I built a carbon filter today and figured I would make it a DIY thread. It cost me under $20 and everything is available at your local walmart. Pictures go left to right in order of the steps. Step 1: Shopping List: Lays Stax potato chips (your favorite flavor) - $1.00 Sink Drain Guard x2 - $0.97 each - Found in the plumbing section Duct Tape - $2.97 Carbon 900ml Aqua-Tech - $6.47 - Found in aquarium aisle Length of Sewer Hose - $6.44 - Found in the auto section with the RV stuff ___________________________________________________________ Grand Total: $18.82 Step 2: Eat your stax, or put them into a different container. Cut the bottom off so it looks like picture 2. Step 3: Use one of your drain guard and attach it with duct tape to one side of the stax container. Step 4: Fill with Activated Carbon. If you get the same brand I purchased it should perfectly fill it to the top with just a bit left over. Step 5: Put the other drain cover onto the remaining open end. Duct tape it just like you did on the other side. Step 6: Attach the RV sewer hose with duct tape. Again, if you purchase the same brand I did, the ends will match up almost perfectly! And thats it! You're done. Pretty easy huh?