What about using something like K1 in there? I have a bunch of that I'm not using right now.
Again, im still learning about this, so im only speaking from what I learned through research and watching/learning from some experienced aquarists.
I think it K1 media should work. It'll provide a physical substance to break apart the bubbles, and also provide additional bio filtration. I've seen people put in those bio-balls, so it doesn't seem to me that what you put in there is super important.
The reason I'm gonna be using sponge and lava rock is not because I think it's superior, but because it's what I have on hand and don't have to buy extra. And lava rock for me was less than $5 for 50lbs at Homedepot. So I bought two bags.
I used up 1 bag already cayse I used about 60% in my scape to put under the substrate (to help prevent ammonia pockets from top thick of a substrate level, and also extra bio-filtration cause it's heavily porous so lots of surface area for beneficial bacteria to grow). The remaining 40% of the first bag i put into different tanks in mesh/netted bags so that I can jump start my 125 and make the cycling period shorter. I'll just put the bags of lava rock in th3 sump and then pour in loose lava rock (from the 2nd bag) to fill in the remaining space.
Sorry, I went a little off topic, but to come back around, in my inexperienced yet researched opinion, I think K1 would work great.
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