Ok, I purchased a new design on its first year. That may have been a mistake but live and learn. My problem is that the head on occation will back up from the tank. Not much, but enough to stink. So the last time I pumped out I flushed the tank 3x, once via the vent. Went down to the boat last night (90+ deg temp) and it there was about 1/4 cup of brown water. When I backwashed the vent there was a fair amount of back pressure so I just sprayed the water there while pumping out. You could hear the air flowing in while the pump was working so I know I had the correct vent.1. Peggy says to knock out the screens on the vent. How do you do that without scratching the daylights out of the clean new (Stainless/chrome). 2. The tank is mounted in a very confounded place that is nearly inaccessable so suggestions of what