Reddit mentions of Aquaclear A1372 50-Gallon Biomax,White

Are your trays full of biomedia? The SunSun (that I have anyway) can hold a TON of media, I wonder if you could get some more to add in and avoid this in the future. Doesn't have to be the bioballs that come with it either, I'm using something similar to this from when I was running HOBs.

HOB filters come with filter media designed specifically for them. The C4 is rated for aquariums up to 70 gallons. Usually you divide that number in half to get what the optimal tank size would be for the filter (45 in this case), so 55 gallons is okay (just don't stock it too heavily).

If your concerned and would like to add some additional filtration power, biological filtration is the way to go. Find some empty space in the filter and add something with a large amount of surface area. I use AquaClear BioMax. The large amount of surface area allows for a buildup of nitrifying bacteria that break down harmful elements produced by fish.

Sorry if I'm being too descriptive haha, but I'm not sure about your experience level :p

If you're still unsure about adding extra media, I could make you a short video showing how I did it to my filters.

You can buy these types of things at a pet store (support your LFS - local fish store if you have one) but I generally get mine online. The polyester fill you speak of will also work perfectly fine, just be sure to rinse it well in dechlorinated water before use. Generally you just want to kind of mash it in to fill the space while not causing a flow problem - it isn't really an exact science.

Filter Floss Pad: http://www.amazon.com/Marineland-PA0100-Bonded-Filter-312-Square-Inch/dp/B0002565PW/

Bio-Media: http://www.amazon.com/Matrix-500-mL-17-oz/dp/B004PBD4J4/

I would stack things as follows:

[Filter intake flow]

[Filter floss (polyester fill or pad)]

[Bio-Media]

[Existing sponge]

[Filter output]

EDIT: I'll also second the recommendation of the aquaclear packs. They work well. Link here: www.amazon.com/Aqua-Clear-A1372-Aquaclear-50-Gallon/dp/B000A7BCG4/

oh no prob lol! I use aquaclear biomax but there are a lot of other products just like this you can use, like bioballs, ceramic things, even lava rocks! If it's porous (or has a lot of surface area) it'll make a good bio media. You can also use an all natural sponge for super good fine particle and bio filtration!

Well, if you want more than just a betta, go with the s15. I'll link you to everything I bought. S15 is two bucks cheaper with prime. I have prime, if you don't then just choose another seller. http://www.amazon.com/gp/aw/d/B0032G8TQQ?cache=06ba174150f5f99c861821c037a5d14d&pi=SX200_QL40&qid=1408422793&sr=8-1#ref=mp_s_a_1_1 Here's foam for mechanical: http://www.amazon.com/gp/aw/d/B0002AQK4S?cache=06ba174150f5f99c861821c037a5d14d&pi=SX200_QL40&qid=1408422856&sr=8-2#ref=mp_s_a_1_2 Here's bio media: http://www.amazon.com/gp/aw/d/B000A7BCG4?cache=06ba174150f5f99c861821c037a5d14d&pi=AC_SX110_SY165_QL70&qid=1408422856&sr=8-7#ref=mp_s_a_1_7 And then use a knife or a scissor and cut off all the foam of the three cartridges that come with it. Use that as filter floss, and layer it. I used the white balls that are inside the cartridges, as they promote bacteria growth. I added all of those from the cartridges, then the cloth from the cartridge, so it didn't float away, and then I added charcoal (skip this, if you want, I just wanted the tank to be clear while cycling, I'm gonna take it out soon) then the rest of the floss. All that is where the water comes into. Then I added bio max in the first compartment, then in the last two, the foam for the aqua clear. The motor is underwater, and I can't hear a thing! Like you have to strain your ears trying to listen, and its a barely audible him. My bio wheel, was clunky and was loud. Bearable loud, but loud non the less. And just put the last sponge of the three on the outtake, so current will be dispersed. Buy a heater too, and then the tank.

I use the sponge part + the bio ball things. I currently do not have carbon in my filter as I am adding CO2. If you have those bio ball media things from your old filter throw some of them in the new mesh. So yes you can run your filter without carbon in it, in fact I think most people don't run with carbon. here are the bio balls i am talking about.

You could also cut off some of the sponge from your old one or something (not sure about this never done it or read up about it)