Things You'll Need
Plastic cleaning gloves
A pontoon can refer to a complete boat or the floats that support the boat platform. Pontoons can be constructed from a variety of materials, though most popularly from lightweight aluminum. While it is common, boats that are stationed in water for long periods of time attract mineral deposits. In order to remove lime deposits from a pontoon, there are several cleaning and care techniques that you should implement, which will ultimate increase the longevity and quality of the pontoon.
Remove the pontoon or boat from the water. If you are an expert swimmer or diver and feel comfortable cleaning the boat's pontoon while it is still in the water, then you can ignore this step. For safety reasons, however, it is recommended that you take the boat out of the water in order to thoroughly clean it.
Fill a large bucket with clean, warm water.
Add 1 cup of Calgon powder to the bucket and mix. Depending on the size of the pontoon, you may need to add additional Calgon powder, but follow the Calgon box instructions for the exact powder to water ratio.
Put on a pair of plastic cleaning gloves.
Scrub the lime deposits with a slightly rough sponge (but not a metallic sponge or scrapper). Depending on the amount of lime deposit is on your pontoon, you may need to scrub for several minutes, completely covering the pontoon with lather.
Wash the cleaning mixture away with clean water. A garden house works especially well for large pontoons.
Allow the pontoon to air dry. Repeat the cleaning process if lime deposits remain.
The lime scales are created by calcium and magnesium in water, which is why you need to use a product like Calgon, which contains sequestrants, an agent that work at deactivating calcium and magnesium. If there is a tremendous amount of lime buildup on your pontoon, there may be nothing that you can do to reverse the buildup. Regular cleaning products will not work to deactivate these lime scales.
Do not use harsh chemical cleaning treatments on your pontoon, as they can damage not only the boat but can also infiltrate the water system where the pontoon is floating.