Question for betta experts

I have built a ten gallon tank, divided into four compartments (plus a
2.5" backplane for heater and filter) following the designs shown
he

http://www.petfish.net/tank_dividers.htm
http://www.gntbs.org/dividedtank.htm

The silicon has cured, several washings of water have gone through it,
and is now all set up and ready to go, with an Ebo Jager heater and a
Zoo-Med Microclean 304 submersible filter (http://tinyurl.com/y9cc).

The 304 is vibrating (sub-question below) and making a 60 Hz hum,
which may annoy the fish in the tank, and which certainly annoys me
since it's on my desk. My question is, do I really need filtration is
this tank at all? For now, it will have just two bettas, with up to
four eventually. There is a gravel base for eventual build up of
bacteria, and the tank has been seeded with water from established
tanks. I'm good about doing water changes regularly.

I do want to have a very mild current in the water to ensure good heat
circulation.



Sub-question - The impeller on the Microclean 304 doesn't seem to
actually spin, but rather it oscillates back and forth. I've tried
cleaning the impeller as well as the space it fits in, with no effect.
Is this thing supposed to spin, or is mine broken?

Sub-sub-question - If filtration is a good idea, and I replace the
Microclean, which is better: the "Duetto Multi Filter 50" or the
"Fluval 1 Plus Internal Filter 50GPH"? I initially tried a Penguin
Mini because I'm fond of bio-wheels, but it caused too much splashing
(water level is about 1.5" below tank edge).


Thanks in advance.


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www.ericschreiber.com