I've read through the entire thread and have to thank Gunner profusely for taking what was a curiosity on Ebay and making it a serious contender for my next purchase, with his mods (and likely the plywood pressure distribution flange pictured above or something similar).
That said, I could get a Eheim Pro II 2026 rated for up to 90G -- reasonably sure that's the model in question, I will double-check -- used from the local fish place for $120 out the door with a new gasket and good media included, or I could order the CFS 500 from topdogsellers on Ebay, wait a week+ for it to get here (I am a sometimes impatient soul) and spend a few hours and a few more dollars doing the mods, so call it $65, $70 + mild frustration. Roughly half the cost, and I'm on a very tight budget as a law student right now.
The question is, either of these would be going on a fairly small 29 gallon tank with a single Green Spotted Puffer (~2.5") and a small Pleco (~3.5-4"). I'd also be keeping a Penguin BioWheel 350 as a backup hang-on-the-back. Yes I know, I am crazy, way over-filtering, but GSPs are extremely messy fish and sensitive to water quality, and I love my fish. I'd have them in a 65 gallon if I had the space, but my living situation is far from ideal right now.
Which is better for the setup, ignoring price entirely? I don't need total silence, but either one will be about 5 feet from where I'm sleeping and probably not inside a cabinet (just tucked in the corner) so I would obviously prefer something that's going to be really loud or grating. Reviews I've read suggest the Fluval filters (which the CFS line seem to be based on) like the FX5 are considerably louder than comparably rated Eheims. I've had Eheim pumps before (custom computer watercooling) and was impressed with their quiet operation, though flow rates were not that great and price was very high, even used, as here. It's also worth noting I don't know how old the Pro II is or anything about its history, so I have no idea how many hours are left on the pump or if it was ever run dry, anything like that. I really like my local fish place (Fishy Business! If you're in Columbia, SC or the surrounding areas I bet you know it) and the guy that owns it is extremely friendly, knowledgeable, and has been willing to point me to used tanks and such in the past when I expressed concerns about my budget. Their prices aren't too bad for a local shop, but a little on the high side. I suspect I could get a used Pro II somewhere else a lot cheaper, but the guy said he'd go through and make sure everything was in working order before selling it to me, and I trust him to do a good job with that, so that's worth something to me assuming it isn't determined $120 would be a rip-off for a used 2026 in good condition.
I do enjoy modding stuff, I come from a background building custom computers and doing extensive case modifications and full custom water cooling systems, so I know my way around basic tools / saws / drills pretty well. My primary concerns with the CFS 500 are noise levels, longevity, and inability to easily and quickly obtain replacement parts should the need arise. I'm poor, but I'd rather buy something I can trust to keep working. I treat my things well and take my time where it's needed, so if that's enough to ensure years of operation out of the CFS 500, I'm fine with it. If there's a good chance it'll give up the ghost for no good reason at some point, I'd like to steer clear.
In other words: If I get the thing, take my time and do the mods, and treat it right, is it going to be really loud or break one day, dumping half my tank all over my (rented) floor, losing me a $700 security deposit because I tried to save $80? Am I better off with the Eheim? Are there other places I should be looking? Are there other models or manufacturers I should be considering? I realize it sounds like I'm asking you to do my research for me, but I've been reading for hours, have little real world experience with this stuff, and my head is spinning. My last tank was a 20 gallon tropical setup with an angel fish and a few others when I was 11, 15 years ago. I just got back in to the hobby about a year ago because I wanted a puffer, and I'm still feeling a little lost despite tons of research. There doesn't seem to be a lot of consensus among the fishkeeping community -- the last 15 pages of this thread behind no exception at times.
I imagine people here or on other aquaria forums buy and sell used stuff regularly, should I be looking those kind of places? I'd prefer not to buy something like this used sight unseen. Too many potential issues. Already put an ad up on Craigslist locally, but people around here are crazy -- they think their used 75G with a broken brace and horribly done home re-sealing job is worth $150+, that kind of thing. I'd be amazed if I get one reply from my "want to buy" ad, nevermind anything in a sane price range.
Suggestions?
EDIT: Also! Where should I get "poly blanket"? The fish store? Somewhere else cheaper? I'm all about saving money so long as there's no big sacrifice to quality and it doesn't hurt my fish. Is there any 'trick' to using construction sand as substrate, apart from letting it settle out and filtering well before adding anything?
2ND EDIT: Saw Gunner's other thread about using washers and neoprene / another squishy material to distribute the pressure, might just go with that if I decide to go with the 500. Also, apparently SunSun is calling themselves Perfect these days. Should I be considering those? They're cheaper but I dunno, would they be more than sufficient for my setup? What kind of difference in maintenance interval / cost are we talking?
Aaand.... sorry about the wall of text. Wow.