A few weeks (months?) back I paid some attention to Bichir Girl's indoor goldfish pond and found the fish to be much bigger than I remembered them to be! This is the only tank that is not in the fish room currently and is the "cat tank". Well, I'd been slowly pulling the pieces together to upgrade this tank and time caught up with me in the form of one of the fish dying. So, I sprung into action this past weekend and did the upgrade... and today I finally have some time to play on the internet and update this thread!
Before (29g):
After (60g):
I built the top out of twin-wall poly and ran two air lines through the top and downstairs into the fish room. This tank is on the main floor directly above the fish room, so I didn't have to go too far. And the previous home owners had already cut a whole in the floor for me to run the cable for a TV
Because this tank is above our fish room, it is above our central air pump, so I needed to put a check-valve between the air manifold and the upstairs tank. I considered many options for this, but in the end I settled on the design below:
When I originally installed the air lines for the central air system I put in a slip x slip x thread T at the farthest point from the air pump and then plugged it a threaded plug. I did this so that I could coax debris through the system if I needed to in the future. BUT, it's also a convenient place for tying in the air-lines from upstairs, so that's what I did. The union allows me to unscrew this assembly from the main system (see space constraints below). I used a spring check valve because any water coming down from the upstairs tank will be at a trickle relative to what would be coming back from a sump and I didn't want to take the chance that a swing check would not be activated and/or seal well. Here it is installed: