ThetfordDrain Valve Lubricant - 24oz

Just an idea: would it be advisable to add some of this to the tanks as part of the winterization process ?

How long can I leave the lube in my tanks?

I see conflicting information in the answers: does the product float on top or sink in wastewater?

Getting ready to pour this down the gray tanks but I don't think even a half a bottle will even get past the P traps, can anybody weigh in on this???