, bakpak would be ideal on a 29 gal
. It would do the job on up to a 40 gal
tank but for your 55 gal
, I'd go with one of these: Remora, Presicion Marine HOT-1, or Excalibur HOB
. These are simply the best HOBs on the market. Check the auctions on eBay for some good deal on these.