how the auto water changer works!

atu-pro3 - 12 litre
atu-pro3 - 12 litre
atu-pro3 - 12 litre

atu-pro3 - 12 litre

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ATU-Pro3 - 12 litre fitted with an infrared sensor

new low profile!

D:420mm W:200mm H:150mm (height does not include the cap - add 50mm)

This unit has been designed to be plug and play

includes pump/pipe/mounting etc 

shipping £12.50 uk mainland


Here are a few scenario's that have been reported on reef sites and what the ATU-PRO3 does if it happens.

  • The float physically jams because of a snail or similar
  • The float fails electrically
  • The float drops into the tank
  • The outlet comes adrift resulting in water outside the tank
  • The reservoir runs dry (possible pump burn out}
  • The pump gets jammed
  • and most important R.O. reservoir "dumps" its contents into the aquarium

In every situation above only the ATU-Pro3 will shut the pump down after a time period set by yourself with the options of 5, 10, 20 or 60 seconds. - exclusive to Reefloat - NO other brand has this facility

The ATU-PRO3 is pre-wired and the unit is ready to use - includes:

  • The programmable controller
  • Supplied with infrared sensor and bracket with 2m flex
  • A low voltage pump with a maximum height of 3 metres
  • A 2amp power supply
  • 2 metres pipe
  • full installation guide



In a nutshell it shuts down the pump so the top-up is inoperative until you come along and reset it, indication that it has shut down is via the pump LED starts flashing and the alarm sounds for 30 seconds, sounder then repeats for 2 seconds at 15 minute intervals. Reset is a simple push of the button, once to silence the alarm and twice to full reset - if the cause of the fault is still present then it will go back into alarm state


BONUS - Anti-Wave - many are familiar with the pump switching on and off every time you stick your hands in the water, or the same things happens if you have that powerful wave maker powerhead. This is addressed by a 3 second built in float delay activation, in other words the water level has to be "LOW" for 3 seconds before the pump starts, as soon as the level reaches a "HIGH" position the pump stops immediately. The distance between high and low level is not measurable by conventional means the sensor is that accurate!

BONUS - Memory - that preset time you set up stays unless you reprogam, it is not lost on power failure!


  • sensor - HQ infrared
  • sensor cable length 2 metres
  • sensor mounting - magnetic
  • water level variance - less than 0.5mm
  • voltage - 12v DC
  • alarm - visual and audible programmable 5-60 seconds, pump auto cut-off on alarm
  • pump - 12v DC with up to 3m head height
  • anti-wave - 3 second delay on pump activation

Customer Reviews

Based on 2 reviews Write a review

Customer Reviews

Based on 3 reviews
Kenny Culross (Dundee, GB)

Well made and reliable product that makes life easy. Had mine for a year now.
Great customer service as well.

Justin Green
Hassle Free

These do what they say, with no bother and no fuss. Plenty of reviews on the web about ATOs and Reefloat fairs well in them all.
The alarm facility is great and the timer options for maximum run time are a must, stops the whole resevoir being dumped into the tank if a fault delivers.
Had mine over 3 years now and the only issue has been a sensor that failed, hardly suprising considering the job it does; this was quickly and easily replaced and I see there is yet another new development with sensor technology. Time for another upgrade maybe.

100% reliability

I've had this ATO after years now and it has never failed me...not once.
To me its the best