Question on Battery charger

The Duel Pro XL charger that is in my boat is showing green lights on one side and 4 red lights on the other side. I came in from fishing Fri. plugged the charger in and today (Sat.) the lights are not the samer as usual. They usually go green about the same. There was a little corrosion on the neg. terminal could this have caused one of the batteries not to charge?
Thanks for any help.Stoner

Yep that could do it. A dirty connection is a quick way to shorten the battery life. We run into that at work.

Everything looks good now, I cleaned it, seems to be charged on both sides now.
Thanks,
Stoner

Also get a can of terminal protector and spray them down good after you clean them. It will help prevent it from happening again.