Hello I`v recently had 2 sewer line clogs in my basement in the last month and one about 1 1/2 yrs ago . i am in a 4 level sidesplit house with 1 toilet on the uppermost floor and one on the second basement level both of these are dual flush lo flow models upper is the costco 1 piece and the lower is a foremost 1.6 / 1.1 one piece straight side model . we had the cleanout scoped to the main and found 2 low spots one about 20 feet out and another at 70 feet , the first one is about 4 feet long and sags about 4 inches the second about 2 1/2 feet long and sags about 1 1/2 inches the plumber said i should replace the lower toilet with a more powerfull flush/higher gpf model that would "break things up and not cause a plug of waste to get stuck in the sags in the house to main line" ,i`m not finding any more than 1.6 gpf toilets here in ontario canada at the big box stores, can i just remove the 1/2 inch of tank insulation that is applied to the inside side and bottom of the foremost`s tank and realize an increase in gpf and pressure ? i`m thinking without doing any real math that it might get to 2 gpf .the only other idea i had was to extend the height of the flush mechanisms 2 inches or so "i know finding /making parts to do this could be a hassle lol but i like a challange" i guess my only other option is getting a old toilet from a reclaim store as spending the $2500-$3500 for replacing the sagged sections or $7000 -$10,000 to replace the entire pipe is outta the question right now.