If you are using an AC filter, you would be far better off using the AC foam inserts, perhaps 2 even, with some filter floss between the sponges. Forget the carbon, and why are you using a pH compound to regulate your pH?
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I've got to disagree on the two "factory inserts" idea. The AquaClear sponge is NOT a polishing pad. Although I am sure there are others, the only other person on this forum with HOB only that gets his water as clear as mine (that I have seen anyway) is Thumper828 and in his aquaclear, he uses a fluval sponge pre-filter and the blue backing polishing pad (which I have said in other posts is the equivalent of my 100 micron stuff) rather than a second foam insert as follows:
Aquarium Filter Media: Drs Foster and Smith Blue Bonded Filter Pad
See:
http://www.aquariumadvice.com/forums/f60/aquaclear-70-a-281447.html
and picture of his tank here along with other explanation of getting water crystal clear and polished with an Aquaclear:
http://www.aquariumadvice.com/forums/f60/aquaclear-70-a-282932.html
(those are links to two separate threads with same title)
and go here
http://www.aquariumadvice.com/forum...ion-pictures-inside-286420-4.html#post2739783
where I note at post #17:
I take all kinds of flack for only doing twice a month water changes but both my tanks are absolutely crystal clear with the "fish swimming in air" look.
The only things both thanks have in common is the 100 micron filtering pad and Purigen. [Different filters, different fish, different substrate, different brands of fake plants and rocks]
I use Seachem Matrix + aqua-tech bio-media for BB in my 38 gallon with
"Factory installed" bio-media in the Fluval on the 29 gallon.
38 gallon pre-filter is floss in a biobag.
29 gallon pre-filter is a fluval sponge.
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In the end, I'm just trying to be helpful letting people know about a "sure-fire" easy way to get truly polished "fish swimming in air" water in a community freshwater tank WITHOUT having to purchase a canister filter.