Well I decided on the acid bath.
I think the idea here is to strip away the very outer layer of rock which takes the organic matter and even some trace metals along with it. I don't think that I'll need to bleach them at this point. Hydrochloric acid is the same as Muriatic acid which is readily found at the local pool supply shop. I had stopped by there earlier and picked up a gallon along with a little bit of sodium bicarb.
I mixed 1:10 acid/water and let the rocks soak for 45 minutes. Though I probably could have taken them out a little sooner. When I set them in there they bubbled and boiled for about 25 minutes creating a surface layer of frothy and chunky brown stew. After 45 minutes I triple rinsed the plastic tub with tap water while the rocks were in it. Then I pulled them all out and blasted the heck out of them with the water hose getting all the nasty gunk off of them. Now I have them soaking in a solution of water and sodium bicarb with a pump thrown in for agitation. I'll let them soak for a couple of nights and then bath them in the sun for about a week. Once the tank is up I'll run some dechlorinated and carbon filtered water in it for a while and do a small series of water changes before I add the mixed water so that I can kick start the cycle before I thus begin seeding the tank.
And yes, you have to be careful with the acid. I used heavy duty neoprene gloves with goggles, respirator, long sleeve shirt and pants. I also did this outside. The hydrochloric acid is noxious and it can seriously hurt you. I used to work with a guy who got some all over his arms and some on his face and it left permanent scarring. So be careful, kiddos.,
Note: Since the acid bath virtually dissolves the rock it created some extremely sharp edges and points on some areas of the rock that are sure to be an eye gouging, fish slicing hazard . I'll have to go around on some of the rock now and do some de-burring with maybe a file or some sandpaper.
