Cool if its working, can't argue with that. but be ready just in case.
I used the aquarium fabric from walmart so may be different than what you have going, I don't think I paid anywhere near $40.
On my first couple indoor grows (2008-9) I tried a bunch of home brew ideas, and was running some autos along with Blue moonshine in a cab I built (threads are here somewhere I think) and they went well for a few weeks. Then bam ! like there was no filter. Those shitty little lowryders stunk like hell. (garbage smoke)
I had 4 LRIIs , and 4 BM in that first run.
Can 33 for me, worth that peace of mind.