Algaecide Recommendations for a Pump Sprayer or Pressure Washer

[JoLin]

I'm no longer capable of getting under the boat and scrubbing the green stuff off the hull. My (electric) pressure washer alone doesn't do a great job. Can anyone recommend a product that'll do most of it for me? Ideally I want to use it in a garden sprayer or pressure washer, let it sit, then rinse it off. Probably tilting at windmills, but maybe somebody has had good luck with something?

My .02

 

[robert graham]

Spray it multiple times with straight Clorox bleach.....leave on a day or so....then pressure wash it

 

[GA_Boater]

Spray it multiple times with straight Clorox bleach.....leave on a day or so....then pressure wash it

Wear old clothes and spray downwind.

And Clorox is cheap and a store brand is even cheaper. Try it on test spot and see how it works.

 

[Chris1956]

There was a marine product called "Marykate on and off" or something like that. It was supposed to be a very good hull cleaner, although I never used it.

 

[poconojoe]

I use powdered oxalic acid. It cleans all that brown stain after a season in a slip. I don't know if it will definitely take off the algae, but this stuff is pretty good. My boat was filthy and even my gas powered pressure washer wouldn't take it off.
Oxalic acid is the product in most hull cleaners and toilet cleaners.
I bought it in a powder form and dilute it in water. I use a pump sprayer to apply it. Use rubber gloves and a mask or respirator to be safe. And of course don't let the wind blow it at you.
Just spray it on, let it sit for a few minutes, then rinse it off.
It worked great for me. I didn't have to crawl under there.
Look it up on you tube.

 

[Old Ironmaker]

I've tried everything for my white aluminum hull StarCraft. It is moored in a dirty scungy creek. The best I have found is a 1 to 1 combination of Lysol Toilet Bowl cleaner and Hydrogen Peroxide. It does require elbow grease. I have spent a lot of $$ on those hull cleaners sold at Marinas. I won't name them here as iboats might sell them. I didn't get it all off last fall and am going to try the Oxalic acid that @pocanojoe has recommended next week. It is basically brick cleaner I have come to learn. If it works without me re breaking my lumbar spine I'll let you know. If you find something JoLin you let me know.

 

[JoLin]

There was a marine product called "Marykate on and off" or something like that. It was supposed to be a very good hull cleaner, although I never used it.

You have the name right. I use it on the props and trim tabs. Very potent stuff- it immediately dissolves barnacles and every bit of everything else. I have to be real careful of the fumes- I can feel the 'burn' when I accidentally get a whiff. I know it'd work, but I'm afraid to apply it to a large area. I have emphysema and it could put me flat on my back.

If you use it, wear rubber gloves and eye protection. Don't leave it on too long, and flush really well with a garden hose. It really is good stuff.

I may try bleach in the garden sprayer. Thanks, guys.

My .02

 

[QBhoy]

100% certain and tried and tested. Oxalic acid is the key
buy it in powder form...1 part oxalic acid, 9 parts roasting hot water. Mix well and spray on the hull below the water line or any natural lines you have. If you are fussy agitate with a brush...leave for no more than 10 mins and simply hose off with water. Takes it right off. Incredible stuff and the base ingredient for the best of the hull cleaners....just without the BS. Trust me. It’s for sure the way forward.

 

[JimS123]

An algaecide prevents it or kills it, but does not remove it when its there.

Oxalic acid it the key.

 

[frantically relaxing]

I used nothing but Muriatic acid cut down with water to 8 to10% strength. "The Works" toilet bowl cleaner is available lots of place, some of it is still 20% but seems most is like 9%, which is okay full strength. HD sells 14% MA for swimming pools, cut it 50% water-- etc... My routine is to power wash as much of everything off as possible with my 2700psi machine. Then I load a $5 Walmart garden sprayer with the mix. The acid eats the calcium, which is what the green is holding onto. Spray a square foot worth at a time, the crud will smoke for a few seconds, then quit. At the point the acid is neutralized, so spray again-- keep spraying till that sq.ft is clean and doesn't smoke, move to the next sq.ft..Every so often rinse everything down with fresh water... I could completely clean the 26' Chaparral in about an hour, using about 1.5 gallons of mix and and the pressure washer, and nothing else. Muriatic acid is just one of many, like oxalic, or even vinegar, that will work. I've had great luck with it, and it's dirt cheap. One caveat, keep it off the stainless...

 

[Bob_VT]

Visit a Pool supply place and use Chlorine in the pressure washer - household bleach is 3-6% sodium hypochlorite and pool chlorine is usually 12-15% - it will BLIND YOU if not used properly so wear proper PPE

I have used it for cleaning decks and siding in a pressure washer.

PLEASE be careful and good luck