Best Hydration Bladder 2021
In this Guide
- 1 Types of hydration bladders:
- 2 Classification of hydration bladders
- 3 Hydration Bladder Essentials:
- 4 Top 10 Hydration Bladders of 2021
- 5 Best water bladder for backpacking
- 6 Best water bladder for hiking
- 7 Best water bladder for camping
- 8 Best hydration bladder for running
- 9 Best hydration bladder for skiing
- 10 Best hydration bladder for mountain biking
- 11 Best hydration pack without a sweaty back
- 12 Frequently Asked Questions (FAQS)
Hydration Bladders are essential for recreational activities such as hiking, skiing, and cycling. They are a convenient alternative to water bottles, as they are specifically designed to transport and drink water efficiently while engaging in any outdoor activity. For most hydration bladders you don’t need to stop what you’re doing to drink water.
Even though hydration bladders are harder to refill and clean, they make staying hydrated easier. All you have to do is grab the tube and bite down on it, making it easier to get 1 liter of water every 2 hours. Hydration bladders available in 1.5 liter, 2 liter, and 3-liter variations; supporting up to 6 hours of hiking, thus they are less likely to run out of water. A 3-liter hydration bladder is equivalent to 6 bottles of water!
Moreover, hydration bladders make it easier to carry water as the weight is spread evenly across your back, so less pressure on your lower back, hence reduced lower back and knee pain. 1 liter of water is approximately equal to 2.2 lbs and the average hiker carries 8 liters of water, making water one-third of the total gear weight. Ideally, the sleep system, tent, and pack should weigh less than 8 lbs all together. A heavy backpack centers the weight on the lumbar region instead of the core, causing back pains and in some cases knee injury. This not only slows you down but makes it harder to navigate through difficult terrains. In difficult terrains, the heaviest items need to be close to your body, in order to maintain balance. Water bottles make this impossible as most hikers keep the bottles outside the pack, off throwing their balance. On the other hand, hydration bladders spread the weight evenly across your lower back, which not only helps in reducing pain but also helps in maintaining balance.
Types of hydration bladders:
Hydration bladders can be divided into two broad categories:
Pressurized hydration bladders
Pressurized hydration bladders consist of two chambers- one for air and the other for water. The built-in air pump helps in inflating the air chamber until it is fully-bloated. It eliminates the need to suck in order to drink water, all you have to do is bite or squeeze the valve for water to come out efficiently.
Even though pressurized hydration bladders are more expensive than non-pressurized hydration bladders, the benefits outweigh the costs. Pressurized bladders have multiple uses, within and outside outdoor expeditions. They can be used to water plants, wash dishes, and even take a quick shower! They are also relatively cleaner than non-pressurized hydration bladders as they aren’t susceptible to bacteria and mold build-up. However, if you use them for sugary or sports drinks, it is recommended that you flush them with a lot of water.
Non-pressurized hydration bladders
Non-pressurized hydration bladders only have one chamber to hold water. They are rather simple to use as the user needs to bite the valve and suck in order to bring the water up. They are easily available in shops and online at affordable prices.
Unlike pressurized hydration bladders non-pressurized hydration bladders require frequent cleaning as they are more vulnerable to clogging and backflow.
Classification of hydration bladders
There are 5 further classifications of hydration bladders:
Type of opening
The type of opening determines how difficult or easy it is to open the bladder and how leakage prone the bladder is. Bladder opening can be divided into 3 categories:
Fold-Top opening:Pros:
- Guarantees no leakage
- Easy to fill
- Easy to clean
- Mainly used on expeditions near water bodies
Screw-cap opening:
Pros:
- Can be filled to the brim
- Is efficient for long hiking trips and running
Cons:
- Difficult to open and close
- Requires a cleaning kit
Zip-top opening:
Pros:
- very easy to open
- Not susceptible to leakages
- Best for slow-moving water sources and faucets
Cons:
- Difficult to clean
Size of bite valve:
The size of the bite valve helps in determining the water flow and water pressure from the bladder. Bite valves are available in 3 sizes: small, medium, and large. The smaller the valve, the less the water you get, and the harder it is to suck water.
Medium-sized valves are most efficient, as they are easy to suck water from and provide sufficient water flow as well. Runners mostly prefer medium-sized valves.
