I just got a  36 gallon bow front fish tank. I'm planning on getting goldfish of course, but I am not sure of what size filter I should get. Just wondering if anyone as any suggestions? I have been looking at a penguin 350 but I was told that was too strong and my fish would get sucked in. The Emperior was suggested as a more suitable choice for my size of tank. Please help me! Thank you in advance for any advice you can give.

you could go with both, but definately dont go with anything more powerful yet. since you are just starting out, i can give you some better ideas as to what jargon you are probably sifting through on the filter boxes.
never pay attention to how many gallons the filter says it can handle, because if you follow that with a goldfish tank, you will get frustrated and angry because it will most likely be too weak to handle the enormous waste goldfish produce. for aquariums 50 gallons or above with more than 7 fish within, go with a canister, stock it with filter media to eliminate all nitrogen based watses(this means NO2-,NO3-,NH4+) and also baceria which will keep the filter clean so you don't have to take the canister apart and fix it every month or so.
the only thing that the rating of gallons a filter can take is useful for is adding 10 gallons to it and finding a filter with that capacity on it. if you understood that, congratulations, because it was confusing. if you didnt, here's what you do: figure out how many gallons your tank is, add 10 to that number, and find a filter which says it can support how many gallons your new number turned out to be. for example, you have a 30 gallon tank. add ten to that, giving you 40. now, look for a filter that says it can handle 40 gallons, and go with that one. if, like in this case with a 36 gallon tank, you aren't going to find a filter rated for exactly 46 gallons. in this case, round up to 50, and buy a filter for a 50 gallon tank.
pay attention to what kind of cartridges your filter takes. i run a bunch of tanks and try to keep the same type of filters on all of them so when i go to a store im not buying 50 different kinds of filter cartridges.  my filter of choice is the double-wheel Emperor 400 for tanks under 40 gallons (currently i have a 40 gallon and a 36, like you gldygrlcpht, and two 400's on a 90 gallon on either end. (so i cheated a little...but big stuff lives in the 90 gallon with no chance of getting sucked into the filters)

i agree with the canister filter recommendation. I replaced the over the top (water fall type filter) with a canister filter and it has cut down my maintenance tremendously. The water is always clean.  A canister filter costs more than your average filter but it's well worth the money in the long run. 

So far I have had my tank running for 3 weeks and all is going well except the ammonia levels keep going up. I have lost 2 fish so far. I am only keeping 2 to 3 in there at a time to start things out. Do you think getting another small filter will help that?  Nitrates and Nitrites have been great...none. PH is a bit high.

Hi there, first timer here!
We have just aquired a goldfish and tank. There was no filter installed so I'm gonna install one I already had. It's just a mini internal filter but I no longer have instructions. Can anyone give advice on fitting it please? It's pretty small with four suckers on one side, a vent on the opposite side with a little sticky-out bit where water seems to stream out (causing no bubbles!). It has a little tube also, with a stopper thing in the end which I'm guessing sits out of the water? Not sure if it's supposed to?! Also, if whole filter system should be submerged in water? I'd appreciate advice on this as I've been surfing net for three hours now with no success. Many thanks. 

Or... it could be as simple as sticking the suction cups to the side of the tank, and putting it deep enough under water so that the little pipe where water comes out is completely submerged. (By the way, there is usually a little marking on the filter how deep it should be under the water.)