Filter Ideas?

I have an male Eastern Mud turtle who is about 3 inches and he doesn't like his water deeper then 4 or 5 inches. I wanted to put a small canister filter on his tank but I'm not sure his water is deep enough. What is the best filter for him?

I was also curious if there was a way for one canister filter to be set up to filter two tanks?

Thanks for any help.

I used to have a custom turtle tank I made from plate glass that measured
36"X24"X16" with a hinged top for some softshells. They liked to stay burried in fine gravel(not sand) and stretch up for air. I had a full bottom under-gravel filter/powerhead combo that worked great. Two to three inches of gravel and 4-6" water with a branch for basking(that they never used). Your mud probably won't bask much either. I was used to "vacuuming" the gravel in our fish tanks so it was simple to clean the turtles tank too. The big key with any of the aquatic turtles is to not over feed and spot clean any un-eaten food. If he pushes/digs up the gravel and exposes the filter grate, just cover it back up again. Have fun

I'm currently using a DIY trickle filter for an enclosure housing young spotted turtles.
I had never heard of anyone trying a trickle for turtles and I was curious how it would work so I constructed one. It's been working extremely well for the nearly three months I've had it in use.

Being babies, the water is very shallow, they can touch the bottom and still reach the surface to breathe anywhere they go. I didn't know of any conventional filter that would operate in water that shallow aside from an under gravel filter. Since I intended on not using a substrate for the time being, a trickle filter seemed to be the best option.

The tub they are in is a large ABS plastic tub about 5 inches deep. I put a bulkhead in the bottom on one end to act as a drain. The water gets about an inch or inch and a half deep and overflows into the drain.
The inside if the drain is threaded so I can add a standpipe and increase the water depth as they grow.
There's also a prefilter over the drain to keep large particles from getting through.

The drain leads to the filter which is a large rubbermaid tub (the sump). There's a hole cut in the lid in which sits a 3 gallon bucket.
The bottom of the bucket is completely perforated for drainage. The bucket is filled 3/4 full with bio-balls.
On top of the balls is a drip plate to distribute the water evenly and on the drip plate is a filter mat to catch anything that got past the pre filter.
Inside the sump is a pump which returns the water to the main enclosure through a spray bar made of 1.2" PVC.

The maintenance of this setup consists of siphoning out the detritus from the main tub a couple of times a week, and topping off the system with water to make up for evaporation once or twice a week.
Three months of use so far and the water remains pristine continuously and I have yet to do a complete water change, with 10 turtles in the tub.

This type of filter is really overkill but I had been wanting to build a trickle filter for a long time and this presented an opportunity for me to do so.
I've had excellent results for years using trickle filters on aquariums, and while they're not what one would normally find on a turtle tank, I've been pleased with the results.

They make several different submersible filters for this.
Here is one to consider
http://www.amazon.com/Zoo-Med-Turtle.../dp/B0002DIRP0