I have a 20gal high tank. Right now it has the stock Topfin20 HOB. I have that spidey sense tingle that its not going to last long. I want to start looking for an upgrade now. Im slowly moving towards a more planted tank so i dont think it will really handle alot. My problem is ive only ever had HOBs, never anything else. I know canisters are better, especially after reading about them i think thats the route i should go. Ive also read they are not great with sand, which i have. Its a pretty coarse sand, the corys barely disturb it. Any suggestions?