Material:
The type of material determines the durability and weight of the hydration bladder. The table below describes the material used to make hydration bladders:
Polyurethane | Polyethylene |
---|---|
Strong and durable | Strong and durable |
Less flexible | More flexible |
Water may have a plastic-like taste | Plastic taste-free |
Example: Camelbak hydration bladders | Example: Source Tactical WXP and Deuter Streamer |
Capacity:
Hydration bladder capacities range from 0.5 liters to 10 liters. The smaller the bladder, the easier it is to carry, and the lighter it weighs.
The most commonly used hydration bladders are 2-liter bladders. These medium-sized bladders are enough to last 1 day and are commonly used during cycling, skiing, running, snowboarding, and hiking. For camping trips, 4-6 liters are ideal as it lasts a couple of days, so you don’t need to rush to a nearby pond or stream every time you need water.
Valve locking mechanism:
Valve locks are responsible for preventing leakages and efficiently allowing the entry of water.
There are 3 types of valve locking systems:
Switch valve-locking mechanism:
- Not susceptible to jams
- Easy to clean
Turn twist valve-locking mechanism:
- Easy to operate and clean
Push & pull valve-locking mechanism:
- Very reliable
- Easy to use
- Relatively harder to clean
Type of Hose:
The type of hose is dependent on the weather and essential for cleaning.
There are 2 different types available:
Clear/opaque:
Pros:
- Easily see through the interior so clogs and dirt is visible
- Easier to wash
- Perfect for moderate weather
- Available in a range of colors
Cons:
- Time-consuming to wash
- With opaque hoses, it is difficult to spot dirt
Insulated/non-insulated:
Cons:
- The water will tend to freeze in the winters and heat up in the summers if they aren’t insulated
Hydration Bladder Essentials:
When shopping for hydration bladders it is necessary to keep in mind the following:
Fit
The pack won’t be wearable if it doesn’t fit well. Some companies sell their packs in different sizes- Salomon Advanced Skin S-Lab is available in 5 different sizes. The sternum straps are adjustable at the shoulders for most hydration packs, making it custom fit. Nathan VaporShape and Nathan Intensity 2L produce women-specific hydration packs as well.
Hydration Capacity
Hydration needs will depend upon the intensity and duration of the activity. For minimum water needs a 2 liter hydration bladder, like the Nathan HPL #028 Race Vest will suffice, otherwise, the 3 liter hydration bladder will be perfect.
Weight
The hydration bladder should be lightweight and ideally less than 9 ounces.
Durability
The water reservoir itself does not cause leakages, however, the joints such as the mouthpiece may leak. Consequently, the durability of the hydration bladder depends on joint quality. Preferably, the hydration bladder should have a detachable mouthpiece, which can be replaced when it’s worn out to prevent leakages.
Closure type
Wide closures are ideal for hydration bladders. They allow your hand to fit in the hydration bladder and clean it easily.
Mouthpiece
Bite valves are the most hassle-free valves available for hydration bladders. They allow for hassle-free access to water-all you need to do is apply pressure on the mouthpiece to open and provide water.
Accessories
Additional accessories that go with the hydration bladder include tubes with water fillers, magnetic clips for mouthpieces, tube insulators for cold weather, cleaning kits, and flow meters.
Top 10 Hydration Bladders of 2021
To make your selection of hydration bladders easier, here is a review of some of the best hydration bladders available in the market. Please note that all the products stated below follow the essential requirements for a hydration bladder as mentioned above.
1. Source Outdoor Widepac 3l
Check Source Outdoor 3l on Amazon
Rating:
5/5
Suitable for:
- Hiking
- Trekking
- Mountaineering
- Backpacking
Key Features:
- Weight: 6.3 oz
- Liquid capacity: 3 liters
- Material: Polyethylene
- Dimensions: 8.5 x 16.7 inches
- BPA free: Yes
- Mouthpiece: Bite valve
- Closure Type: Wide Slide closure
- Detachable Tube: Yes
- Other Capacities: 1.5 liters, 2 liters
- Accessories available: tube with swyer water filter, cleaning kit, magnetic mouthpiece, tube insulator, universal tube
Available in multiple sizes:
Available in 3 different sizes, the Source Wideplac hydration bladder is available in 3 different sizes of 1.5, 2, and 3 liters and is extremely popular amongst hikers, bikers, and mountaineers due to its simplicity and durability.
