I just finished my diy hangover filter and it has some space in it for media. I am thinking of pot scrubbers but i read that pot scrubbies works best in a wet/dry setup. I have filter mat and ceramic rings in there. I have four options in mind. Lava rocks, ceramic media, filter mat and pot scrubbies. What would be the best among the four in a submerged environment? or if you have a better idea please tell me Thank you in advance!