hi, i just set up a 20g salt tank last night and i have a powerfilter on it as of now.thinking of gettting a powerhead soon, but as of media in the filter, i just added those porous ceramics that are long and tubular? is this okay for salt water tanks or will it lower or do something with the pH? i have this stuff in my freshwater tanks so i thought it would be okay in salt but not sure? thanks for any help.