Tuesday, February 17, 2015

Another Chemistry Experiment

Remember these spots?

Look close - there's algae there too

Well, I did some research - it is such a wonderful thing to have the bulk of Man's knowledge at your fingertips!

Guess what?  Algae, moss and lichens suffer grave bodily harm when exposed to a particular class of chemicals.  Well I guess that part is not a surprise.  But this part is:  that family of chemicals is relatively harmless to virtually everything else.  In fact, it is the active ingredient in Bactine:  benzalkonium chlorides.

Now here's the next surprise.  No, you don't have to buy 100 bottles of Bactine and distill it to get the benzalkonium chloride - all you have to do is go to the pool/spa section of your local hardware store and buy a bottle of HTH Algae Guard:

And it was less than $10!

This is a 30% solution, and yet a 2% solution is supposed to be adequate for killing algae/moss/lichen.  

So, the first test is a kind Hippocratic one.  Does this stuff harm the Sunbrella canvas on the boat?  I uncapped the bottle and put some of the straight 30% solution directly on a scrap of our Sunbrella and left it to dry.  After rinsing it out 24 hours later, there was no detectable effect on the canvas.  At 30%, the solution has a blue tint - I suspect this is just a dye for appearances, given its intended use. Our canvas is green - if yours is white, you might want to repeat this test.

The next test is underway right now.  I made up a 6:1 dilution (5%) solution in a hand spray bottle and applied it to a section of the deck with the lichen, and a portion of our canvas which has a liberal infestation of winter algae on the outside.  I also applied it to the inside of the canvas directly over our galley vent where we get the most amazing colonies of...  well, life I guess, apparently feeding on whatever the vent delivers to the canvas.

I'll let you know how this works out...

Update:  Results are here.



Anonymous said...

PNW is a remarkable place in all respects. Aside from the natural beauty of the area, it's the only place I know where you can stand still for ten minutes and spawn algae, lichens, and mildew. Everybody needs a good algaecide in PNW. But, I still love it there and would move back at the smallest pretense.

Robert Salnick said...

Rick, mildew is our state flower!

Anonymous said...

Any update on this one?

Robert Salnick said...

Anon -

Yes: it worked!

I'll put up some pictures this weekend.

Also, Jane sprayed some 3% solution on moss on our drive way and in our yard... It all died. No effect on the grass at all.

This is magic stuff!


Nora said...

Hi Robert,
Thanks so much for all your useful tips! I really like your scientific approach,the experiments and the explanations. I put a link to this article on my site
Just starting out with all this boat and sail fixing stuff and finding it fascinating.
Your blog really helps to understand things and how to approach finding solutions.
I really appreciate all the work you've put into your blog! Thank you.

Robert Salnick said...

Wow - thanks Nora for your kind words!


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