Durable Material:
The bladder is made up of 3 layers of polyethylene and treated with antimicrobial to stop the growth of bacteria. The reservoir and tube are made up of a glass-like material, making it easy to clean. The wide slide closure allows for easy refilling, draining, and cleaning. The tube is detachable and the bite valve mouthpiece made of silicone features a safety shutoff mechanism, preventing leakages. The dirt shield protects the bite valve from any form of contamination.
Pros | Cons |
---|---|
Durability and easy maintenance | The suction valve is a bit too big in size |
Free from BPA, BPS, and phthalates | |
Leakage free | |
Detachable tube | |
No odors or tastes added to water | |
Water is kept sterile and contamination-free |
Deuter Streamer 2.0 Hydration Bladder
Check Deuter Streamer 2.0 on Amazon
Rating:
4.5/5
Suitable for:
- Hiking
Key Features:
- Weight: 5.50oz
- Liquid capacity: 2 liters, 3 liters
- Material: polyethylene
- Dimensions: 35 x 19 cm
- BPA free: yes
- Mouthpiece: twist-to-lock valve
- Closure type: fold- top closure
- Detachable Tube: No
- Other Capacities: not available
- Accessories available: none
Leakage Free:
The hiker’s top pick, Deuter Streamer 2.0 is available in sizes of 2 liters or 3 liters and is made up of polyethylene. The hose is connected at the base of the bladder, allowing for a quick odorless flow of water. The twist-to-lock valve ensures that the hydration bladder is leakage and contamination-free. The valve only opens when you want to drink water, hence the water is kept sterile. The Fold-top closure mechanism allows for it to open widely, making it easier to clean and dry. The mesh back also helps in reducing sweat.
Pros | Cons |
---|---|
No odors in the water | Cumbersome as they bite valve needs to be opened every time you need to drink water |
Easy to use and clean | |
Durable | |
Leakproof | |
Works with even small quantities of water Good ventilation- back doesn’t get very sweaty |
Gregory Mountain Hydration Bladder
Check Gregory Mountain on Amazon
Rating:
5/5
Suitable for:
- Hiking
- Mountain biking
- Biking
- Backpacking
Key Features:
- Weight: 6 oz
- Liquid capacity: 2 liters, 3 liters
- Material: Metallocene polyethylene
- Dimensions: 17.25 x 7 inches
- BPA free: yes
- Mouthpiece: switch type bite valve
- Closure type: lock and go
- Detachable Tube: No
- Other Capacities: not available
- Accessories available: Gregory Hydration backpacks
Multiple sizes:
The Gregory Hydro reservoir is amongst the best hydration bladders available. It comes in sizes of 2 and 3 liters and is made of high-quality BPA-free, Metallocene polyethylene, making it extremely durable. The inner surface of this hydration bladder is treated with antimicrobial agents to prevent the growth of mold and bacteria.
Versatile design:
A special feature of this bladder is its 3-D design, making it resemble a water bottle- only softer. Due to its 3D design, the two surfaces are separated, preventing water from getting trapped and making it easier to clean. It also allows for the bladder to be relatively flexible, sitting against your back while you’re on an outdoor expedition!
Leakage free:
The switch-type bite valve makes it very easy to operate- just push it using your thumb for the water to flow. It is also leakage-proof. The rubberized surface makes it easy to grip and allows for easy and quick refilling.
It is also compatible with the Gregory Hydration and CamelMule backpacks.
Pros | Cons |
---|---|
No tastes and odors in the water | Seams need special cleaning kits |
Speedy drying | The mouthpiece doesn’t have a dust cover |
Easy to grip and refill | |
Can be easily attached and detached from the backpack | |
No slashing of water |
Platypus Big Zip Water Reservoir
Check Platypus Big Zip on Amazon
Rating:
4.5/5
Suitable for:
- Hiking
- Trekking
- Backpacking
- Mountaineering
Key Features:
- Weight: 6 oz
- Liquid capacity: 3 liters
- Material: Polyethylene
- Dimensions: 8.8 x 7.2 inches
- BPA free: yes
- Mouthpiece: bite valve
- Closure type: wide slide closure
- Detachable Tube: yes
- Other Capacities: 1.5 liters, 2 liters
- Accessories available: tube insulator, mouthpiece clip, Hyperflow bite valve
Available in multiple sizes:
The Platypus Big Zip water reservoir is available in 3 sizes and can easily be stashed away in your backpack. The bladder is made up of a 2 layer of Polyethylene material which prevents the water from tasting like plastic and also makes it extremely durable. It’s BPA, BPS, and Phthalate free, and is also embedded with silver ions to prevent the growth of bacteria and mold. The clear, see-through color of the bladder, allows you to manage the water intake.
