Silica sand is also used in pool filters / I guess my concern is if it will have a detrimental effect of fish or cause them health problems from being too fine, or takes too long to settle and clouds the tank, also from a cleaning it point of view it might be just small enough to go all the way up tank vacuum etc / its about the same as beach sand in gauge.  Ryan do you have algae build up issues with your sand?  and if so how do you deal with it?