Circulation
Circulation pump
Adds flow independently of filtration, which is the right way to give a hillstream loach the current it needs without forcing all that water through the filter media.
Short answer
A submersible propeller pump that moves water without filtering it, used to eliminate dead spots and to create current for rheophilic species.
What it does
- Creates directed current
- Eliminates dead spots
- Distributes heat, CO₂ and nutrients evenly
Strengths and where it fits
Strengths
- Decouples flow from filtration
- Cheap way to fix circulation problems in a long tank
Good fit for
- Hillstream and river tanks
- Long tanks with dead spots
- Planted tanks distributing CO₂
Limitations and where it is the wrong choice
Limitations
- Intake can injure small fish and shrimp without a guard
- Excessive flow stresses still-water species
- Additional equipment visible in the tank
Poor fit for
- Betta, gourami and blackwater tanks