Setting up a sump is one of the best upgrades you can make to a reef or fish-only system. A well-designed sump adds water volume, hides equipment, improves filtration, and makes maintenance easier. This sump setup guide walks you through planning, plumbing, and tuning your system so it runs quietly and reliably.

Planning Your Sump: Size, Sections, and Layout

Before you buy anything, match your sump to your display tank and goals.

Choosing the Right Size

A good rule of thumb is to aim for a sump that’s 25–40% of your display tank volume. For example, a 75-gallon tank pairs well with a 20–30 gallon sump. Make sure the sump can:

• Fit under your stand with room to remove equipment
• Hold extra water during power outages (test this!)
• Provide enough space for a skimmer, heater, and return pump

Common Sump Sections

Most hobbyists use a simple three-chamber layout:

• Intake/Skimmer Section: Water from the display enters here, usually through filter socks or a filter roller and then your protein skimmer.
• Refugium or Media Section: Optional area for macroalgae, live rock, or media like carbon and GFO.
• Return Section: Houses the return pump and often an ATO (auto top-off) sensor. This is where evaporation shows up.

Pro tip: Keep the skimmer section at a stable water depth by using fixed baffles, and let only the return section fluctuate. This helps your skimmer perform consistently.

For more on matching equipment to your system, see our reef tank equipment checklist.

Plumbing Your Sump: Drains, Returns, and Noise Control

Reliable plumbing is key to a quiet, safe sump setup.

Drain Options

• Single drain: Simple, but louder and less safe. Best for small tanks.
• Herbie or Bean Animal: Uses multiple drains for near-silent operation and redundancy. Ideal for larger reef systems.

Use unions and ball or gate valves on your drain and return lines so you can remove equipment and fine-tune flow without cutting pipes.

Return Line Tips

• Size your return pump for 3–5x display volume per hour after head loss.
• Add a check valve and proper return outlet height, but never rely only on the check valve.
• Drill a small anti-siphon hole just below the waterline on the return outlet to limit back-siphon during power loss.

Pro tip: Before stocking your tank, turn off all power and watch how high the water rises in the sump. Mark a “max fill” line and never fill above it.

If you’re still planning your main display, our beginner reef tank setup guide pairs perfectly with this sump walkthrough.

Tuning, Maintenance, and Everyday Use

Once water is flowing, take time to dial in your system.

Dialing in Water Levels and Flow

• Adjust your gate valve on the main drain (for Herbie/Bean) until the overflow box runs nearly silent.
• Set your skimmer to match the recommended water depth from the manufacturer.
• Use a marker to note ideal water level in the return section for quick visual checks.

Simple Sump Maintenance Routine

• Rinse or replace filter socks every 2–3 days to avoid nitrate spikes.
• Empty and clean the skimmer cup weekly.
• Wipe salt creep from plumbing and the rim of the sump.
• Test your ATO regularly to prevent pump burnout in the return chamber.

Over time, you can expand your sump with reactors, a refugium light, or additional monitoring gear. When you’re ready to upgrade, check out our advanced reef filtration options for ideas.

A thoughtfully planned sump transforms your aquarium from a simple glass box into a stable, easy-to-manage system. By choosing the right size, organizing your sections, plumbing carefully, and sticking to a basic maintenance routine, you’ll enjoy clearer water, happier livestock, and a quieter tank room for years to come.

Sources

• Sprung, J. & Delbeek, J. C. The Reef Aquarium (Volumes 1–3).
• Fenner, R. M. The Conscientious Marine Aquarist.
• Manufacturer documentation: Reef Octopus, Sicce, Ecotech Marine, Red Sea sump and overflow design guides.