Best Times to Dose Copepods in Your Reef Tank

How to Dose Copepods Without Killing Them

Dosing copepods into your reef isn’t complicated — but doing it wrong kills them off before they have a chance to establish. If you want your pods to survive, settle, and start reproducing, timing, placement, and filtration all matter.

When to Add Them

The best time to add copepods is after lights out. Most commonly used species (Tisbe, Apocyclops, Tigriopus, Parvocalanus, Acartia) are photophobic. Adding them at night reduces light shock and gives them a better chance to find hiding spots before daylight predators become active.

If you can’t wait for full darkness, dosing during your light ramp-down phase is still better than full daylight.

Where to Add Them

The sump is a good option — not because of flow (sump flow is usually high), but because it’s generally free of predators. Just avoid pouring directly into mechanical filtration zones. Ideal locations include the return chamber or refugium, especially if it contains macroalgae or rock.

Dosing directly into the display tank also works if done carefully. Choose a shaded, low-flow area and turn off powerheads. Aim for rockwork or areas pods can immediately cling to. Avoid dosing near overflows or aggressive pumps.

What to Turn Off

To prevent losing copepods to filtration within minutes:

• Skimmer – Turn off for at least 1–2 hours after dosing

• UV sterilizer – Disable for 6–12 hours (they will kill free-swimmers)

• Filter socks / roller mats – Remove or bypass temporarily

These systems are efficient at removing suspended particles — including copepods.

Support With Phyto (Optional in Mature Tanks)

Dosing live phytoplankton before adding pods is helpful in newer systems, but not essential for mature tanks. Established tanks already have biofilm, detritus, and microflora coating surfaces — more than enough for benthic pods and grazing nauplii.

Phyto is more useful if:

• Your tank is sterile or recently cycled

• You’re intentionally boosting pod populations

• You want to enrich pods before they’re eaten

Otherwise, it’s optional — not required.

Aftercare

Keep your tank in low-flow mode (feed mode or reduced pumps) for 10–15 minutes after dosing. This helps pods settle and grab onto surfaces instead of getting blasted into filtration. Resume normal flow afterward, but leave UV off overnight if possible.

Summary

Lights off. Filters off. Let them settle.

If you’re paying for live copepods, give them more than a few seconds to survive — or they’re just expensive skimmate.