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- Mar 6, 2019
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If you've been running a tank with approximately 20 lbs of fake reef rock for 8 months and want to switch over to different fake reef rock, how many days would it take for the new rock to be up to speed biology wise. Note: Would be using same water and sand. Also, I am considering laying a large piece of shelf rock on top of my sand. Would I need to elevate it and leave a space between the rock and sand or can I lay it directly on the sand. It would cover about 70% of sand bottom. Thanks!