The first hour after your corals arrive matters. Get it right and most corals settle in within days. This guide walks through exactly what we recommend, from opening the box to the first week in your tank.
Before your corals arrive
We dispatch on Mondays by Royal Mail Special Delivery, for delivery by 1pm the next working day. Make sure someone can take the parcel in, and have these ready:
- A clean container or jug used only for your aquarium (no soap, ever)
- A thermometer
- A refractometer or hydrometer to check salinity
- A coral dip (we use NYOS Coral Dip) and a second container for dipping
- Coral glue or putty for fixing the frags
Step 1: Open the box straight away
Don’t leave the parcel sitting around. Open it as soon as it arrives, keep the lights in the room dim, and check every coral.
If anything has arrived dead, take clear photos and email them to info@reefgro.co.uk within 2 hours of delivery. That’s what our Live Arrival Guarantee needs. Keep the coral until we’ve replied.
Step 2: Match the temperature
Float the sealed pots or bags in your tank or sump for 15–20 minutes. This brings the water inside up to your tank temperature slowly. If the corals are in pots that won’t float, stand them in a container of tank water instead.
Step 3: Acclimate to your water
Open the pot or bag and tip the coral and its water into your clean container. Then add a small cup of your tank water every 5 minutes or so, until the water has roughly doubled or tripled. This takes about 30–45 minutes.
You can drip acclimate instead (a slow drip of tank water through airline tubing), but don’t drag it out for hours. Water that’s been in transit isn’t fresh, and long acclimation isn’t better for corals.
For reference, our systems run steady at 1.026 salinity and 24–25°C. If your tank is very different, take a bit longer.
Step 4: Dip
We dip every new coral before it goes into our own systems, and we recommend you do the same. A dip helps knock off pests that can hitch a ride on any coral, from any shop.
We use NYOS Coral Dip. Follow the label on your bottle. As a guide:
- Fill a separate container with tank water. Never add dip to your display tank.
- Add the dip at the label dose. The standard NYOS dose is 10 ml per litre of tank water.
- Put the coral in for 10 minutes. Gently swish it, or puff water over it with a pipette, to help shake off anything hiding on it.
- Watch it the whole time. If it starts producing lots of slime, take it out.
- Rinse it in a clean container of tank water before it goes in the display.
- Throw away the dip water and the shipping water. Don’t let either go into your tank.
If a coral looks very stressed after travelling, it’s fine to wait a day before dipping it, as long as you keep it out of the display until it’s done.
Step 5: Place it low and gentle
Put new corals low in the tank first, in gentle flow and lower light, even ones that will end up higher. Fix them firmly with glue or putty so they can’t fall or roll into other corals.
Step 6: Light acclimation over 1–2 weeks
Corals adjust to light slowly. A sudden jump in light can bleach them, even under light that would suit them once settled.
In an established tank, move the coral, not the lights. Start it low and move it up over a week or two. Turning the whole tank’s lights down affects every coral in there, not just the new one. Your settled corals usually cope with a small drop, but turning the lights back up is another change for all of them, so do it gradually.
When dimming does make sense: a new light, or adding lots of corals at once. Turn the intensity down a little (keep the same hours) and raise it back slowly over 1–2 weeks.
What’s normal in the first week
- Shrunk back or closed: very common for the first few days, especially hammers, torches and other fleshy LPS.
- Some slime: normal after travel and dipping.
- Slightly paler or browner: it’s adjusting to your light. Give it a week or two before moving it.
Not normal: tissue peeling off the skeleton, brown jelly-like slime with a bad smell, or white bare skeleton spreading. If you see that, take a photo and email us.
Quick checklist
- Box opened as soon as it arrives
- Any problems photographed and emailed within 2 hours
- Floated 15–20 minutes
- Acclimated 30–45 minutes
- Dipped in a separate container, at the label dose
- Placed low, in gentle flow
- Coral moved up slowly over 1–2 weeks
FAQs
Do I need to dip if the coral came from a good shop? Yes. Pests can turn up on corals from anywhere, and a dip is quick and cheap insurance.
Can I just put the coral straight in? It might survive, but it’s a gamble. Temperature and salinity shocks stress corals, and skipping the dip risks bringing pests into your tank.
How long until it opens? Most open within a few days. Some LPS take up to a week.