I've had the Cat Mate Pet Fountain for almost a year now and I love it. My cat won't drink from anything else. It is much easier to keep clean than the PetMate Fresh Flow model it replaced. One of my favorite features is that the water goes through the filter before it goes through the pump. Ya think?
My least favorite feature is the filter itself. It's a blue plastic cartridge filled with carbon gravel and layers of polyester-type filter. It works great, but needs cleaned about once a week to keep the slime away. The main problem with the filter is that when you need a new one, you have to replace the entire plastic assembly! What an unnecessarily wasteful expense.
I tried squeezing my leftover PetMate filters into the plastic case until I ran out of them. Then I Googled in vain for a filter hack. I found a few discontinued products people had tried, but that wasn't going to help me.
At some point in my search I came across aquarium and pond filter supplies. It was worth a risk. These seemed to be the same basic materials, designed to keep water clean enough to keep fish alive: It ought to be good enough for my cat.
Amazingly, I hit the jackpot on my first trial! I ordered cut-to-fit polyester and carbon filter pads from Amazon.com, thinking I'd find a way to squeeze them into the leftover blue cartridge. The carbon sheet is actually much thicker and more rigid than I expected, and can be used without the plastic case! Because it's cut-to-fit, this should work for a wide variety of pet fountains.
How to make filters for pet drinking fountains
How to make filters for pet drinking fountains
empty Cat Mate filter cartridge
rotary cutter and self-healing mat
straight edge
scissors
Fold the polyester pad in half lengthwise, or as we teachers say, "hot dog" style. Use the empty cartridge to measure and mark a strip the width of the filter. Cut through both layers with your rotary cutter. Measure and mark the lengths, and cut.
Use a couple of the polyester pieces to measure a strip of the carbon fiber. This material is much thicker than the rotary cutter blade, so it didn't cut all the way through. I finished the job with my scissors.
Layer one white pad on top of the black filter and place in the cartridge slot. It fits perfectly and holds itself in place. During my first weekly cleaning, I noticed the polyester pad was sagging a bit and there was a lot of black sand in the water. I decided to sandwich the charcoal with another layer of polyester and bind all three together with a rubber band.
The polyester pad is machine washable and can even be bleached if you then treat it with a dechlorinator. Most manufacturers recommend using vinegar to clean pet fountains and cycle through your pump.
And there we have yet another amazing use for vinegar! Can I buy stock in the stuff?
Update: I noticed the filter was working so well, by the time it needed cleaning, the pump was actually struggling to find water. I think I'll take out the second layer of polyester after all. It'd be better to let a little gunk go through the pump than burn it up completely.