I finally got my hands on a 90 gallon, so I will be upgrading from my 40 this coming weekend. Right now there is 6 Malawi high-breds(2-3 inch right now) in there that I inherited, feel bad getting rid of them so I will stock around them. OK back on topic, I have about 60-70 pounds of sand in the 40G I don't think that will be enough for the 90. I don't want to go through the hassle of cleaning sand in the apartment, bathtup tends to clog. Can I mix pebble substrate with the sand? has anyone done this and can put some pics up. any tips will help, the 40G is going away completely for now so everything in there is going to the 90.