Ease of Access:
The wide-slide closure allows for easy refilling, cleaning, and draining. The disconnect hose makes the reservoir flexible and helps with the cleaning process as well. The self-sealing bite valve also eliminates any chance of leaks.
Pros | Cons |
---|---|
Taste and odor-free | Hose not insulated |
Extremely durable | No color variety |
Easy to use and clean | A flimsy handle on clip side closure |
Leakproof | |
Slim and flexible |
CamelBak 100 Ounce Mil-Spec Antidote Reservoir
Rating:
4.5/5
Suitable for:
- Hiking
- Trekking
- Backpacking
- Mountaineering
Key Features:
- Weight: 8 oz
- Liquid capacity: 3 liters
- Material: Polyurethane
- Dimensions: 9 x 18 inches
- BPA free: yes
- Mouthpiece: bite valve
- Closure type: snap cap closure
- Detachable Tube: yes
- Other Capacities: 1.5 liters, 2 liters
- Accessories available: none
Affordable rates:
The CamelBak Antidote hydration bladder has seen many enhancements over the years. Available at an affordable rate, it comes with a lifetime warranty and values customer feedback. Its wide-mouth opening and large grab handles allow easy refilling and cleaning. The baseline hose connector allows for the complete draining of water.
Easy to carry:
The two water chambers make the reservoir slim and prevent the sloshing of water. The bite valve has also been changed to medium size, it is also firmer and hard to detach.
The hydration bladder is compatible with all backpacks and is lightweight as well.
Pros | Cons |
---|---|
Durable | Difficult to clean |
Easy to refill | The plastic taste may linger |
Medium-sized bite valve | Hard to fill in streams |
Compact and slim | |
Values customer feedback Good ventilation- back doesn’t get very sweaty |
Badlands Hunting Hydration Reservoir
Check Badlands Hunting on Amazon
Rating:
5/5
Suitable for:
- Hunting
Key Features:
- Weight: 5.2 oz
- Liquid capacity: 1 liter, 2 liters, 3 liters
- Material: TPU
- Dimensions: 9.5 x 6 inches
- BPA free: no
- Mouthpiece: bite valve
- Closure Type: Fold top
- Detachable Tube: Yes
- Other Capacities: none
- Accessories available: none
Comes with a lifetime warranty:
A collaboration between Hydrapak and Badlands led to the production of a hydra bladder specifically designed to meet the needs of hunters. Consequently, making it durable, leak-proof, and quieter than all other hydration bladders. It also comes with a lifetime warranty.
Dishwasher safe:
Since the bladder flips inside out, it is easy to fill, clean, and dry. Moreover, it is also dishwasher-friendly! The play and plug tube detector makes the hose attachable and detachable easily and enhances the flexibility of the bladder as well. The built-in hose insulation also keeps the water cold for longer time periods.
Pros | Cons |
---|---|
Available in different shapes and sizes | Rubbery taste present in water |
Dishwasher safe | Opaque so dirt and clogs not visible |
Easy to clean and refill | |
Comes with a lifetime warranty | |
Detachable tube |
Source Tactical WXP 3-Liter Hydration Reservoir
Check Source Tactical WXP on Amazon
Rating:
4/5
Suitable for:
- Hiking
- Trekking
- Backpacking
- Mountaineering
Key Features:
- Weight: 0.24 kg
- Liquid capacity: 2 liters, 3 liters
- Material: coextruded polyethylene
- Dimensions: 17 x 8 inches
- BPA free: yes
- Mouthpiece: push-pull valve
- Closure type: screw cap
- Detachable Tube: No
- Other Capacities: None
- Accessories available: QMT, Valve Dirt Shield Cap
Easy to use:
Like most hydration bladders, the Tactical WXP hydration bladder is also available in sizes of 2 and 3 liters but what makes it distinct is the combination of the screw cap and fold top design for opening and closing. The folding feature allows the user to clean and refill the reservoir without much hassle.
Durable:
It is also made from top-notch material- coextruded polyethylene. The glass-like lining prevents biofilm buildup which in return prevents bacterial growth and stops the plastic flavor from lingering in the water. Grunge-Guard antibacterial technology is an additional feature that prevents the growth of micro-organisms in the reservoir.
