• Dymax Slim Flo SF-500, HOB Filter, Large
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Dymax

Dymax Slim Flo SF-500, HOB Filter, Large

Dymax Slim Flo SF-500, HOB Filter, Large

$35.99
$35.99
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Hang-On-Back Filter for Planted Tanks 10 to 24 Gallons

The Dymax Slim Flo SF-500 Filter is a hang-on-back filter rated for freshwater aquariums from 10 to 24 gallons. It delivers up to 125 GPH through a wool carbon cartridge that handles mechanical filtration and basic chemical polishing in a single pass. For hobbyists running a mid-size planted tank or community setup who want dependable filtration without the cost, footprint, or plumbing of a canister filter, the SF-500 covers the range cleanly.

At 125 GPH, the SF-500 turns over a 24-gallon tank more than five times per hour at full output. The adjustable flow dial brings that down for tanks with plants requiring lower surface agitation or community fish that prefer calmer water. The intake sponge protects small fish and shrimp from being pulled into the unit, and the leveling knob handles rims that are not perfectly level.

Key Features:

  • Hang-on-back design requires no drilling, no plumbing, and no sump, fitting tanks with standard rimmed or rimless construction
  • 125 GPH max flow rate handles tanks up to 24 gallons with multiple daily turnovers
  • Adjustable flow dial scales output down for planted tanks with CO2 injection or sensitive community fish
  • Wool carbon cartridge provides mechanical and chemical filtration in one replaceable unit
  • Quiet motor operation suitable for living room and office setups
  • Intake sponge prevents small fish, shrimp, and fry from entering the intake
  • Leveling knob ensures a stable hang on rims that are not perfectly flat
  • Replacement cartridges are sold separately as a 2-pack (DM-SFC-L)

Ideal For:

  • 10- to 24-gallon planted tanks and community tanks that need consistent mechanical and chemical filtration without a canister filter
  • Hobbyists stepping up from a smaller tank who want more flow capacity without committing to a canister or sump setup
  • Breeders and grow-out tank keepers who want a simple, reliable HOB filter that is fast to clean and easy to maintain

Pro Tips:

  • Run the SF-500 alongside CO2 with the flow set lower, not higher. High surface agitation from a filter at full output drives off CO2 faster than your system can inject it. Dial the flow back until you see gentle ripple rather than turbulent surface movement, and your CO2 efficiency will improve noticeably.
  • Add a pre-filter sponge to the intake if you are breeding fish or keeping fry. The included intake sponge protects most small stock, but a dedicated pre-filter sponge adds another layer of protection and extends cartridge life by catching larger particles before they reach the media.
  • Replace the cartridge on a schedule, not when flow slows. By the time the SF-500 shows a visible flow drop, the cartridge has already been undersized for your tank load for at least a week. Set a recurring reminder to swap it every three to four weeks regardless of how clear the water looks.

Online exclusive: this item is ordered in for you and is usually ready within a few business days. Choose in-store pickup, local delivery or shipping at checkout.

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