ah, I saw your other post and answered it.
I'd be careful swaping it all out...I just wasn't brave enough to do that...plus I'm moving my tank soon (next weekend maybe) so I'll add the sand then.
This weekend I'll rinse the sand, and start curing it, so it'll be ready for me to add to the tank.
if you get ls, no need to rinse or cure. but I didn't have the money for 100# of ls, so I just bought sand and I'll get a cup of ls to seed the sand, plus your lr will seed the sand.
if you have fish/inverts you don't want to start a cycle.
What Agent707 said could work as well, BUT YOU MUST CLEAN/VACCUME THE CC before removing it. please trust me on this one. cc traps nasty yucky stuff, if you just net it out, the yucky stuff is released and hello major nitrates, possible recycle. (went we moved I didn't know to clean the cc, I just kept it and everything else wet....mini cycle...almost killed my two stars). Also, be careful when moving lr around, stuff gets traps in there also, esp if you don't have a good clean up crew.
YOu have to cure sand or it will clump and harden, or I was told and I don't feel like testing the infor so I'll just believe the shark. After you rinse the sand, put sand in a bucket, with water, add a bit of fish food and stir, stir once a day. this will get the good stuff growing and help prevent a cycle.
I'll be doing this soon, so I can let you know how it goes.
do decrease nitrates in the mean time, decrease feeding, increase water change, make sure you have good water flow (no dead spots), add more lr (but it'll just be a pain for you to move so you might not want to add any yet).
I would have removed all my lr one, and placed it in a bucket with heater and power head so I dind' thave to move it around so much, but I have two stars who love lr, and I don't think would like an empty tank very much.