I am building a 50/50 viv for my fbts and was wondering if putting the substrate mesh over the pebbles before the moss & dirt really helps keep the water section clean? I am going to use some real plants & a small filter so I don't want to have to disrupt the tank to clean it all the time. I am going to have a small filter in the water. Also, could I use some regular left over window screen or do I have to buy the stuff they sell for the aquariums? Thanks!