I have placed four bags or fluorite, seven lbs.of pure laterite and two lbs of natural pea sized gravel to total four in. in a 56 gal.tank. I cleaned the substrate with the gravel vac. and this causes a huge mess due to the dust that I could'nt rinse away in the beginning.I have'nt cleaned the substrate for somtime now,so what is the worst that could happen? I do 30% changes biweekly, run CO2 and ferts.