One of my friends just gave me a bunch of LR that he got from TBS. However it has a lot of red algae and other stuff on it that I don't want in my tank. I was thinking if i sun dried it would I have to re-cure it or could i just dump it in my tank?
I have my "old" rock in a container w/bleach, then I'm going to scrub it/sun dry it. If you simply let it die off, without cleaning the dead stuff off, then you will have a cycle when the dead stuff goes in your tank.
If there isn't anything on the rock, then no cycle
Ever feel like you are repeating yourself again and again?
I've reused rock MANY times. The safest way to do it is as Moe suggests. 1 gallon water to a cup or so of bleach. This will dissolve most of the proteinaceous substances on the rock. That way what you kill will not later dissolve and be adding nutrients to your tank. Leave it in the bleach for a week, rinse well, then put it out in the sun to dry for a few weeks until it no longer smells of bleach. In the winter I put it on top of my oil burner to help vaporize the bleach. You can also neutralize the bleach with some sodium thiosulfate (if you have some handy!), but I'd still probably let the rock dry before using it.
Also, check out the thread where we discussed this not long ago.