Good plumbing makes a reef tank safer and quieter. It also makes maintenance easier. This guide covers the core parts and how to set them up.
Plan the system and set target flow
Start with a simple drawing of your sump and stand. Mark the drain path and the return path. Keep runs short and avoid sharp bends. Every elbow reduces flow.
Pick a turnover rate that matches your goals. Many mixed reefs run 3–5x display volume per hour through the sump. A 75-gallon tank often targets 225–375 GPH at the return outlet. Higher flow belongs in the tank via powerheads.
Match overflow capacity to your real flow, not the pump box rating. Measure head height from sump waterline to return outlet. Add loss for fittings and valves. A “800 GPH” pump may deliver 450–600 GPH at 5 feet.
Choose drain style early. A Herbie uses two drains and runs very quiet. A BeanAnimal uses three drains and adds extra safety. If you have one drain, keep flow lower and accept some noise.
- Target 3–5x sump turnover for most reefs
- Plan for power outage back-siphon volume in the sump
- Leave room to remove pumps, socks, and skimmer cups
For related setup basics, see reef tank sump setup. If you are still choosing an overflow, check overflow box options.
Build reliable drains and a safe return line
Use PVC for most hard plumbing. Schedule 40 is common and strong. Use unions near pumps and bulkheads. Unions let you remove parts without cutting pipe. Add a true-union ball valve on the return for easy service.
On a Herbie drain, set the main siphon with a gate valve. Place the gate valve below the overflow and above the sump. Start the return pump and close the gate slowly. Stop when the emergency drain only trickles. This keeps the system quiet.
Keep drain outlets under the sump waterline to reduce splashing. Add a short section of flexible tubing to cut vibration. Avoid check valves as your only flood protection. They can fail from sand or snails. Drill a 1/8-inch siphon break hole just under the display waterline.
Use strainers on overflow standpipes to block snails. Keep return nozzles close to the surface. Test the outage volume. Turn off the pump and watch the sump rise. Leave at least 1–2 inches of freeboard after the drain down.
- Use gate valves on siphon drains for fine control
- Install unions at pumps, bulkheads, and manifolds
- Drill a 1/8-inch siphon break hole on the return
If you plan to feed reactors, consider a manifold. Tee off the return with small valves. Use 1/2-inch lines for media reactors in many systems. Keep each branch on its own valve and union.
Leak testing, noise control, and common mistakes
Do a freshwater leak test for 24 hours. Fill the system and dry every joint. Wrap a paper towel around bulkheads and unions. Even a slow drip shows fast. Tighten bulkheads by hand plus a quarter turn.
Noise usually comes from air in the drain or water falling too far. Raise the sump water level near the drain outlet. Add a filter sock or a small baffle box. On a Herbie, adjust the gate valve in tiny steps. Wait 30–60 seconds between changes.
Microbubbles often come from a skimmer section that is too turbulent. Reduce return flow to 3–4x and let the skimmer do its job. Add a bubble trap with three baffles spaced 1 inch apart. Keep the return pump intake away from the drain outlet.
Common mistakes include mixing metric and standard fittings, or skipping primer. Use PVC primer and cement on slip fittings. Use thread sealant paste on threaded fittings. Avoid Teflon tape near pumps and unions. Bits can clog impellers.
- Freshwater test for 24 hours before saltwater
- Hand-tighten bulkheads, then add 1/4 turn only
- Adjust gate valves slowly and wait 30–60 seconds
For long-term stability, keep your return section level stable. An auto top-off helps a lot. Learn more in auto top-off basics.
Sources: Reef2Reef plumbing guides and build threads; Bulk Reef Supply plumbing and overflow tutorials; “The Reef Aquarium” by Delbeek & Sprung.
Reef tank plumbing does not need to be complex. Plan your flow, use unions, and test for outages. A quiet drain and a safe return will protect your reef for years.
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