Hey, I've got a quick, rather insignificant question about my octopus tank. I recently went out and bought about five feet of 4" diameter PVC pipe for my octopus tank, and cut off two 20 cm lengths to put in the water. Unfortunately, I neglected to realize that PVC pipe does, in fact, float. For now I have the pipes loosely grounded in the water by the weight of my substrate, but is there a more permentent way to fasten these bad boys? Also, for light, I'm just using a reading-type lamp with a thirty watt bulb aimed right in the middle of the front of the tank. Is there a better way to do this?