Hey fishlorians, So I'm building up my wishlist of things for my new 30gal. Next on my list is filtration. I want to divide the bioload between two filter systems so I have some redundancy if one of them craps out. I currently have some guppies and am planning to get some shrimp later down the line. Maybe some ottos. I might also explore breeding the guppies. The tank is planted, too, and I'm not sure if I need to consider surface agitation if I ever get a CO2 system. I'm thinking the best bet for a filter system is a sponge filter (great for shrimp and fry) and a HOB to provide a bit more kick (either an aquaclear or a bio-wheel - haven't decided). , I could even go double sponge. If I fully commit to the plant route and want to stay away from surface agitation, I could go to a cannister filter and a sponge filter with a powerhead, but I assume that'd be very bad for fry and shrimp! If anyone has any other suggestions on good filter setups, or any general opinions on this idea - whether you think it's good, not so good, whatever you think. I'd love to get some more opinions. Also, will a HOB fit on the back of a tank if the top is a little bulky where the lid sits? I assume it doesn't need to just be naked glass. Expertise/experience appreciated! Equally if I'm overthinking all of this, tell me that too. Edit: I should also mention that this tank is in my bedroom, so noise is a consideration.