Goodday . i wonder if anyone can help with this . I looking for the formula to the below problem inorder to use same to transpose in case i shoild need the pipe size in another case Two tanks , tank A and tank B. How much time in hours to fill tank B. Where Tank A is a full water tank( always being filled up from the top)of 100m^3 with a pipe on the bottom filling into tank B , an empty water tank of 50m^3 . The pipe is 100mm in diametre. Both tanks are 10 m high And where 1m^3 of water = 1 ton The problem I.m having is that the flow rate slows down as the tank fills'