moving live sand?

[beattyr]

Just bought a house, and am finishing up moving into it. I still have to move my 90 gal fresh tank in, and I'm seriously considering taking it down and starting it back up as a reef. My question is I have a 37 gal reef tank thats been up 2years + now and its got quite a nice population in the sand and live rock now. How should I go about setting up this new 90 gal? Fill it up with the new sand and then toss the sand and rock from the 37 in? Or should I completely cycle the 90 1st and THEN put in the sand and rock from my current tank? Should i take care in how i move the sand from one tank to another?
Thanks for the help... now on to DIY for other questions
Rob

 

[ags]

About 6 months ago I moved my 55 into my 90. The 55 had been up and running for 2 years.
When I switched over to the 90 I bought appx. 20lbs of LS and placed it on the bottom of the 90 and then added the LS from my 55. At the same time I also added appx. 25 lbs of very cured LR (plus the 80-100lbs of LR from my 55).
My water quality did not really spike but I did two water changes the first week just to be sure. I also do weekly 10% water changes as a matter of practice so the first two weeks after the switch I performed 3 water changes. I do not remember what percentage the first two were but I am thinking 20-25%.