Red Sea ReefControl ATO Module — Auto Top-Off for Lite and Pro Controllers

The Red Sea ReefControl ATO Module adds automatic top-off to your system — and it does not work alone: it requires a ReefControl Lite or Pro controller. Connected to the controller, it compensates evaporation continuously: the sensor watches the sump level, the pump brings RO water from the reservoir, and ReefBeat logs every millilitre — daily top-off volume becomes a tracked metric of your tank.

What the ATO module does for a reef tank

Evaporation pushes salinity up every day — and salinity stability is one of the keys to reef keeping. The ATO module locks it down: constant level, constant salinity, no daily watering can. In ReefBeat you see the volume added day after day; a consumption that suddenly changes is often the first sign of a problem — open lid, leak, weakening pump.

Installation — know this before you buy

The level sensor mounts directly in a Red Sea sump. Outside a Red Sea sump, Red Sea states a sensor holder is required (manufacturer parts R35629 or R35623, on request). The module connects to the controller's dedicated port — it does not use up a ReefSense probe port.

Frequently asked questions

Does the ATO module work on its own?

No. It requires a ReefControl Lite or Pro controller — the controller drives it and sends the alerts in ReefBeat.

Does it take up a probe port?

No — it connects to the controller's dedicated connection. Your ReefSense ports stay free for measuring probes.

Does it work with another brand's sump?

Yes, with the appropriate sensor holder: Red Sea offers holders R35629 and R35623 for non-Red-Sea sumps — write to us and we will order them.

How is it different from the ReefATO+?

The ReefATO+ is Red Sea's standalone top-off; the ReefControl ATO Module is the ecosystem version: same mission, but driven by your controller and logged in ReefBeat with the rest of the system.

Why buy from ReefSolution

ReefSolution is an authorized Red Sea dealer in Canada — no customs or exchange surprises. The module connects to the ReefControl Lite or Pro. Shipping across Canada and expert advice in-store in Laval.