6 Best Auto Top Off System Options For Your Tank

Today, an increasing number of cutting-edge technologies are finding their way into the fish-keeping hobby. Among the most popular of these technologies is the top-off system, which makes frequent top-ups of aquarium water easy.

However, if you’ve heard of this equipment for the first time, it can get challenging to pick a suitable addition for your home aquarium. So, I’ve compiled a list of the 6 best top-off systems. Let’s get started to the list:

Best Auto Top-Off Systems

Tunze Osmolator 3155

The Tunze Osmolator 3155 is a premium auto top-off system built to last for saltwater aquariums up to 26 gallons in size. These durable ATOs are made with high-quality materials and are widely regarded as superior to the competition. It helps significantly maintain your tank’s water level and keep your tank full of clean water.

The Tunze Osmolator 3155 is the gold standard auto top-off unit today. The device features manual and digital sensors that work together to control and monitor your tank’s water level. Tunze Osmolator 3155 features a shut-off mechanism, which shuts off the pump if it goes too long without being used to monitor things like the aquarium overflowing. Additionally, a notification feature will notify you when the pump continues to use and the water level rises above a certain cutoff level. The pump itself is a high-quality Tunze model.

XP Aqua Dueletto ATO

The XP Aqua Dueletto ATO is designed for large aquariums and all-in-one tanks for automatic top-off systems. It’s marketed internationally as the smallest duel-sensor top-off system for reef tanks, providing you with greater protection from the failure of one of the two sensors.

The components of the compact unit do not require mechanical movement, and it is equipped with a digital intelligent sensor.

It works efficiently in low-light and dark tanks, and the dual-component system lets you put it anywhere behind a combined tank. The pump included with the system is also small, making this ideal for use with all-in-one chambers.

The dual intelligent sensor system makes it less costly than rival top-off sensors, and it comes with a pump. However, the sensors work better than others and can mount magnetically.

P.S. The dual sensor system also works as a safety feature.

JBJ Auto Top-Off

While the JBJ Auto Top-Off system offers excellent value for the money, it’s not the best device on the market.

The JBJ is a little more complicated to install and set up than other systems, and it doesn’t come with a pump or power supply.

And that’s probably one of the reasons why I’ve listed this top-off system at the end of this list.

You can purchase a pump and power supply combined with the JBJ on Amazon to save yourself some trouble, but you lose some of the advantages of buying an ATO. In particular, your ATO doesn’t have to be close to your tank or sump if you have a separate pump/power supply unit.

Hydor Smart Level Controller

All the best automatic top-up systems are connected to a sump – an extra tank that holds excess water. The Hydor, Smart Level Controller, works in this way, and it has a dual-sensor design to make sure your fish are never left high and dry.

A dual sensor is always better than a single sensor because one can fail at any time. This system has two sensors that work together to monitor the water level. If one fails, the other will ensure that your fish tank doesn’t overflow or become too low in the water.

The main parts of this system are the electronic controller and a plug with two sensors. The installation process is very straightforward, as you have to place the sensors in your sump and connect them to the controller unit. You don’t need to connect any wires directly to your tank, which helps keep everything neat. The controller also has an alarm system with sound and lights if something goes wrong with your water level so that you won’t miss any warnings.

IceCap Dual Optical ATO

The IceCap Dual Optical ATO unit features two digital sensors that assess your water level and give a timer that indicates maximum and minimum levels. It also comes with good-quality pumps and suction cups. In addition, the system alerts you when your reservoir runs low, so you won’t need to check it yourself.


The EPPTECH Automatic Top Off (ATO) system is a budget-conscious and compact unit that uses a digital optical sensor to detect when water levels need topping off.

One drawback to this factory is its nonreliability management section. Devices may malfunction or catch on fire, suggesting the need to replace them frequently. Therefore, it is crucial to check the equipment’s internal integrity of its magnetic board and the optics in the naked eye.

This can lead to some messy flooding accidents, which are never welcome. But for most people who want an ATO that won’t break the bank – which is what you should expect from an ATO in this price range.

Besides, suppose you don’t mind having a bit of soldering involved in its installation (rather than plugging it straight into your light) and are prepared to deal with any problems. In that case, this is an excellent product that can easily be self repaired.