Sand Substrate

IMO sand will usually look dirtier, because the debris will stay on top rather that working down into crevices...that said cleaning is usually eaiser....just kinda swish the water right above the sand with the syphon thingy instead of sticking it down into the sand. It might also be a good idea to get some MTS (Malaysian Trumpet snails) because they will stay down in the sand and usually keep it from getting anaerobic pockets. IMHO I think that VERY fine gravel works better than sand......it doesnt move around quite as eaisly...yet most any fish that needs to bury themselves, can still do that with ease....FWIW

I have silica in my tank, it looks great and is really easy to clean. If you have messy fish like a pleco, their droppings will be much more noticable though. If you buy a darker color sand it will be much harder to notice.