Step-by-step
Step 1: Position the sumpIn the cabinet under the display. 25-40% of display volume. Allow 4-6 inches of headroom for equipment access. Verify level with a bubble level.
Step 2: Plumb the overflow drainFrom the display's drilled overflow box, run 1.5" PVC to the first chamber. Use a Herbie or Bean Animal silent overflow design - eliminates noise + air gurgles.
Step 3: Set up the skimmer chamberFirst chamber receives water from the overflow. Place skimmer here at the manufacturer's recommended water depth (typically 7-10 inches). Skimmer cleans before water flows on.
Step 4: Add a baffle bubble trapAfter the skimmer chamber, install acrylic baffles (3 panels alternating up/down/up) to slow flow + trap microbubbles. Stops bubbles from reaching the display.
Step 5: Set up the refugium chamberMiddle chamber: chaetomorpha + reverse-cycle light. 1-2 cups of chaeto per 50g system. Run light during display lights-off (stabilizes pH).
Step 6: Set up the return chamberLast chamber: only the return pump. The return chamber level fluctuates with evaporation. ATO adds RODI here.
Step 7: Plumb the return pump1" PVC from return pump up to the display. Add a true union ball valve for flow control + maintenance access. Add a check valve to prevent siphon backflow during power loss.
Step 8: Test the system without livestock48-hour dry test. Verify no leaks, overflow drain handles full return pump output, sump return chamber doesn't overflow when display refills, ATO triggers correctly.
Frequently asked questions
How big should an aquarium sump be?
25-40% of display volume. Bigger is better for stability + skimmer + refugium space. A 75g display benefits from a 30g+ sump.
Do I need a sump?
Not required. AIO tanks (Innovative Marine Nuvo, Waterbox) integrate the sump function. But sumped systems offer larger water volume + easier equipment management for tanks 40g+.
How loud is a sump?
Properly designed (Herbie or Bean Animal overflow): nearly silent. Poorly designed: gurgles + slurps loudly. Always plan the overflow type before building.