Listen man i went through the same decision making process my whole piranha career. I started with a 55 gallon rbp tank then when i discovered the blacks i bought a 65 gallon to accompany the reds once my black started murdering the others. so with two tanks, a 55 and a 65 i said hell with it and went to a 150. I stayed there for two years or so until it sprung a leak and i had to tear it down to repair it. so then i had a 55, a 65, and a 150 all up and running. after i got the 150 re-silliconed i tore down the 55 sold it and went with the 65 black tank and the 150 rbp tank. But the 150 always seemed to look smaller as time went on and i got more comfortable with the up-keep. So just this last year i also bought my own home and decided to go all the way!!! I decided on the 350 gallon long. This motherFin tank is Bad Ass and i absolutly have no regrets on going as big as i could. So my advise Just wait it out and GO BIG when you can!! Trust me people will marvel!! If not you might always regret not going big time. it will be easier down the road if you wanna add fish or what have you but i promise that you will not regret going with the bigger tank, just be prepaired for the work that a biger tank has in store.