HydroBlu
HydroBlu Sidekick 3-Stage Straw Water Filter
- Protection: 6/10 What it removes from water, and how well that is proved.
- Flow rate: 1/10 How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use.
- Weight: 10/10 How much it adds to your pack.
- Ease of use: 3/10 Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean.
A back-up filter in a first-aid or survival kit that weighs almost nothing
- Type
- Straw
- Removes viruses
- No
- Flow
- 0.25 L/min
- Weight
- 57 g
- Pore size
- 0.1 µm
- Rated life
- 379 L
Where to buy
Ultralight Outdoor Gear £29.99 In stock. Free delivery. Free tracked UK delivery.
View at shop: Ultralight Outdoor GearPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Protection
From maker's figures 6/10What it removes from water, and how well that is proved. 6: A bit better than average.
A cotton pre-filter, an activated-carbon stage and a 0.1 µm hollow-fibre membrane. HydroBlu's page says 99.999% of bacteria and lists Giardia, E. coli and Cryptosporidium; the front of the pack says 99.999% of Giardia, E. coli, Cryptosporidium and protozoan cysts, and the back says up to 99.9999% of bacteria and 99.9% of protozoa. We use the lower figures; the band is the same whichever is used. No test standard or lab report is named, so this is bacteria and protozoa claimed with no published test: 3. No virus claim. The UK shop's copy says 0.02 µm and virus removal; HydroBlu's page and pack say neither, so we ignore it.
Flow rate
From maker's figures 1/10How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use. 1: A real weak point.
The back of the pack says up to 250 ml/min, which is 0.25 L/min and under the 0.6 L/min line. HydroBlu's web page gives no flow figure. Banded on the pack's figure.
Weight
From maker's figures 10/10How much it adds to your pack. 10: The best you can buy for this.
HydroBlu's page gives about 28 g in one place and about 57 g in another, and the pack gives a weight of about 28 g or less. We store the heavier, 57 g, which is well under the 90 g line; the UK shop lists 16 g.
Ease of use
Estimate from maker's specs: filter type 3/10Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean. 3: Below average. Fine for some trips, not others.
Estimate from maker's specs
In short
Good for
- A back-up filter in a first-aid or survival kit that weighs almost nothing
- Drinking straight from a stream on day walks on UK hills and moors
- Taking the edge off peaty or muddy water, thanks to the carbon stage
- Dipping into a bottle and drinking through it
Strengths
- Very light: 57 g or less, and about the size of a pen
- Three stages in one tube: cotton pre-filter, activated carbon and a 0.1 µm hollow-fibre membrane
- Carbon and pre-filter end cap is replaceable, and a spare comes in the box
- Needs no bottle, bag or pump: you drink through it
- HydroBlu's rated capacity is 379 L, and the carbon module is rated at 189 L
Weaknesses
- Slow: up to 250 ml/min on the pack, so it is for sipping, not for filling bottles
- No named test standard or lab report for the 99.999% and 99.9% claims
- Removes no viruses
- HydroBlu says not to let water freeze in it, so it is not for winter use unless kept warm
- Its own pages disagree on weight (about 28 g and about 57 g) and on bacteria removal (99.999% and 99.9999%)
- Only one UK shop found, and no independent test of this version
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.