Thanks for the info about the driftwood everyone =) I won't worry so much about my betta being in slightly browny water now lol.
Regarding the filter... I have no idea what it is?! It came with the tank and the packaging just said it was a "submersible filter pump". It has an adjustable flow which you can see on the side. The max is a bit high for the tank for any fish I think but the low will work well for my betta as there is no visible water disturbance. The pump works quite well with my other tank =)