I'm setting up a new tank and want to have a little sand 'stream' in the middle of it. The main susbtrate is Azoo Plant Grower bed. The 'stream' will only be about 2 inches wide. I have some flexible tubing I got at Home Depot last night and I've cut it to basically be the 'shape' of the stream as well as the side walls to keep the sand out of the substrate. Sand will go in the tubing itself (open on top, picture a U made of of tubing). Is there anything flawed in this thinking? Will this work? I could make just little walls and let the sand sit on the tank itself. Will there be any problems from keeping the sand off the bottom of the tank and in this tubing? I'm sure some will drift out of course. Thanks in advance!