I think calcium metal is even worse than magnesium for being touchy to handle when in powdered form. Both will burn under water. Both burn at about the same temperature. Dont they use magnesium rods as steel cutting rods underwater?

tj: What size diffusers did you get, and what psi do you have the regulator set at when using them?

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).