Reservoirs hold and de-gas the coolant in a custom liquid cooling loop, and this category is for PC builders planning or upgrading one. The range covers over 50 models from SINGULARITY, ALPHACOOL, BARROW and STEALKEY CUSTOMS, plus CORSAIR and Bitspower.
How to choose a reservoir
Size and capacity. A larger reservoir holds more coolant, which makes filling and bleeding the loop easier and adds a little thermal buffer. Check the length and diameter against the free space in your case, because tall tube reservoirs often need room above or beside the radiator.
Mounting position. Decide first where it will sit: on a radiator, on a fan bracket, on the case panel or on a distribution plate. Many reservoirs ship with brackets or mounting feet for only some of these options, so confirm that yours fits the layout you have in mind.
Pump compatibility. Some reservoirs are designed to take a pump directly on the bottom, and most of these are built around the D5 or DDC pump standard. A reservoir without a pump interface needs a separate pump elsewhere in the loop, so check the pump pattern before ordering.
Ports and thread. Custom loop fittings almost always use the G1/4 thread. Count the inlet and outlet ports and check their positions (top, side or bottom), since they decide how neatly your tubing can run.
Material and looks. Acrylic is the most common body material and is easy to see through. Glass tubes resist scratching and some designs use metal end caps. If you want lighting, look for RGB or addressable LED support on the reservoir itself.
Reservoir brands we carry
- SINGULARITY: the largest group in our range, from a maker known for custom liquid cooling parts and its Protium case.
- ALPHACOOL: a German water cooling specialist, known for its Eisbecher reservoir series that suits builders who want a modular loop.
- BARROW: a manufacturer focused on custom loop parts such as fittings, blocks and reservoirs, often chosen for affordable colour and finish options.
- CORSAIR: offers its Hydro X series for custom loops, including pump-reservoir combinations.
- Bitspower: a Taiwanese brand known for fittings and acrylic reservoirs with many matching accessories.
- EK Water Blocks: a Slovenian brand whose EK-Quantum line includes reservoirs and pump-reservoir combos made to match its water blocks.
- Aqua Computer: a German company known for its pumps and its aquaero fan and pump controllers, which integrate with its reservoirs.
Also in our range: STEALKEY CUSTOMS and Phanteks.
Reservoir FAQ
What does a reservoir do in a water cooling loop?
A reservoir stores coolant, gives you a place to fill the loop and lets trapped air rise out of the liquid. It also keeps the pump supplied with coolant, which protects it from running dry. You can see the coolant level at a glance.
Do I need a reservoir for a custom loop?
Most custom loops use one, because it is the simplest way to fill and bleed the system. Some builders use a fill port on a radiator or distribution plate instead, but that makes topping up and checking the level harder. All-in-one coolers do not need one, as they are sealed.
What size reservoir should I buy?
Choose the largest one your case can accommodate without crowding other parts. A bigger reservoir makes bleeding easier and gives you more margin if the level drops slightly over time. In small cases, a short or slim model is often the only option that fits.
Is a pump-reservoir combo better than a separate reservoir?
A combo saves space and reduces the number of fittings and tubes needed, which suits smaller or tidier builds. A separate reservoir gives you more freedom in where to place the pump and how to arrange the loop. If you are unsure, a combo is usually the simpler starting point.
