The C series HOB's are good filters no doubt. But the Aqua Clears are NOT a waste of money. I just replaced my AC50 on my 29g with a C3. The flow rate of the C3 is a little less then the AC50 and the media is not quite as customizable as the AC50. This is due to the limitations of the usable thickness of the front most fiIter chamber. If its too thick the water can't flow all the way across the surface of the pad. IME my C3 is not polishing the water any better than the AC50 with the media I had in it. Sorry but IMO it is not the greatest thing since sliced bread. It's a good filter but not the end all perfect one. OS.
********************************
OS ..........this is because
the media you use in lieu of factory media is too thick. You are trying to use stuff not made for the C3. You are trying to use stuff you've already bought or that Rite-Size blue bonded media we discussed elsewhere. And if you're not using aquatic life non woven polishing pads or factory polyfoam or equivalent to capture micron particles, than the C series is of no value in polishing your water and I agree, you might was well use an aqauclear with floss.
In the C3, the design for the factory pad is for 1/2 inch which leaves plenty of space between the media and the back of the housing. Thus, using the 3/8 inch Acurel debris reducing pad like I do plus 100 micron Aquatic Life polishing pad which is 1/12th of an inch thick, it is the same or thinner than the factory pad thus leaving plenty of space for water to flow.
In the C4, it's 5/8 inch. Thus you can safely use 1/2 inch debris reducing pads (ie HBH) and 100 micron pads and be under 5/8 inch thick. Or you can do what I do and use 3/8" acurel + 300 micron aquatic life 1/12" pad + 100 micron aquatic life 1/12" inch pad and be under 5/8" thus leaving plenty of room behind the back for the water to flow.
Please ....... go to my photobucket link below:
HOB Filtration Photos by Paul1792 | Photobucket
and click to enlarge the pictures and show the explanations and go through the pics of both my C3 & C4 media and see how it works. The Fluval C can be serviced without even turning it off with zero mess. When I take out the aquaclear basket, everything falls apart and I end up with a big mess all over the kitchen counter. Stacking my media and straightening out the floss to fit it in the basket is a pain. I can change the mechanical media in my C series in about one minute.
When trying to use purigen, you don't have to touch the chemical basket for four months. Yet every time you take the AC50 basket apart it falls out and is hard to get it to fit back in right.
Same with the bio media. On the C series, you don't have to touch it for months at a time. On the AC, you have to remove it when you take out the basket and then get it to fit back in.