Aquarium Chiller Buying Guide Australia: Sizing, Fans vs Chillers, and Standby Power

Brisbane summers push tank water well past the mid-20s, and once a reef sits above 28 degrees for weeks at a time, corals stress, oxygen holds less well in the water, and pest algae gets comfortable. The question every Queensland reefer eventually asks is whether a fan will do the job or whether it is time to buy a proper chiller. This guide walks through the sizing math by litres, the real difference between drop in and inline units, and what that compressor actually costs you in standby power at 240V.

Table of Contents

• Cooling fan vs dedicated chiller
• Sizing a chiller by tank litres
• Drop in chiller vs inline chiller
• Standby power draw and running costs
• Comparison table
• Good, Better, Best picks
• FAQ

Chiller vs cooling fan for a reef tank

A cooling fan works by evaporation. Air moves across the water surface, pulls heat out through evaporation, and you top up more freshwater to replace what left. It is cheap, it is quiet enough for most lounge rooms, and for a lot of QLD tanks under 200 litres in an air conditioned house, a good clip on fan or two mounted over the sump is genuinely enough to shave 1 to 2 degrees off a hot afternoon.

The catch is fans only fight the gap between water temperature and room temperature. If your garage or patio setup sits at 32 degrees ambient with no air con, a fan is just moving hot air around. It cannot pull water below room temperature, and on stinking hot days in January it will lose the fight completely. That is when a compressor based chiller earns its keep, because it actively refrigerates the water regardless of what the room is doing.

Rule of thumb we use in store: if your system is under 150 litres, sits in an air conditioned space, and you are chasing a 1 to 2 degree buffer, start with fans from our cooling range. If you are running a larger reef, an unconditioned space, or corals that are fussy about stability such as Acropora, budget for a chiller from the start rather than buying a fan twice and a chiller anyway.

Sizing a chiller by tank litres

Chillers are rated in horsepower (HP) or by cooling capacity, and undersizing is the most common mistake we see. A chiller that is too small will run constantly, struggle on the worst days, and wear out faster. The rough sizing bands below assume a typical QLD summer where ambient can hit 30 to 34 degrees and you want to hold reef temperature around 25 to 26 degrees.

These bands assume decent lid coverage and no direct afternoon sun through a window onto the glass. If your tank sits near a north facing window in Brisbane, size up one bracket. Sunlight through glass adds heat load that the litre count alone will not show you.

Drop in chiller vs inline chiller

Drop in chillers use a coil that sits directly in your sump, with the compressor and fan sitting external to the water. They are simple, there is nothing extra to plumb, and they are usually the cheaper option for a given cooling capacity. The trade off is the coil takes up sump space and adds one more thing crowding your baffles.

Inline chillers, like the TECO TK 150, plumb into your return line so water flows through the unit and comes out already cooled. No coil sitting in the sump, cleaner installation, and generally easier to service because the whole unit sits outside the cabinet footprint. Inline units need a dedicated pump feed and a bit more plumbing know how, plus fittings such as the Aqua One inlet outlet 12mm bulkheads to get water in and out cleanly.

For most home reefers moving from a fan setup to their first chiller, inline is the more forgiving option because it does not compete for sump real estate. Drop in chillers still have a place on tight budgets or where plumbing an inline loop is impractical.

Standby power draw and running costs at 240V

A compressor chiller is not running flat out all day. It cycles on when the setpoint is reached and idles or shuts off in between. Standby draw, meaning what the unit pulls while idle or in low fan mode, is usually under 30 watts on most home reef chillers. The real cost comes when the compressor kicks in, which on a unit like the TECO TK 150 draws in the range of 150 to 300 watts while actively cooling, depending on ambient heat load.

Run the numbers roughly like this: if a chiller cycles for 6 hours a day during a Brisbane heatwave at an average 200 watts while active, that is 1.2 kWh a day. At typical QLD residential rates, that lands somewhere around 30 to 45 cents a day just for cooling, more on the worst 38 degree days. It is not nothing, but it is a lot cheaper than losing a colony of SPS to a heat spike. Plug your chiller into a dedicated outlet, label the cable with something like Gallery Aquatica cable management labels so you are not chasing cords behind the cabinet during a water change, and keep it on a GPO separate from your heater circuit so a fault on one does not take out the other.

At a glance comparison

Good, Better, Best

Good: Fan first, upgrade later

Start with fans over the sump if your tank is under 150 litres and the room has air con. Cheap to trial, easy to add a chiller later if summer proves fans are not enough. Browse the cooling collection for options that mount without extra plumbing.

Better: TECO TK 150 inline chiller

The TECO TK 150 at 850 AUD is the workhorse choice for systems in the 150 to 400 litre range. Inline plumbing keeps your sump clear, and it is a proven brand in Australian reef rooms. Pair it with proper Aqua One 12mm inlet outlet fittings for a tidy install.

Best: Cade system with cooling sized in

If you are building new, look at a Cade Pro Reef 600 S2 at 2499 AUD or step up to the Cade Pro Reef 1200 S2 at 3599 AUD. These systems are engineered around known volumes, which makes chiller sizing straightforward rather than a guessing game. For anything approaching display centrepiece scale, the Cade Reef S2/P 1800 at 6499 AUD gives you the cabinet space and plumbing runs to fit a chiller cleanly from day one.

FAQ

Can I run a chiller and a heater on the same tank?

Yes, and most stable reef setups do exactly this. The chiller handles summer heat spikes, the heater covers winter nights. Just keep them on separate GPOs where possible and check your controller logic if you run one through a controller, so they are not fighting each other on the same setpoint.

Do I need a chiller in Brisbane or is fan cooling enough?

Depends on your setup. Air conditioned house, smaller tank, forgiving livestock, fans can genuinely cover you. Garage tank, larger system, or SPS dominant reef, budget for a chiller because a 34 degree January afternoon will beat a fan every time.

How noisy are aquarium chillers?

Most home units sit around 40 to 50 decibels while running, similar to a quiet fridge compressor. Inline units tend to be a bit quieter than drop in units of the same capacity because there is no coil vibration transmitted through the sump glass.

Will a bigger chiller than I need cause problems?

Oversizing wastes money upfront but is not dangerous. It will short cycle a bit more, meaning it reaches setpoint fast and shuts off, but that is far less damaging than an undersized unit running flat out all day and still not keeping up.

Prices quoted above are accurate at the time of publishing and are subject to change. Please check the relevant product page for the current price before purchasing.