Ok i just got a tank for free my other is at my friends house so ill use this one for now. the tank size is 3 ft long, 21 in tall, 12 1/2 width. i believe its a 50 gallon. i was wondering what type of filter system should i get. i was thinking of a marine land 350B. i have 3 small reds going in there untill i can get my 75 gal from my friends house. i was wondering what would work the best. it also has a undergravel filter in there i will prob leave it in there i guess it cant hurt. my other question is were can i buy parts to the UG filter. i need a cap to plug a hole and some UG small filter and elbows because right now all it has one the top is a protective thing that fish cant swim down into. just wondering what you all would recomend.