I mixed a box of Laterite granules with an inch or so of 2-3mm natural/pea gravel as my substrate base layer... with another inch of just the gravel over that... then finally, an inch or so of silica sand as my 'top' layer (total substrate depth approx 3 inches). The 'layering' meant I got minimal Laterite 'leakage' into the water and the small gravel gave a good 'rooting/holding' base for real plants. Don't wash the Laterite too much (you'll never get it to run crystal clear anyway). The sand does mix down eventually with some of the gravel... after 3 months, I only have a light scattering of the gravel showing - caused by the Corys rooting about - but it looks quite natural... my lfs uses Red Sea flourite(?) in their show tank... it looks nice but was told it breaks down eventually into a 'mush' that needs changing... its not cheap either!