Red Sea ReefCan 18 & 40 — Vertical RO Water Reservoir for Auto Top Off ATO Systems

The Red Sea ReefCan is an RO water reservoir built for the auto top off (ATO) of reef aquariums. Available in two sizes — 18 liters and 40 liters — it uses the most underused dimension of your cabinet: height. The result is more RO water in reserve on less floor space.

Our advice

People often use cheap containers for their ATO — it does the job, except it eats a lot of space. The ReefCan is made to hold a big volume of water right in the side of the cabinet: you save a ton of room, and there is no jug of water sitting in the middle of the living room or the kitchen. Once again, Red Sea did not invent reservoirs — they improved them.

What the ReefCan does better than a bucket

• Slim vertical design: more RO water for less floor space.
• Transparent body with an embedded water scale: see exactly how much water is left without opening the lid.
• Front opening: positioned so you can refill the reservoir without moving it.
• Dedicated rear opening for cables and tubes: once your pump is set up, you never disconnect anything except for occasional maintenance.
• Designed for the ReefATO+: it holds the syphon breaker of the Red Sea ReefATO+, while remaining suitable for most ATO systems.

Specifications (manufacturer data)

• ReefCan 18: volume 18 L (5 gal) — height 55 cm (22"), width 9 cm (3.5"), depth 44 cm (17")
• ReefCan 40: volume 40 L (10.5 gal) — height 55 cm (22"), width 17 cm (7"), depth 50 cm (20")
• Red Sea's stated autonomy: one week of ATO water for a 200 L (50 gal) tank (ReefCan 18) or a 500 L (130 gal) tank (ReefCan 40)
• Slides in beside the sump — even in the REEFER 170 and 200 according to Red Sea — or behind the cabinet

Complete your top off setup

• Red Sea ReefATO+ 3-in-1 — the smart ATO the ReefCan was drawn around.
• Kamoer ATO One SE v2 — another ATO option that pairs well with the ReefCan.
• Red Sea ATO float valve — to automatically shut off the RO fill of the reservoir.

Why buy your ReefCan at ReefSolution

We are an authorized Red Sea dealer. Our team in Laval can help you pick the right size for your tank and your cabinet. Shipping across Canada.

Frequently asked questions

Which ReefCan size should I choose for my aquarium?

Red Sea states one week of ATO autonomy with the ReefCan 18 for a 200 L (50 gal) tank and with the ReefCan 40 for a 500 L (130 gal) tank. The stronger your evaporation — lighting, flow, dry air — the more the larger size makes sense.

Does the ReefCan work with ATO systems other than the ReefATO+?

Yes. Red Sea indicates it suits most ATO systems — the rear opening takes the pump and its cables — but it is specifically designed to hold the ReefATO+ syphon breaker.

Does the ReefCan fit inside a REEFER 170 or 200 cabinet?

Yes. Red Sea states the ReefCan slides into the gap beside the sump, even in the REEFER 170 and 200 models. Otherwise it can also go behind the cabinet.