5 month old sand okay to re use?

[JerkinJohn]

I filled my 90 gallon on Dec 9th and it's been running ever since but I had an ich outbreak. Once my 12 week fallow is over ( july 1st ) I am transferring everything to a 100 gallon tank. Water, dry rock and I was thinking sand also. I did order 80lbs of new sand as well. http://www.reefrocks.net/index.php?page=shop.product_details&flypage=flexible_flypageV1_WIDE.tpl&product_id=5&category_id=1&option=com_virtuemart&Itemid=1 I am planning on re using the sand I have now and then adding some of the new since my dimensions on my 100 gal are totally different then my 90 gal. I have been reading though that re using old sand isn't a great idea and to just use new and to just seed the new with the old sand. A few scoops. However my existing sand is only 5 months old. Just want to avoid problems and would appreciate some opinions. Thanks

 

[Breadman03]

I would use the new sand since you have it, plus whatever you need of the old. I believe the big issue with "old" sand is that tons of detritus gets trapped in there over the years and gets mixed up when you move it.

I made a move from a 55 to a 75 after about that much time and had no issues using only the old sand.