ULTRA RUNNING HYDRATION BLADDERS & RESERVOIRS

Start by checking the reservoir capacity your running pack is designed to accept. Some packs have a dedicated compartment or internal sleeve, while others simply provide a hanger and space within the main compartment.

A 1 litre reservoir gives a compact setup where relatively little water is required. Around 1.5 litres is a useful balance for many ultra runners because the reservoir can remain slimmer and hold the water in a more compact area against the back.

A 2 litre reservoir gives more reserve for longer sections, hot weather or uncertain water availability. It does not need to be completely filled, but the additional capacity is there when required.

Three litres is much less common for ultra running because the water itself adds considerable weight and takes up substantial pack space. It is more relevant where long unsupported sections, self-supported running or fastpacking require greater water capacity.

Do not choose capacity from race distance alone. Consider the time or distance between water stops, expected conditions, terrain, pace and your own requirements.

A baffle limits how far a reservoir can expand when filled. This keeps the load flatter and closer to your back, reduces bulging into the rest of the pack and can make a filled reservoir easier to return to a tightly packed compartment.

Baffling also reduces water movement and sloshing. For running, these advantages can be more useful than simply maximising the reservoir's stated capacity.

Some reservoirs allow the baffle to be opened for additional capacity. Most runners are likely to benefit from keeping it closed for the slimmer, more stable shape unless the extra water is genuinely needed.

Neither system is automatically better.

A reservoir gives very easy access to water through the drinking tube. There is no need to repeatedly remove a bottle or flask, drink from it and return it to a pocket. It also leaves the front pockets available for food and other equipment.

Soft flasks make it easier to see approximately how much fluid remains and are generally simpler to remove and refill. They also leave the rear compartment free for clothing and other kit.

Some runners use both. A reservoir might carry plain water while front soft flasks contain additional water, electrolyte drink or carbohydrate drink. A soft flask can also provide useful backup capacity if a reservoir, hose or bite valve develops a problem.

After filling the reservoir, remove as much excess air as practical before returning it to the pack. Turn the reservoir so the air reaches the hose outlet and draw the air out through the bite valve.

This reduces sloshing and helps the reservoir sit as a more compact load. A baffled reservoir further limits water movement.

Not necessarily.

Refilling while the reservoir remains in the pack can be quicker and avoids disturbing carefully packed clothing and equipment. The disadvantage is that you will normally need to manage the refill yourself.

A tightly packed compartment can also compress the reservoir, so it may appear full before it actually contains its normal capacity. Bear this in mind if you need enough water for a long section.

Removing the reservoir takes more time and can disturb the contents of the pack, but it makes filling easier and allows an aid-station volunteer to refill it while you deal with food, clothing or another task.

A quick-disconnect system lets you remove the reservoir while leaving the drinking tube routed through the pack. This makes removal and refitting much easier, particularly when the rear compartment is already tightly packed.

It also allows the reservoir and hose to be separated for cleaning and drying. If a compatible hydration system does not already provide a convenient disconnect point, an inline connector can add a push-button quick disconnect within the drinking tube.

For normal conditions, a standard drinking tube is the simplest and lightest option.

For hot weather, an insulated hot-weather tube reduces heat transfer and helps keep water sitting in the exposed hose cooler.

For freezing conditions, a cold-weather tube uses additional insulation around the tube, valve and connection to help prevent ice from forming and blocking water flow.

Choose insulation because the conditions justify it. Standard tubing is lighter and less bulky when temperature control is not needed.

A bite valve should provide good water flow without requiring excessive effort. This becomes increasingly important when you are fatigued.

A positive shut-off is useful for preventing accidental dripping or water loss when the reservoir is not being used.

Route the tube securely so the valve is easy to find by feel and does not swing or tap against the vest. Many packs provide loops on either shoulder strap, while a clip or magnet can provide additional retention. Over-the-shoulder routing can also help keep excess tube controlled and easy to stow.

Rinse hydration equipment after use and follow the manufacturer's cleaning instructions. A wide opening makes reservoirs easier to wash, while reversible reservoirs can be turned inside out so the internal surfaces are easier to reach and dry thoroughly.

The drinking tube and bite valve also need cleaning. Residue can remain inside narrow tubes and around valves even when the reservoir itself looks clean.

A dedicated cleaning kit with a long flexible tube brush and a larger brush can reach drinking tubes, reservoirs, bottles, soft flasks, caps and other areas that are difficult to clean thoroughly with a normal brush.

After cleaning, rinse everything thoroughly and allow each component to dry completely before reassembly and storage.

Electrolyte and carbohydrate mixes can leave residue behind in the reservoir, tube and valve. If this is allowed to remain, it can contribute to staining, unwanted smells and the damp, dirty conditions in which mould can develop.

Regular cleaning and complete drying therefore become more important when anything other than plain water is carried.

Some runners prefer to keep plain water in the rear reservoir and use front soft flasks for electrolyte or carbohydrate drinks partly for this reason.

Do not leave drink residue sitting inside the system after use. Rinse it, clean it when required and allow the reservoir, tube, valve and other components to dry completely before storage.

Reversible reservoirs make drying considerably easier. Check bite valves, connectors and tubes periodically for wear, damage or persistent contamination.

Replacing an individual worn component can keep the rest of the hydration system in service for considerably longer.

Not if the affected component can be replaced and the reservoir itself remains in good condition.

Bite valves, drinking tubes, quick-disconnect components and other parts can often be replaced individually. This avoids discarding an otherwise serviceable reservoir.

Replacement can also be an opportunity to improve the existing system. A locking bite valve, quick disconnect, insulated tube or better hose retention may solve a specific problem without replacing the reservoir itself.