curing LR

[tierodking]

WHat is the proper method and ave. time to cure LR?
I have 1 20lb rock in a 5g bucket w/ 1 powerhead for about 3 weeks now and the ammonia is still at .25ppm
thanks

 

[tierodking]

bmp

 

[scoobs]

should do a half tank water change every week while curing.. been doing that?