how the auto water changer works!

auto topup kit - pro3
auto topup kit - pro3
auto topup kit - pro3
auto topup kit - pro3
auto topup kit - pro3

auto topup kit - pro3

Regular price
Regular price
Sale price
Unit price
Sold out
Tax included. Shipping calculated at checkout.

ATU-Pro3 fitted with an infrared sensor


This unit has been designed to be put straight into use with only a suitable container for reservoir being required.

includes pump/pipe/mounting etc 

overseas shipping available

via first class royal mail signed for £4.60 (UK)


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 or Pro4 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 - 6 types plus the reefer available
  • pipe - 5mm int 8mm ext
  • 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 2m head height
  • anti-wave - 3 second delay on pump activation

Customer Reviews

Based on 7 reviews Write a review

Customer Reviews

Based on 7 reviews
Martin Cowling
Don’t hesitate to get this ATO, you won’t regret it.

Being new to saltwater aquariums I got my reefer 170 a few months ago and soon realised how unreliable the stock ATO was, it was driving me nuts. Looked online and kept seeing the Reefloat Pro highly praised in the forums. Gordon was very responsive helping me choose the option for me. Easy to install and worked straight away, reliable and keeps my levels spot on. The support from Gordon has been brilliant, somehow I’d managed to mess a setting and Gordon emailed me a fix within an hour on a Sunday evening!

Alice cockerill
Best customer service

I went with Reefloat because of the impressive customer service record, which was not wrong. I cant imagine there is a better product out there for the job but what you are also buying here is the best customer service in any industry I've come across. Worth every penny! should I have any reason for future purchases I will stick with reefloat

Great reliable auto top up

Great auto top up that I use on my Red Sea reffed 425XL. Never failed or missed a beat, great product and great customer support.

Joe veitch
Brilliant bit of kit

Has never let me down! Great product, I would consider this an essential for keeping salinity solid.

The best.

The features I love are the level sensor, which is very accurate and only needs a quick wipe every 6 months or so. And the auto off so it stops after 60 seconds - feels much more secure and it's great to have a fail safe. It also has an alarm to tell you when this has happened.

The wave detection is also brilliant - means the pump doesn't freak out when you put your hand in the sump!

Bought it to replace the stock ATO in my Red Sea Reefer (which was rubbish!)