Insulated tube:
The tube is also insulated, keeping the water cold for a moderate time period. The hydration bladder is also equipped with push and pull storm technology. The pulling doesn’t allow the valve to come off, eliminating the risk of losing the valve and since the valve only opens when you need it, the water remains sterile and uncontaminated.
Pros | Cons |
---|---|
Leakproof | Large size, so hard to fit in a backpack |
High-quality construction | Hard to dry |
Self- cleaning mechanism | |
Keeps water cool for a long time | |
Easy to use |
MSR Dromedary Camping Water Bag
Rating:
4.5/5
Suitable for:
- Camping
- Hiking
- Cycling
- Backpacking
Key Features:
- Weight: 6.9 oz
- Liquid capacity: 2 liters
- Material: PU
- Dimensions: 10 x 18.3 inches
- BPA free: yes
- Mouthpiece: bite valve
- Closure type: wide slide closure
- Detachable Tube: yes
- Other Capacities: 4 liters, 6 liters, 10 liters
- Accessories available: Shower, Hydration Kits
The MSR Dromedary hydration bladder is most preferred by campers. It is available in a range of sizes, so you can buy one according to the number of people and days spent camping.
Easy to use:
The lid of the bag is wide, prevents water spillage. The wide opening allows for easy refilling and cleaning of the hydration bladder. It also comes with a detachable mouthpiece and to save space, the waterbag collapses.
Pros | Cons |
---|---|
Strong and durable | Heavy when filled with water |
Easy to store and carry | |
Different sizes available | |
Detachable tube | |
Detachable mouthpiece |
Hydrapak Velocity Hydration Water Bladders
Check Hydrapak Velocity on Amazon
Rating:
4.5/5
Suitable for:
- Trekking
- Hiking
- Mountaineering
- Backpacking
Key Features:
- Weight: 4.2 oz
- Liquid capacity: 3 liters
- Material: Thermoplastic Urethane
- Dimensions: 6.5 x 17.3 inches
- BPA free: yes
- Mouthpiece: Bite valve
- Closure type: wide slide closure
- Detachable Tube: yes
- Other Capacities: 2 liters
- Accessories available: none
Durable and safe to use:
The HydraPak Velocity hydration bladder is an upgrade to the Hydrapak Shape-Shift Reservoir. It is 100% BPA and PVC-free, so the water is free from contamination and unwanted odors. Due to the thermoplastic urethane, the water reservoir is very flexible and resistant to grease and oil. It can also be turned out, making it easy to clean and dry. Moreover, it can also be washed in a dishwasher. The center baffle holds the bladder together and prevents water from sloshing; the center baffle also makes the bladder compact and hence it can fit in any compact space.
Detachable tube:
The bladder comes with a detachable, see-through tube, as well as an automatic on-and-off mechanism for the bite valve. The valve auto seals after every sip making it leakage-proof.
Comes with a lifetime warranty:
Other striking features include a lifetime warranty and a weight of 4.2 ounces, making it the lightest bladder available in the market.
Pros | Cons |
---|---|
Reversible | Only available in one color |
Easy to clean and dry | |
Enhanced flexibility and slim design | |
Affordable price | |
Comes with a lifetime warranty Good ventilation- back doesn’t get very sweaty |
Geigerrig Pressurized Hydration Engine
Check Geigerrig Pressurized Hydration on Amazon
Rating:
4/5
Suitable for:
- Hiking
- Backpacking
Key Features:
- Weight: 6.5 oz
- Liquid capacity: 3 liters
- Material: Thermoplastic Urethane
- Dimensions: 16.75 x 7.25 inches
- BPA free: yes
- Mouthpiece: Bite valve
- Closure type: wide slide closure
- Detachable Tube: yes
- Other Capacities: 1.5 liters, 2 liters
- Accessories available: none
Versatile nature:
The Geigerrig Pressurized Hydration Engine is one of the most versatile hydration bladders available. It comes with an ellipsoidal air pump connected to the bladder’s air compartment. To drink water all you need to do is pump the bladder, filling the air compartment, and creating pressure that causes the water to squirt out. Due to the ellipsoidal air pump, the bladder has multiple uses- it can be used to wash dishes, water plants, and shower pets.
Water filter Compatible:
Another special feature embedded in this hydration bladder is that it’s compatible with Aquamira Frontier Max Water filter. To filter water, all you need to do is connect one end of the filter to the hose and the other to the bladders’ socket.
