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Reviews > Water Treatment > Filters > Platypus GravityWorks Carbon Element > Owner Review by Ray Estrella

Platypus GravityWorks Carbon Element
By Raymond Estrella

July 12, 2014


NAME: Raymond Estrella
EMAIL: rayestrellaAThotmailDOTcom
AGE: 53
LOCATION: North Western Minnesota, USA
HEIGHT: 6' 3" (1.91 m)
WEIGHT: 213 lb (96.60 kg)

I've been backpacking for over 30 years, all over California, Minnesota, and many western states. I hike year-round in all weather, and average 500+ miles (800+ km) per year. I make a point of using lightweight gear, and smaller volume packs. Doubting I can ever be truly ultralight, I try to be as light as I can yet still be comfortable. I start early and hike hard so as to enjoy the afternoons exploring/chilling. I usually take a freestanding tent and enjoy hot evening meals. If not hiking solo I am usually with my brother-in-law Dave or my twin children.

The Product

Manufacturer: PlatypusCarbon Element, the Last Airbender
Web site:
Product: GravityWorks Carbon Element
Year manufactured: 2013
MSRP: US $12.95
Listed weight: 1.16 oz (33 g)
Actual total weight: 0.88 oz (25 g)
Dimensions listed: 1.25 x 2.25 in (32 x 57 mm)
Dimensions verified accurate
Picture at right courtesy Cascade Designs

Quick & Dirty, Nitty Gritty

The Platypus GravityWorks Carbon Element is a quick and inexpensive way to make backcountry water taste better. Adding a little weight to make pond water non-gaggy is a winner in my book. Plus it reminds me of Aang, the Last Airbender… Please read on for the details.

Product Description

The Platypus GravityWorks Carbon Element (hereafter referred to as the Carbon Element) is simply a tiny post-filter that contains what is called activated carbon (or activated charcoal, same thing). What makes the carbon be called "activated" is that it has been processed with oxygen to create millions of tiny pores between the carbon atoms. This increases the surface area of the carbon threefold. Here's some fun that my daughter (the Math-lete) and I had, without boring you with the in-betweens. One ounce of activated carbon has a surface area of 21,600 sq ft (2007 sq m). My guess is that the Carbon Element contains by weight at least 14 g (0.49 oz) of activated carbon. (Figuring that even after processing the carbon weighs more than the ABS plastic that the Carbon Element's shell is made of.) This would give the filter 10,584 sq ft (983 sq m) of surface area to filter through. That's a bit larger than a quarter of an American football field. All inside a tiny cylinder…

Tiny filter having a ball

Like I mentioned before the Carbon Element is made of ABS injection molded plastic. The carbon, which is the granulated type (it is made in powdered form also, but is for more stringent, and lesser lived uses typically), is packed inside the plastic cylinder. The cylinder is also packed with foam to keep the carbon granules in place, keeping it from developing channels.

The filter has two hose barbs at each end, centered in the cylinder. As both come out of the center this tells me that the activated carbon is in a mass above the outflow barb. Water simply flows down through the foam and activated carbon and out to continue its journey to my water vessel. (This is why I also guess at granulated carbon as powdered would most likely be formed into an interior cylinder in an application like this, which would then need one of the inflow/outflow points to be on the side.)

To keep things simple the Carbon Element has a big blue arrow with the word FLOW running down the side. Stick the water filter's outflow tube into the included extension hose and then into base of the blue arrow end, and the water vessel (bottle, hydration tube, etc.) on the barb at the pointy end of the arrow and we are ready for action.

Field Data

Sitting on table

I used the GravityWorks Carbon Element on all of my 3-season hikes in 2013, and a few this year. All use was in the State of Minnesota (MN) including numerous backpacking trips to the Halstad/Hendrum areas on the Red and the Wild Rice Rivers on my side of the state (west), plus trips to Itasca State Park, Chippewa National Forest and Paul Bunyan State Forest (like in the pic above where it is on the table) for at least 27 days. Temps encountered ran from lows of 32 F to highs of 80 F (0 to 27 C) with a lot of rain, some hail and even snow once.

But the best trip I had it on was a backpacking trip with the kids on the North Country and Halverson Trails. You can see it in the background at our camp on Halverson Lake. And look at that great tasting water on the table. (Take our word on it.)

