I think they stopped making them probably for 1.)They cost too much too produce and profits would be small 2.)Every aquarist has turned to biological cleaning obtained with slower output filters. If you notice the filter housing has an extended lip running its length. It's behind the return tube (goes to the motor shaft). This lip rests on the top edge of your aquarium so that the top of the filter housing will be at the top of your tank. You should have seperate intake tubes.They aren't shown in the picture. First put your carbon if used, and floss in the filter. Fill the housing with water about 2 inches from the top. Place the filter on the outside back of the tank resting on the edge. Now the intake tubes have to be primed manually,that is filled with water,no air.To do this,take one at a time,submerge it in the tank until all the air is out,completely filled with water. Place your thumb( tight) over the opening at the curved end not letting air in.Keep the other end submerged. Place the curved end into the filter water then release your thumb.It should be filled with water with no air. Some filters came with a little cup attached to a stick to replace using your thumb. Don't know if you have this device.Repeat the priming for as many intake tubes you have. Now you are ready to start the filter. Are the filter housings for each filter the same size? Does each motor list the same rpm's ? I 'm not sure of the ratings for your filters. I used similar filters on a 75 gallon and a 55 gallon. Water was always crystal clear. Note if these motors have thin horizontal tubes running to the top and bottom bearings they need to be oiled regularly.