UKPassats

after taking the carpet out due to a water leak i noticed the ac drain pipe, would i be able to completely seal where these to pipes join, previously they just had a sponge/foam type material stuck around them, or is it advisable to not seal it to prevent the water backing up any further in the event of a blockage of the lower pipe?

you can see here the quite big gap between the upper and lower pipe to the left of the round sponge thing


here is what it looked like before i pulled the foam away