Hang-On-Back (HOB) Filter buyer guide. Most common starter filter - clips on the back of the tank.
Hang-On-Back (HOB) Filter TL;DR
Price range: $15-$80.
Most common starter filter - clips on the back of the tank.
How hang-on-back (hob) filters work
Most common starter filter - clips on the back of the tank. Mechanical filtration captures particulates, biological filtration hosts nitrifying bacteria, and chemical filtration uses media (carbon, GFO, resins) to remove dissolved compounds.
Sizing for your tank
Rule of thumb: pick a filter rated for 4-6x your tank volume in gallons-per-hour turnover. Oversizing is safer than undersizing - cleaner water, more nitrifying surface area, more headroom for stocking growth.
Setup and maintenance
Rinse mechanical media in old tank water (NEVER tap water - chlorine kills bio-bacteria) every 2-4 weeks. Replace chemical media (carbon) monthly. Bio-media is permanent - never replace unless physically degraded.
Common hang-on-back (hob) filter mistakes
Replacing all media at once - destroys the bio-filter. Rinsing in tap water - same result. Skipping pre-filter sponges - shortens main media life. Buying undersized for the tank - leads to ammonia spikes.
Cost expectations
Hang-On-Back (HOB) Filter runs $15-$80 new. Used units in working condition: 40-60% off. Replacement media adds $30-$150 per year.
Hang-On-Back (HOB) Filter FAQ
Is a hang-on-back (hob) filter good for a beginner?
Yes - sized appropriately, all major filter types work for beginners.
How long does a hang-on-back (hob) filter last?
5-15 years with normal use; impellers and seals are wear items.
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