Collection: ATO Systems

The problem it solves

Topping off by hand means level and salinity swing between the moment you notice the drop and the moment you correct it. Automating the job removes the swing: fresh water goes in as it is lost, and specific gravity holds where you set it. For most reef keepers this is the single most useful piece of automation on the system.

How kits differ

• Sensing - optical sensors dominate, usually with a second sensor or a mechanical float as a backstop.
• Delivery - a supplied DC pump, or a solenoid valve plumbed straight into a reverse osmosis line.
• Standalone versus controller-linked - some kits log and alert through an aquarium controller, others run entirely alone.
• Sumpless kits - hang-on designs for aquariums without a sump.
• Liquid level sensors - sold on their own in several lengths for depth readings in a sump or reservoir.
• Automatic water changers - units that swap out a set volume on a schedule.

Installation notes

The failure mode that matters is a top-off that keeps running, so build in redundancy rather than trusting one sensor. Position sensors clear of bubbles and surface turbulence, keep the outlet above the water line or fit a siphon break, and fill the reservoir with fresh water only. If a kit ships with a backup float valve, install it. Choose a reservoir capacity that puts refills on a weekly rhythm instead of a daily one. Email info@jlaquatics.com to match a kit to your setup.