Neptune Systems Siphon Break

ATK Siphon Break Replacement

This is the 1/4" to 1/4" push-fit adapter siphon break 

What it is:

It's a small, clear or white plastic push-fit fitting that connects two pieces of 1/4" RO/DI tubing.
It has a tiny hole drilled into its side. This hole allows air to enter the line when the pump turns off, breaking any potential siphon that might otherwise continue to drain water from your ATO reservoir into your sump/tank.

Why it's important:

Prevents overfilling: Without a siphon break, if your ATO pump turns off but the water level in your reservoir is higher than the outlet in your sump, water could continue to flow into your aquarium, potentially causing a flood.
Safety feature: It's a crucial safety component of the Neptune Systems ATK (Automatic Top-Off Kit).