Fluval C2

authmal

Pseudonovice
Aug 4, 2011
2,621
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51
Phoenix, AZ
I just bought myself two new filters, a Fluval C2 and an AquaClear AC 20. It seems that everyone on here is familiar with the AC line of filters. As a "known" commodity, I intend to use it on my 10 gallon invert tank, which will have RCS, MTS, and eventually assassin snails. I may even get crazy, and try to get a group of OEBT at some point. Of course, a prefilter of some sort will be used to minimize the number of shrimplets I find in the filter.

However, the Fluval C2, while not a new filter, doesn't seem to be as widely known. I did a search on AC, and while "Fluval" returns a ton of hits, "C2" was too short to search for, and didn't seem to appear in the many false positives I skimmed. I intend to use this filter as a little bit of extra filtration/flow on my 55, supplementing an AC 70 and AquaTop CF 400 UV, and as my already seeded and ready to go filter for whenever I need to set up a quarantine tank. I'm at work right now, so all I've been able to do so far is look at the components and play with it a bit, but it seems to be more like a canister than a HOB, even more so than the AC line. I like the adjustable intake, so you don't have to look for extensions, you just slide it up or down as needed. It looks like I'll be able to use something, either a cut AC 20 sponge or possibly one of those Fluval prefilters, to prevent shrimp from getting into the filter, with ease. Inside, it looks like the media it comes with can easily be customized to be what you want it to be, as opposed to what it ships with. I'll provide some updates as time passes.
 
Well, setting it up was a breeze. It's kinda interesting in how it routes water.

Problem the first: the integrated strainer on the intake is slightly more bulbous than comfortably fits into an AC 20 filter sponge. I may acquire an AC 30 sponge and test it, or just deal with it, I haven't decided yet.

Problem the second: my intention to use it as an extra little filter on my 55 was thoroughly shot down by the fact that the rim on the 55 is larger than hook is on the filter. So, I'll run both filters on my shrimp tank. I'll probably just pull the biomax out of my AC 70 and throw it into the AC 20 (since I won't have a purigen bag or charcoal in it) when I need to quarantine fish.
 
I know it hasn't been a week, but the C series seems really well put together, in some respects, better than the AC series. I can see where some call it an upgraded AC series filter.

However, I don't think I'll ever be able to fully transition away from the AC series. It's too versatile. Double sponge? Okay. Double biomax? Okay. Charcoal (or Purigen) and cuprisorb? Okay. No sponge, double biomax, and charcoal? Okay. I'm running an AC 70 biomax and an AC 20 biomax in my AC70 right now, to seed the AC20 biomax more heavily before throwing the AC 20 in to a QT. It'd be more complicated to do the same kind of thing with the C2. Plus, there's no analog for the AC 110 yet.
 
I have both the C3 and the C2. The C3 has no problems with self priming, but the C2 needs a little help. Aside from that, the C2 is a very nice filter and does a great job on my 10G tank. I definitely like it much much better than the Penguin Bio Wheel.
 
My AC 70 is by far the loudest filter I have running, and it's pretty quiet. If I'm thinking about it or if I'm close to the tank, I hear it, barely. Then again, I think the plate over the impeller is slightly askew, and just haven't been motivated enough to check/fix it yet. If I'm in the living room, the couch is about 8 feet from tank, plus about 4 for the length of the tank to where the AC 70 is, I don't hear it. If my canister burps air, that's much louder, but I haven't had any air burping out of that since I did a tiny bit of DIY on the intake for it. Honestly, I have light bulbs and computer fans that make more noise than that AC 70 does.
 
i'm very fond of my C2. as mentioned earlier it seems to have a little difficulty starting the siphon, but once it's going it seems to do a great job. very quiet.

clean off the little white cloth "trash catcher" every time you thinks of it; this takes ~zero time, and keeps the crud away
 
After a couple of months of use, I have more thoughts on the C2. Yes, as stated by others, it needs a little help self priming sometimes. It's not a big deal, and I've long since been in the habit of scooping up a cup of tank water to start priming my HOBs.

However, I really don't think the C series is as versatile as the ACs. If I put a sponge as a prefilter, water flow is greatly reduced, where on the AC, there's little to no noticeable impact. If something small (such as shrimplets) get into the C series, there really isn't all that much space for them to move around, unlike the ACs. The sponge on the C just doesn't feel as robust and durable as the AC.

All those negatives aside, I definitely do like my C2, and have it running happily on my betta tank. I just have much fewer options with it.
 
I'm still loving my C2's (I have two now lol) and C3. I normally keep the flow rate to low because up to 50% of the water in the filter is re-processed multiple times (more impurities are filtered out).

I recently added a Zoo Med Nano 501 canister filter to my 6G Fluval Edge and I must say I really do like them a lot more than the HoB filters. I hope the C's I have last me a good long time, but when they do finally poop out I'll replace them with canisters.
 
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