Even without the 'gag orders' (I dont mean to demonize RC, its just what I call them, and referring to them doesnt imply any brand in particular), I think that the reason they even exist nullifies my personal opinion's substance as far as 3rd parties are concerned, so I dont really even bother (something I have been open about). Having other owners testify with their own experiences could be assumed a more 'credible' and 'unbiased' means of forming an opinion than anything I could provide then, so I really dont have to say anything. That being said, I never suggested only one brand... and thats what does 'irk' me a bit. There are a few really good ones out there depending on what you want to spend and all. Thats about all I have to say about that.
When someone close to me asks 'Hey, would it be okay if I got this brand instead of this other one?', I rarely say no. Skimmers have existed and been functional for a very long time. I dont care if its 20 years old... if it works, it works.
3/4: I like the 8 bulb retro, but each IC660 can run 3 bulbs, so why not (unless your reflectors are too thick)? Its not a massive overdrive either... 3' and 4' bulbs get overdriven by a hefty amount, but 5' bulbs only get overdriven by something like 6%... as long as you keep the bulbs cool (something you should do anyways), I dont see this as a major 'bulb killer'. Keep in mind that an 80 watt ballast is really something over 90 watts at the plug... so being driven at 100 watts isnt as much of an overdrive.
You can go with 'stock' ballasts... 1x80's... I would say that your goal should be something like 800-900 watts of T5s for a 180. Sure, there are people who 'get away' with less, but they tend to grow their plate montis at the top, and they dont get the same growth as with more light... I think it might have to do something with some SPS that seem to fade as well. I have always run the same wattage T5 as with halide... if I replace a 250watt halide on a tank with T5s, I try to keep it at about 250 watts (or rather, I use the wattage at the outlet, so 275 watts (e-ballast) or 320 watts (HQI/M80). I have never had a problem with faded colors or reds/yellows/ pinks that looked chalky, and I run a very blue assortment of bulbs (lacking much of the warmer spectrums all together)... yet my orange cap still comes out neon blood red. And my growth never lagged.
5. Skip the Closed loop. Just use the tunzes. I shouldn't be so brand specific here though.... I know Hydor has some DC turbines as well with a slick looking controller. I dont know how much water they move or the price comparison, but they might be worth looking into as well.
6. If you want an AC Jr. that is a 'step above' the basics that I have mentioned... and is a good idea to control heaters, pH probes-CO2, etc.
13. Substrate: I have tried and now avoid: Oolitic/Sugar Arag. Too fine to 'breathe', sure it can have anaerobic pockets in very shallow areas, but that also means a single critter can disrupt it that much easier. The stuff gets dirty and has the same density as the crap it collects, so its hard to clean (detritus trap). Sure, the critters love it, but as it turns out, oolitic is also a poor buffer due to its chemical nature. This stuff tends to clump up, turn colors, blows around and makes clouds way too easily.
Silica: stay away for many of the same reasons given with oolitic. The fine yet sharp edges (pretty much crushed glass) isnt nice on the delicate membranes of critters that ingest/sift it. I know some will challenge me on this because 'they used it and it seemed fine' or 'someone else said so', but IME, fish have died from passing it through their gills or burying themselves in it.
'Seaflor Grade'... the stuff thats 1.0mm and larger... like 1.0-2.0mm. If you run your hands through it, you can feel it... it has some sharp edges. IMO, when I had it, it was large enough to trap detritus in it almost too easily. It wasn't 'burrower friendly' either... my nassarius snails didnt seem to like it much at all. If you look on CaribSea's own site, they even say its not 'burrower friendly':
http://www.caribsea.com/pages/products/dry_aragonite.html
The best stuff I ever used was the Nature's Ocean stuff... its either the Aragonite Natural White #1 or the Samoa Pink. It is right in this 'sweet spot' of .5-1.5mm, and is very soft to the touch, yet isnt so light that it just blows everywhere. I have some bags still downstairs... I should see which one it is. Great stuff though. Im sure getting it dry though is just fine. But the main idea is to get something soft in the .5-1.5mm range. The critters seem to like it the most, and its the easiest to clean (it keeps itself clean more to a certain extent).
And of course... there is 'bare bottom' as well. I tend to go for a sand bed that is 1-3" everywhere... about 2" on the average. Enough so that getting blown around a little doesnt uncover the glass right away, but nothing more than a cuke or snail needs to hide. Rather than cultivate a DSB or sand bed in a 'static' manner, I remove a small percentage every few months... I target the cruddiest looking 10% say... and I give it a good wash in a bucket with freshwater until the water is clear... then I put it back in the tank. Sure, I just killed the sand, but I also removed alot of organic waste and the remaining 90% will quickly respond and re-seed the fresh-cleaned raw sand. This way, my sand doesnt 'build up' gunk that contributes to the 'old tank syndrome' with elevated organic levels, but I also dont have detritus that I have to clean up every other day that just keeps blowing around the bottom because there is no sand. IMO, the sand helps prevent that stuff from just rotting out in the open... the sand is a biological filter in that respect, helping trap the raw crap and start processing it while its in the sand. Its just that from time to time, you have to take some of the compost out before the heap gets to be too much for the sand, and you end up with something like a DSB that 'backfires'.
Crushed Coral/Crushed shells, etc: best to avoid as a substrate... stick to arag.
