OK! So you've hauled your boat, pressure washed the bottom and Boat Scrubbed the hull until it gleams. It looks great, except for that four inch greenish, brown stain along the waterline. You've tried every cleaner you have, even rubbing compound, and still the stain remains.

So what are your options? You can ignore the stain; maybe it will go away on its own. Not very likely

You can slap on the polish and deal with it next time. Wrong again. There's better than an 80% chance that the polish or wax that you apply will permanently seal in the stain and the only way to get it out is with sandpaper.

You can pick up a bottle of Aurora Waterline Stain Remover at your local marine store, apply it to the stain with a cheap paint roller, wait about 20 minutes, rinse it off and watch the stain disappear. No rubbing or scrubbing --- Honest. The hardest part is waiting 20 minutes for the chemical to work.

In case you've wondered what caused the stain in the first place, it's not industrial waste floating in the water where you dock your boat, it's algae. Gelcoat, the colored fiberglass exterior of your boat is actually quite porous. Since algae is microscopic in size, it gets into and attaches itself to these pores as well as to the surface of your hull. All that scrubbing and power washing that you did, got it off the surface, but of course you couldn't clean out the pores, they're too small.

Algae is the generic name for many thousands of species of primitive one celled or multicelled plants. They contain chlorophyll, the same stuff that makes grass green, and it's the chlorophyll that gives the stain its color. Green if the algae is alive, brown if it's dead.

Aurora's new Waterline Stain remover contains surfactants which lets the active ingredients penetrate into the microscopic pores of your hull and clean them out. In effect a deep cleansing. It also contains brighteners to counteract any residual chlorophyll. The result: a clean, bright hull.

The manufacturer guarantees that if Aurora Waterline Stain Remover doesn't get the stain out, you get your money back.

Although it's sinfully easy to use, don't be fooled. Aurora Waterline Stain Remover is a very strong chemical and the manufacturers instructions should be carefully followed. It does contain inhibitors, however, making it completely safe to use on your fiberglass hull.