I was at Petland shopping for a filter for my new 75 gal tank and the guy told me that the filter (HOB) that said it could filter up 90 gal would do barely anything for my tank. He then tried to persuade me into buying this huge engine filter that cost over triple the price of the filter I saw. I then went to Petsmart and they said that the same filter would work fine and a lady said she has used it herself and it works great. I decided to go with Petsmart and bought and installed my filter. I don't plan on changing it but it would be nice to know if I made the right decision and if not what are ways I can improve filtration without spending too much?