The kids wanted to be in every review...


I drink a lot of water. (Don't we all? Well, I hope we all do…) When backpacking I try to average three L/qt of water a day while hiking, plus another two in camp and during the night. Having said water taste good is pretty important. If the water tastes like crud, it makes it hard to choke down my allotted amounts.

I spent most of my life and hiking career in the mountains of California where the water is pretty tasty as a rule. But high elevation shallow lakes and tarns can get pretty green at the end of summer. And glacial fed creeks with it milky water can get pretty weird-tasting at times from all the minerals ground up over eons and deposited in the melt. But that is nothing compared to the water I see in my new digs, Northern Minnesota and the surrounding areas. They don't call it the land of 10,000 mosquito breeding sources (lakes) for nothing. All those lakes (of which there are actually over 15,000 lake-sized bodies of water) are scattered across a pretty flat state. This means that the lakes get warm in the summer which leads to lots of algae growth and water that tastes like somebody left the salad bar in the backyard after the 4th of July party.
Making water tasty, one bag at a time
As many know I have pretty much switched to water filters that are based on hollow core technology, and use those as gravity filters for the most part. While I love the tech and the great job it does on getting rid of nasties quickly and with a lot of effort and weight, it does nothing to improve the taste of the water that goes through them. Now let's make things worse. Often times I am forced to get water from beaver ponds. In fact one official camp on the Superior Hiking Trail (SHT) is named "Beaver Pond". Guess where the SHT'ers (I love that acronym…) get their water from? Beaver ponds are like little shallow lakes that not only have algae, they have everything Mr. and Mrs. Beaver and their kids leave in it. ("Ward, is Beaver OK? Look what he just did in the pond" ;-) It does add a special taste. Yeah, just like the Sierra Nevada creeks that are downhill of major cattle grazing areas I get water that, while safe, is still carrying a bit of grunge. (And maybe it is in my head, but still.) What to do, what to do?

Enter the charcoal filter. Or in my case, the Platypus GravityWorks Carbon Element post-filter. This tiny little addition to my regular filter system removes the off tastes from my drinking water. And it really can't be any easier to implement. I just stick the included silicone extension hose onto the outflow end of my filter and then plug in the inflow end of the Carbon Element as seen to the right.

It works great. For the most part I have used it in conjunction with the Platypus GravityWorks 2.0L Pump-free Microfilter system, but I used it with another gravity filter system I made myself from three different companies' parts. With both systems the Carbon Element has worked great at giving the kids and me great tasting water.

Work away CE

Half of my trips with the Carbon Element have been to at least the center of the state where the lakes I stay on are deep enough to be pretty good as long as I swim out to do my collecting. So on these trip the Carbon Element is just making it better tasting, not saving the day. But if I have to get water from rivers, like the shallow and green Shell River (center state) or the dirt-infused Wild Rice or Red Rivers (west side) then I really need the Carbon Element to make the water taste better. In the picture above the Carbon Element may be seen working on some fairly nice water from either McCarty or Halverson Lake. In the other is some of our nasty water from the Red River of the North. The Red is full of dirt in suspension and has a noticeable mineral taste when filtered straight through a hollow core system. The Carbon Element makes them both taste pretty much the same.

Since I spent nine years hiking with a gram counting UL'er (hi Dave) I figured I would weigh the Carbon Element when it was just used. On my last trip I just drained it and then wrapped it up and headed home. Once home I then shook it out, whipping it like I would in camp, to fling the water out as best I could without turning it into an aerobic exercise session. The wet weight that is now carried comes in at 1.34 oz (38 g). Not too bad in my opinion for water that I don't have to mask with powdered drink. (Yeah that is my disguise of choice.) I just used it this weekend (July 6, 7, 2014) and it is still working well. Once it dies (which the company estimates at 300 L depending on water quality) I will certainly get another one. While I am not yet to Dave's UL standards I still try to cut weight as much as possible and the Carbon Element is a pretty lightweight option for better water. I leave with a picture at one of the central lakes filling a bottle directly from the Carbon Element.

Bottle time

This report was created with the Report Writer Version 1.5 Copyright 2014. All rights reserved.

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