Sorry for the lack of updates, the internets been down... and I haven't taken any new pics.
Yeah, xVitox, I reviewed that system when designing mine. It has a lot of strengths in it's simplicity... if I wasn't concerned with keeping the hardware out of view, I would have built something similar. But for me, having powerheads in the tank isn't so desirable... so I used the canisters to do the job for me. Something to consider in making yours, that I had been thinking about a lot, is using a matten-filter style filter wall at one end of the tank, but using power heads to drive it... essentially the system as designed in the thread you posted, but instead of foam tubes on one end and powerheads on the other, you could put the powerheads behind a wall of foam, and plumb he output to the other end of the tank.... it would simplify things a little, and be easier to hide, in my opinion. check out the german "matten" filters...
the tank's looking good, I've been doing small water changes to try to eliminate the surface scum build up, seems like all the air bubbles and residues from the build are giving me the typical new tank film on the water. I'm hoping when I kick on the second filter in a couple of weeks, this surface scum won't be an issue any more... but it's a tough call, the majority of my tanks have the water return right at the surface to break the surface tension. This does not.
There's a lot of air bubbles coming in through the eheim return... I'm guessing that the highly aerated water behind the wall is being sucked into the filter, and then bubbles collect and shoot out in bursts. I've experienced these kinds of bursts from new set ups before, but nothing as potent, long lived, or frequent as this. It's like a big burst of bubbles every few minutes. I like it. I hope it's a sign that aerating the water behind the wall is going to be enough to support the hillstream o2 lovers. I'd be fine with this being the long term method of o2 introduction.
I've also been seeding the tank daily with small algae cultures and daphnia from my bare bottom riparium. The bare bottom makes it much easier to find groups of daphnia and suck them out. I have algaes growing in petri dishes, and add small amounts every day, when I remember. I'd like to add a larger, lab style daphnia colony to the tank, but have been on the fence, worrying about over doing it.... and not wanting to spend the 20 bucks. I'm not seeing any algal growth on the rocks yet. But the rocks do feel fuzzy in most spots, the first signs of biofilms. I try to rub the surfaces of the stone daily to spread the algae around and keep sand dust from settling on the surfaces. I left the light on all night last night, but it's been on a 12 hour timer.
I also removed a fair amount of the mixed sand, and topped it off in most spots with flourite black sand. I'm not sure how I feel about it, I almost thing it looks too flat and dull now. The GF preferred the mixed sand... so I may switch back, and also add small bits of eco complete here and there to create a little variety. The bag of eco I got seems to have a lot of big chunks, so I may crack open some flourite black, which is smaller and might mix well. dunno. more work!
It's also been a daily task to fill in the holes sucked in by the undergravel filter. The water level behind the wall is 1" lower than on the tank side, from the suction of the filter pulling a bit harder than the gravel lets water in. it's sucked open a few cave areas, which I've been using a skewer to pack in and settle. I think all of the suction caves are now filled in. This is important because I expect the gobies to dig caves in these areas, and don't want them to create land slides that trap them. I'm confident that the gravel is to the point where it is stable and most of the forced erosion and packing has occurred.
I've been waiting to add the first group of fish, a school of Microdevario kubotai (listed as Burma Yellow Neon Rasbora) that will inhabit the upper regions of the tank. They clearly like the high flow, spending all of their time right in front of the filter returns in my 20g cork tank. The lighting in the cork tank is not so hot, so I don't get to really see their bright neon colors in there, I'm hoping the tank switch shows them off. I had been worried about their health though, just paranoid, but I lost a few, a couple of months back, so I've been treating with fenbendazole flake for the last few days. I just don't want to introduce anything to the gobies. Tomorrow is the last day of treatment, then I will acclimate them to the 30g. If all goes well with them, then we're good to go!
Photos soon. Keep yer eyes peeled.