My thoughts,
1- skimmers - H, Extremely important. Garbage out. 'nuff Said. I do think people should be more conscious of nutrient inputs however in the form of food, source water etc. There are frankly though a lot of skimmers out there that are mediocre and many people waste money on junk, trying to do it on the cheap, then end up spending a lot of money once they get serious about the hobby anyways.
2- halide lighting - M - H, There are still issues with cost and waste heat but MH lighting really opened up the keeping of more demanding stony corals, anemones and clams that were marginal under previous lighting schemes
2b- fluorescent lighting - M, Was all we had when we started with marine tanks in the 80s and it served fairly well once we understood that photosynthetic corals need more light. VHOs I will always have a soft spot for but their replacement cost, relatively short usable lifespan and akwardness made them a iffy transitional lighting technology. If you include T5s and Power compacts in this then might make it slightly higher as these were more intense and capable of a larger array of captive organisms to be kept at a reasonable price.
3- shipping methodologies/quality on arrival - M, Can't sell something and hopefully learn its captive care needs without getting it to the LFS or Aquarium alive in the first place. I definitely see better specimens and a wider variety of animals but this is a double edged sword. You can keep a larger percentage alive, passing the lower cost to the hobbyist / purchaser but this makes people hunt for ever cheaper livestock. Fish and corals should not be a commodity and while captive lifespans of fish and inverts have gone way up, I am making a judgement call here, the lower overall price of these organisms has made many novice reefkeeprs somewhat less driven to learn and care for their charges to the best of their ability. This should be an elitist hobby in my humble opinion if for no other reason than to have people be more realistic about the sourcing of their animals and a dedication to keep the organism for as close to possible to its natural lifespan.
4- coral farming - M, I've seen a lot of great stuff come in from domestic farms. Some of the maricultured colonies grown some south pacific nations still seems to be iffy on short and longterm survivability. Overall a net gain but I know of a few 'respectable' coral farmers who still chop up wild colonies and sell them as aquacultured. Trashy, but the profits to be made in exclusive / rare / flavor of the month coral frags in the first half of this decade were pretty impressive.
5- fragmentation - H - Corals for the masses. Theoretically takes pressure off wild stocks in the long run but I don't know of any way to quantify this. Definitely has helped make the hobby slightly less cost prohibitive but related to my point in number 3, there are a lot of people keeping (trying to?) tanks who have no business doing so. Again, a judgement call on my part.
6- live rock availability - H (though this might very well fit in with the Berlin method). The key to any system ( going back to the Eng method even?) but I'd like to see more of it maricultured domestically in the tropical Atlantic or possibly topical East pacific for variety.
7- nutrition/food - M - This has helped with some invertebrates but really moreso with fish. The array of quality dry, frozen and live food available now as compared to 20 years ago when I started is staggering. The flip side is there is so much snake oil and dubious claims made with little oversight. Particularily in the 'supplement' market. Very little regulation and I won't name names, but some of the products I've tested are flat out junk if not unintentionally harmful to some tanks.
8- quality media/disbursement of quality information - M , there are so many different ways to 'succeed' and frankly there is a lot of bad information out there at the retail, printed, and hobbyist level. What printed resources available that are solid (ex TMCRA series or the Sprung / Delbeek series) suffers often from high price / limited local availability.
8b- internet as information source - H , much more egalitarian method of disseminating reefkeeping information. Has the same potential pitfalls of misinformation, myths and egotism but collectively people are learning what works best and at the core it makes the hobby much stronger.
9- increased activity - local, regional, national clubs - M, Not sure on this one. Most of the clubs I've been involved with start out with noble intentions and devolve into swap meets and places to leverage membership into group buys which cuts into LFS business. A lot of churn in this hobby and few of the people that I started out in this hobby with here locally are still really into it 10 years on. Definitely a hobby for a bullish economy, a lot of people try it , get frustrated / see how much work is involved and unload their tank off on the next starry eyed wannabe reefking.
10- Berlin method - H , Other than the evolution of things like DSBs , refugiums and ancillary reactors , we still use the BM as the foundation for the bulk of modern reeftanks.
11- other? - Was going to suggest chemical / mineral supplementation (Kalkwasser I am assuming you include with Berlin method) , accurate test kits and measuring devices (
refractometers, ph meters etc).
