My 1500 only has/had about an inch of sand and the rays have shifted it all to the back now so I have half a tank with no sand and the other half has 2" a deep bed. 
Question is, if I bring the sand bed up to 2-3" deep will this cause any health issues (Black sand syndrome), dead pockets of poisonous gas in the sand or anything like that?
Will the sand just end up all in the back again like the thin layer of sand?
Thanks

Question is, if I bring the sand bed up to 2-3" deep will this cause any health issues (Black sand syndrome), dead pockets of poisonous gas in the sand or anything like that?
Will the sand just end up all in the back again like the thin layer of sand?
Thanks