Treat New Dock?

[Dad207]

Just replaced my dock -- its pretty big, 20 x 15 with a U -shaped boat slip and an access pier. Pressure treated pine , of course, but wondering if I should use a commercial sealant. There is alot of discussion on line about the advantages-- protection from sunlight and water, snow absorption, but I have also heard that once treated you've got an ongoing maintenance issue, need to power wash and re-treat every 3-4 years. That may not be the worst case, but interested in a variety of views.


--Treat or no?
--Product experience
--Maintenance post treatment
--Environmental-- what can I use, and to what degree must I prevent dripping into the Lake?


I do know that I need to let it dry out-- 3-6 months.
Input very much appreciated.