I recently upgraded my 55 to a 90. I got a screaming deal on the 90 from a guy who wanted desperately to get rid of it because the folks that set it up put in a tiny sump and no ATO system. He wasn't able to leave the house for more than a few hours at a time for fear that the water would evaporate too fast and ruin the main pump. Needless to say, upgrading the sump was at the top of my list when I got the tank home.
Here are some pics of the tank after I got it into my basement. Notice the 20 gallon sump, setup with a very small return chamber whose water level lowers rapidly with evaporation. Not to mentiion, this setup has no room for an RDP refugium.
So I found a 27 gallon tank on KSL, drilled it and installed some
baffles, and of course an R/O float valve (because I'm lazy and don't
like to manually top off).
One thing the installers did right was to use PVC unions on the plumbing, which made it easy for me to disassemble things, and attach my modified plumbing and a different pump.
This Velocity T4 I had on my 55 beats the Little Giant that was on the 90 for flow. It's also dead silent. You have to be a bit careful with heat when using these pumps, but I had no problem on my 55, and have none on the 90. It throws so much water that I've had a tough time finding a place in the tank with a little less flow to place my wellso.
I had to cut a new door in the stand in order to install the larger (mostly longer) sump. Also, I had to patch some cracks in the tank with a piece of acrylic and silicone. So far no leaks! The skimmer isn't my favorite, so I'll probably upgrade it sometime (when I sell more of the old tank stuff), but i have finally fine tuned the gate valve so it doesn't just fill the cup with water. Notice behind the skimmer I installed a "relief" valve on the return line in case the pump produced too much flow back into the main tank. So far I have left the valve closed.
Filling the tank. I used about 2/3 water from both tanks, and 1/3 new water.
This is my mixing/filling station.
Al the livestock and live rock went into trash cans and buckets with heaters, airstones, and powerheads. All the livestock survived the transfer well, with the sad exception of one of my clowns (but it's ok since I don't need more than 3).
Here it is full of water, rock and sand, and the pump running.
The next day I stacked the rock and added all the livestock. I love the way the rock stack turned out, and finally I have a decently deep sand bed.
The next project was to rig up the lights and put them into the canopy. I kept my 3 110W VHO's (2 actinic and 1 white) and added the 2 175W 14K halides from the original 90 setup.
Here is the final product. I ended up leaving the one white VHO unplugged since there's almost too much light with all three VHO's and the halides on.
I'll add a few more pictures (hopefully a little better) as I have time. Overall, I am pretty happy with how everything has turned out.