Mag 250 would be plenty for that tank, I had a 350 on my 75 and it would be too much for a 30.
Once it gets established it polishes fairly well, if you want to put the polishing filter in for a couple hours once or twice a month it will polish wonderfully but that's a lot of filter changing. After a couple weeks the batting that surrounds the media cartridge gets a nice layer on it and the filter really polishes well anyway.
Hang your AC50 on your current tank for a couple weeks before you do the tank swap and you will have a nice start on a decent bacteria colony and it should speed up your cycle time.
Once it gets established it polishes fairly well, if you want to put the polishing filter in for a couple hours once or twice a month it will polish wonderfully but that's a lot of filter changing. After a couple weeks the batting that surrounds the media cartridge gets a nice layer on it and the filter really polishes well anyway.
Hang your AC50 on your current tank for a couple weeks before you do the tank swap and you will have a nice start on a decent bacteria colony and it should speed up your cycle time.
