusive Welsh rain?
 

Gumpy

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Used it on my covers for years, spray on walk away then a few days later its clean.
However
Never use it when covers are on the boat it contains chemical that are harmful to marine life.
I always do my covers on the drive at home for this reason.
 

ashtead

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We use it on Flexiteak decks with no adverse results
Painting on canvas actually sounds a good idea to manage run off to plastic windows mention above.
I don’t really think you need to wash off but you might want to reproof.
 

iantomlinson

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I’ve seen mention of patio magic ( and other brands of similar) suggested for cleaning green algae off canvas canopies and spray hoods. Before I start spraying it on, I would like to confirm other people have done this and not ruined their canvas? It seems counter intuitive to spray anything that cleans such tough algae onto the material that needs so much care to keep it weather proof
That stuff has harmful chemicals to rivers. Try looking at wet&forget. No chemicals. Used it for 10yrs on fibreglass, canvass,sails,wood,stainless,ropes etc etc. Spray in on and leave. Brilliant stuff.
 

PaulRainbow

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That stuff has harmful chemicals to rivers. Try looking at wet&forget. No chemicals. Used it for 10yrs on fibreglass, canvass,sails,wood,stainless,ropes etc etc. Spray in on and leave. Brilliant stuff.
You think ?

From the data sheet: https://www.wetandforget.com/downloads/SDS_USA_WetForget_OutdoorReadytoUse_05182022.pdf

Aquatic toxicity: LC50 Bluegill sunfish: 2.35 ppm 96 hours
LC50 Rainbow trout: 7.8 ppm 96 hours
Avian toxicity: LC50 Bobwhite quail: 2700 ppm 8 days
LC50 Mallard duck: >4500 ppm 8 days
 

Gixer

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That stuff has harmful chemicals to rivers. Try looking at wet&forget. No chemicals. Used it for 10yrs on fibreglass, canvass,sails,wood,stainless,ropes etc etc. Spray in on and leave. Brilliant stuff.
Just be careful where you use it as it’s very toxic to aquatic life.
 
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