Ideal Home for Betta? -- Eclipse? Custom? I'm Confused!
This is a discussion on Ideal Home for Betta? -- Eclipse? Custom? I'm Confused! within the Beginner Freshwater Aquarium forums, part of the Freshwater Fish and Aquariums category; -->
The filter chamber is the reservoir inside the filter. Just fill it all the way up with tank water....
The extra will usually drain out back into the tank. The heater you have will probably be ok, but get one of the tank thermometers with the suction cups and stick it in the tank so you can monitor it. If it fluctuates a lot then you should probably order that Marineland heater I gave the link to earlier (I did, right?)...it's a 10 watt but will keep the temp steadier. The hydor mini-heater's a bit trickier in the summer months, especially when you don't have AC and the house temps go up and down.
The two compartments are probably so you can use more than one kind of filter media. You should be fine, they're pretty water resistant. Just make sure you don't pour water into anything that looks like it has electrical wiring- but usually you have to unscrew stuff to get to anything like that.