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How much Algex, Alumabrite CBX and VS721 do I Need?


Fred Billin asked:

How much Algex, Alumabrite CBX, and VS721 will I need for a 25 foot, two toon, pontoon boat?



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If your pontoons are 25″ in diameter then the total surface area of both pontoons is about 321 sq. ft. I assume that 1/2 or less of the pontoon is in the water, therefore the wetted surface that you need to deal with is about 160 sq. ft. If you are like most pontoon boat owners you are only concerned with the outside of the pontoons, plus a bit on the inside at the front and back where they are visible co you can calculate about 1/2 the surface area plus about 20% for the front and back or about 192 sq. ft.

The amount of Algex that you require will depend on the amount, type and age of the growth. If the growth is light then one bottle will do, if moderate two bottles. If the growth is have (grass hanging off) then probably 4 bottles as you may have to go over them twice. If you have zebra mussels then you may need 6 bottles. In the last case, you will have to spray it on the mussels and let it sit for 30 to 45 minutes to soften them up. Then scrape them with a plastic or wooden scraper. Afterwards, you will have to spray the adhesive from their attachment pods to soften and dissolve those and scrape again.

Alumabrite CBX is a marine grade concentrated aluminum brightener so you cut that with water, spray it on and rinse it off. Be sure to follow the directions. If you mix it too strong or leave it on too long it will turn the aluminum white. You need to drench the aluminum and spray it off when still wet or it will streak. If you follow the directions you will turn your pontoons a shiny silver color in less than 10 minutes. If you are just going to do the visible parts one bottle should do. If you are going to do the entire pontoon then you will need two.

I recommend that since you are going to all this time and trouble to get the pontoons looking new again that you protect them with Alumetron. It’s a clear wipe on coating that will prevent future oxidation and if properly looked after will last for years.

The coverage of VS721 is 400 sq. ft. and you need 2 coats so one bottle will do as you are only coating the wetted bottom half of the pontoon. VS721 will work better if the pontoons are protected with Alumetron as it will fill in the fissures and make the aluminum much smoother so marine growth and especially Zebra Mussels can’t get a grip.

Thanks for your question,

Richard Kittar
Captain Aurora

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