I power washed the pontoons after being in the water for 2.5 months and the power washer did a fine job of cleaning most of the river crude off. I am staying away from using acid to clean them since the power washer did the job.
I have a 36 year old Lowe 16 foot Aluminum fish boat. Some power washing with no acid in the St. Lawrence & other fresh water. Never leaked any where. Including 1 overcharged battery & acid drip to floor. Aluminum is a lot tougher than people think it is.
I use bottom treatment. Not paint. When Lake Erie warms up enough, I jump in and scrub the bottom. My treatment doesn't really stop the growth, but A] slows it down and B] easy to wipe off. I'm in the water anyways.
Sad thing for this year and beyond, I have a little less then half a bottle remaining. I think I have the last bottle ever manufactured. It's no longer around anywhere even in Canada where it is/was made. I tracked down the person in charge and he tried to con me into giving him my CC and he'd ship me some treatment. I didn't take the hook!
This stuff was amazing. One coating underneath and you're done for the season. No need to polish it. It did what it stated. The alternative is awful. Two coats of heavy paste. While it works just the same, it is hard to apply forcing me to crawl around under the boat and over the axles. No fun. But the cost of the paint....
The nice thing about trailer boating is that after 29 yrs. I have never washed the bottom. The owner before me had put bottom paint on, so I had to also. I put on a moisture barrier and then a product of long ago called VC-17
I know the off shore racing boats use several SUPER SLICK coatings to keep very clean. My marina & others REFUSE to lift any super slick boats. They slide right off and into the racks or on a slope. But for laziness of physical limits ? You just need to bow lock the hull every time. My Lake Ontario water slimes were wiped off instantly with a couple of figure 8s. I wore it off in 2 full summers. Each summer I signed a Lawyers Release for the marina. That was too much for the marina not being responsible.