- What is an ATO?
Great question!
An ATO, which is actually an abbreviation,
or short, for Auto Top Off
is any device that will automatically
add fresh water back to the aquarium to replace water
that is lost through evaporation.
And I'll walk you through the most popular type of ATO
in just a little bit,
but first, let's look at why you would even want one.
Anyone who has had an aquarium
will have experienced the drop in water level
within that aquarium
or the sump that happens over the course of a few days
and then had to grab a jug
or a bucket of fresh water to fill it back up
to the same level that it was at before.
An ATO basically takes that job off of your plate
by making sure that the wire level
in the aquarium stays consistent all the time,
which does have a few important benefits,
especially for our saltwater aquariums.
So, why is it important to prevent evaporation
from getting out of hand?
Because it is actually important.
First off, salts don't evaporate.
So if the water volume decreases,
the salinity increases,
which can be problematic for sensitive fish
and the majority of invertebrates and corals.
Nutrients like nitrate and phosphate
along with the concentrations of other water parameters,
will also become more concentrated,
which can definitely become problematic
for the health of the aquarium.
Another issue that an ATO solves
is preventing equipment from becoming exposed to air
and running dry.
A good example is aquarium pumps
like a return pump or a circulation pump,
which could become damaged if they begin pulling in air,
as well as aquarium heaters,
which can overheat and break
if they're plugged in while being out of the water.
For those important reasons among others,
making sure that the aquarium is consistently topped up,
especially in a reef aquarium,
is super important,
and topping off by hand is certainly doable,
but it's just impractical for the majority of us.
And hence, the auto top off,
also known as an ATO,
was born.
There are two basic types of ATO to choose from:
gravity fed and pump driven.
Gravity fed ATO systems require the reservoir of fresh water
to sit above the water line of the aquarium,
or the sump,
and typically use a mechanical float valve
to stop and start the flow of fresh water.
As the water evaporates from the aquarium,
or sump,
the float valve lowers
and opens up to allow water to flow.
And as the water level rises back up,
the float valve closes to shut off that flow of water.
Gravity fed ATO systems are awesome
because they don't require power or a pump,
but the float valves do need to be maintained
and replaced periodically
to make sure that they're always working perfectly
and don't leak,
which could cause all the remaining water
in the reservoir to flood the aquarium,
or sump.
One drawback to gravity fed ATOs
is that unless your aquarium comes with one
like a lot of the Red Sea aquariums do,
you'd most likely need to make a DIY version
for your aquarium by getting a float valve,
a suitable container,
some tubing and fittings.
It's not exactly hard to do,
but if you just want to buy an ATO
and set it up,
then a pump driven ATO is likely what you're after.
A pump driven ATO uses a small pump to push fresh water
from the reservoir to the aquarium, or sump,
which means you can have that reservoir sit below
or even at the same level as the aquarium,
or sump.
This allows you to mitigate the risk
of the reservoir ever accidentally flooding the system
like a gravity fed ATO can.
Most pump driven ATOs are digital
and use a small controller with either optical sensors,
float sensors,
or even both
to detect the water level
and immediately add fresh water
when this sensor is tripped,
which often translates
to a smaller amount of water evaporating
between top offs
and less fluctuation in water chemistry.
Pump driven ATOs will also typically
have some sort of internal programming and extra sensors
to act as redundancies to prevent them
from ever accidentally flooding the aquarium or the sump.
And in some cases, they have both
like the Tunze Osmolator 3155,
or even the Neptune Systems ATK.
Pump driven ATOs are by far the most popular,
and there's a wide range of them to choose from
to fit all sorts of budgets and aquarium setups.
And they're definitely the type of ATO that I recommend
for new and seasoned aquarium hobbyists alike.
But, before anybody goes out and gets an ATO
for their aquarium,
you're gonna wanna make sure
that you avoid the most common mistakes
that people make with their ATO,
especially because one of them is seriously devastating.
So watch this top 20 video right here.
We go through all of the most common mistakes.
They're super easy to avoid if you know about them.
So enjoy and save yourself a lot of hassle.