I am really confused about filters. I have 2, still very small RES's in a 20 gallon long tank. They seem to do best when the water level is just under the halfway point. I keep seeing recommendations for the Aquaclear 110 filter, but in the pictures I have seen of the ones for sale, it looks as if that filter is not submergible. It looks like it attaches to the rim of the tank. Am I correct? Since my water level is not even quite halfway, is this a filter I can use? My filter just stopped working, the ZooMed Turtle Clean Filter 318. I did not care for it anyway and planned to get a new one soon. I bought a new one last night on the recommendation of the sales person. Unfortunately the filter is to long and to powerful for my little turtles. I am still very new to RES care. I bougt them for my son without knowing just how much care they needed. Now I am trying to learn how to make them as happy and healthy as possible. Any help and advice would be greatly appreciated. Here is what I have in my current tank.
2 baby RES
20 Gallon long Tank
Heater set at 77
Basking area
UV Lamp
Large Rock
I am currently looking for the smooth river rocks but have been unable to find any at any of the various pet store I have in my area. Please help with the filter question, I do not want to leave them without one for a long time. Thanks!

