Platypus Big Zip EVO 3L Reservoir vs HydraPak Velocity 3L Reservoir

The Big Zip EVO opens across the entire top, holds itself open on a stiff baffle, and lets the hose off at a high mount so you are not fighting a full bag over the sink. The Velocity 3L costs less, weighs less, and answers the drying problem a different way by turning inside out and going in the dishwasher.

Platypus Big Zip EVO 3L Reservoir

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The most cleanable design here, with a full-width slide seal, a baffle that keeps the walls apart while it dries, and a hose that comes off high on the bag.

• The SlideLock closure slides both directions to open the entire top, so a hand and a towel both fit inside.
• Platypus lists a high-mount quick-disconnect plus a leak-proof shut-off valve, so the hose separates without draining the reservoir.
• Platypus states the materials are certified taste-free and free of BPA, BPS and phthalates, and the 3L is made in the USA of US and imported materials.

• Platypus markets embedded silver ion as protecting clean water from mould and bacteria, which is a bigger claim than a plastic additive can carry on its own.
• Platypus tells you to periodically rub petroleum jelly into the zipper tracks when they get stiff, which is a maintenance chore the screw-cap designs do not have.
• The care guidance is hand washing with warm soapy water plus their own cleaning kit for tough spots, so no dishwasher shortcut.

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HydraPak Velocity 3L Reservoir

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The lightest way to solve the drying problem, because HydraPak says you can turn it fully inside out and put it on the dishwasher's top shelf.

• HydraPak's own cleaning guide says its reservoirs are reversible for scrubbing and dishwasher safe on the top shelf when fully reversed.
• The Slide-Seal top opens extra wide for filling and ice, and the reservoir dries in the inside-out position.
• The Plug-N-Play connector has a leakproof auto-shutoff, so the tube comes off a full bag and insulated tubes or filters go on in its place.

• At a stated 137 g it is the minimalist option, with no baffle or backer plate to keep the profile flat when loaded.
• HydraPak lists BPA and PVC free on the tougher Force reservoir but does not carry that statement onto the Velocity page.
• The Comet bite valve has to be pulled apart into sheath, post and on/off body to be cleaned properly, which is fiddly the first few times.

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Side by side

The bottom line

Our overall pick is the Platypus Big Zip EVO 3L Reservoir - The most cleanable design here, with a full-width slide seal, a baffle that keeps the walls apart while it dries, and a hose that comes off high on the bag. Choose the HydraPak Velocity 3L Reservoir instead if hikers, riders and runners who want the lowest-effort cleaning routine and do not mind a bare-bones bag.

Want the full picture, including the other options we compared and the popular one we'd skip? Read the complete The Best Hydration Bladders: 4 Compared (and One to Skip).