Just wanted to share my experience with this filter. I recently purchased one from a friend who had bought it 3 months ago as a temporary filter. He works for the LFS
so he got it half price, and sold it to me for half of that, so I only ended up paying $10. It is the C3 and I must say it really is a great filter. Very easy to maintain, very quiet, actually silent, even with the trickle chamber. Only gripe is they could have made the filter box a little more durable....looks like you dont want to drop it or it will break. I used it to replace the Aqua-king on my 37 gal
hex tank, and it seems to be doing just as good of a job, even though it is half the flow rate. If you are in the market for a simple filter that does a great job, I would definitely reccomend it. 5 stage filtration from a HOB
, even at retail cost, to me would be well worth it!