Dishwasher safe:
It is also safe to wash the Geigerrig bladder in a dishwasher and it can also be turned inside out, making it easier to clean, wash and dry.
Pros | Cons |
---|---|
Dishwasher safe | Expensive |
Has multiple uses | Damaged by extensive pumping |
Easy to fill and clean | |
Has a pressurized system | |
Slim profile |
These are some of the best hydration bladders shortlisted for 2020, which are guaranteed to facilitate in easing your outdoor expedition.
A summary of the hydration bladders is given below:
Best water bladder for backpacking
- Source outdoor Widepac 3
- Gregory Mountain Hydration Bladder
- Platypus Big Zip Water Reservoir
- CamelBak 100 Ounce Mil-Spec Antidote Reservoir
- Source Tactical WXP 3-Liter Hydration Reservoir
- MSR Dromedary Camping Water Bag
- Hydrapak Velocity Hydration Water Bladders
- Geigerrig Pressurized Hydration Engine
- Osprey Hydraulics
Best water bladder for hiking
- Source outdoor widepac 3l
- Deuter Streamer 2.0 Hydration Bladder
- Gregory Mountain Hydration Bladder
- Platypus Big Zip Water Reservoir
- CamelBak 100 Ounce Mil-Spec Antidote Reservoir
- Source Tactical WXP 3-Liter Hydration Reservoir
- MSR Dromedary Camping Water Bag
- Hydrapak Velocity Hydration Water Bladders
- Geigerrig Pressurized Hydration Engine
- Osprey Hydraulics
Best water bladder for camping
- MSR Dromedary Camping Water Bag
Best hydration bladder for running
- Source outdoor widepac 3l
- CamelBak 100 Ounce Mil-Spec Antidote Reservoir
Best hydration bladder for skiing
- Source outdoor widepac 3
- Gregory Mountain Hydration Bladder
Best hydration bladder for mountain biking
- Gregory Mountain Hydration Bladder
- MSR Dromedary Camping Water Bag
Best hydration pack without a sweaty back
- Hydrapak Velocity Hydration Water Bladders
- Deuter Streamer 2.0 Hydration Bladder
- CamelBak 100 Ounce Mil-Spec Antidote Reservoir
- Osprey Hydraulics 3l
Frequently Asked Questions (FAQS)
1) Can I transport juice or beer in my bladder?
Sure you can (in theory). Check that your bladder has an anti-microbial lining. However, if you leave Coke or other juice in the bladder without rinsing thoroughly then bacteria will grow irrespective of what lining the bladder has. The hose will become grey and murky! My personal preference is to only carry water in the bladder and if I need energy juice then I will transport it in a separate bottle.
2) How do I clean my hydration bladder?
Rinse out with warm water as soon as you can. Don’t let your energy juice get sticky. You can use soap, bicarb of soda, or lemon mixed with water to get rid of the residue taste. For more thorough cleaning use a bottle brush and thin brush to clean the hose, remove and dismantle the bite valve, and clean and rinse separately.
3) How do I store my hydration bladder?
The crux is to get the residue water out of the corners of the bladder.
Here are several little tricks that I use: Cut up an egg tray and insert it into the opening of the bladder. This lets some air get into the bladder and allows it to dry out.
Hang the bladder up above the bath to drip dry. Make sure to release the water out of the drinking tube and bite valve occasionally.
The other trick is to dry it as best you can and then pack inside your freezer compartment (with no water in the bladder). The idea is not to cool your drink but to stop bacteria from growing in it in the sub-zero freezer.
4) How do I stop the sloshing in my bladder?
Once you have filled your hydration bladder, turn it upside down and squeeze all the air out while releasing the bit valve. Now when you drink you will only get liquid and no air coming out. Also, you won’t feel the irritating sloshing when running.
5) How much water do I need to carry?
That is the million-dollar question and it really depends! According to Tim Noakes and others, the best practice seems to be to drink to thirst. For a bike ride of around 3 – 4 hours, you might need less than 750ml of water. But then you would have some catching up to do if it has been hot. However, for the first section of Skyrun, you would carry 3l as it typically takes about 5 hours to reach the first refill point. And more importantly, you are hydrating not for that section of trail but for the 20+ hours of running that you are undertaking. Practice seeing what works for you!
Hydration Bladders are great but just need a little maintenance and care to give you long service!