Well I made sure I had everything that I thought I needed; 30 gallon tank for sump, new skimmer (in sump type) with rated pump, return pump rated for the overflow; plus the overflow and pvc pipe with unions elbows etc. Then I made sure I had enough containers to hold my LR, sand, fish, and corals. By the time I filled the containers with tank water and sand, the old 55 was empty. I then moved it out of the way and moved in the 125 stand. You will probably have to remove one of the "back" support braces to get your sump in. This I did. I set the sump, skimmer, return pump with pvc, overflow with drain pvc . Then I set up the aqua lifter pump on the overflow.
I began by putting all the old Live sand in the new tank, added new sand to make a 4" sand bed. Then placed the live rock in where I thought I wanted it, (I've since moved it several different times). filled with new made up salt water about 1/2 full. The started adding the old water until the tank was full right to the edge of the overflow intake. I then followed the instructions on filling just the first half of the overflow and begain adding more water to the tank to get water into the sump. Once the sump was about 1/2 full I started the return pump. BTW I had more ready made salt water to add to the sump for when I turned on the return pump. Everything was going great! I let the sump run for about 30 minutes with all pumps running. I did use some more of the new water to bring the sump to right at 3/4 full. I then shut off the water to test the sump and backflow. BUT before you do this; MAKE SURE YOU HAVE A SIPON BREAK HOLE DRILLED INTO YOUR RETURN LINE ABOUT 2" BELOW THE HIGHEST LEVEL OF TANK WATER! Once off the water backflowed into the sump and stopped once the sipon hole was exposed to air. The test worked perfectly! the sump filled to within 1 1/2 - 2" from the top! I tried repeated test to make sure it wouldn't flood. I let everything run for a few hours to even out the flow, temp, and setlle. Note: with the aqua lifter pump on the overflow; all I had to do was to hit power supply switch to turn everything back on. The aqua lifter pump worked as planned and everything started flowing as before! I then acclamted the corals and fish to the new tank and everything went great. No mini cycle all fish and coral made it fine! Just make sure you use your old LR and most of the Live sand; cept for the really dirty bottom most sand. You should be fine. GOOD LUCK!
