To further fuel this discussion currently in my FX5 from top to bottom I have filter floss (walmart quilt batting), ring two (Pumice- BBQ grill scrubbers broken into inch pieces) ring three same as ring two. This same set up I use on my fluval 205 for my 29 gallon. I run zero chem and when i clean the filters I rinse tray two one month then tray 3 the following. BBQ scrubbers are 100% pumice, little dusty but a whole box of them i believe was like 10 bucks and filled one whole tray in my FX5.
But to field the question about zero oxygen zones, I would say that since pumice and matrix has pores that pass completely through it, wouldn't it require collection of debris on both sides of the pore to creat this dead zone?
29g Tetra Tank
100g Planted Angel/Clown Loach
I can't spell...Im an engineer, I do math
Last edited by VAtanks; 02-04-2013 at 06:05 PM..
Reason: My spelling is as terrible as my proof reading