I just cycled one. Id say one thing i didnt expect is how little space there is for a heater in the second chamber. I went with the Eheim Jager 50w and it fits perfect. And i keep a mesh bag of seachem matrix in the return chamber. Another thing, I overestimated how much rock can fit in the tank so i ended up going with 5ish pounds instead of the pound per gallon recommendation. Other than that, ive got an AI prime 16HD light on it and probably getting a nero 3 tomorrow. I wanted to get a tunze ATO but ended up going with one of the bottle ATOs since i wanted to spend more on a quality powerhead. Also, make sure that your sand is not fine enough that the flow blows it around but fine enough if you want fish/inverts that’ll mess with it. I got fiji pink but im not going to be running much flow. 5gal is good for about 2 weeks of topoffs but im running the water hot rn for the bacteria so maybe itll last longer when i lower it