The lifespan pf many of the more popular fish we commonly keep in the hobby can surprise many people.  Clownfish for example can commonly live up 15 years in captivity and many tangs can live up to 25 years.

http://www.int-res.com/articles/meps/134/m134p015.pdf

http://www.advancedaquarist.com/2009/12/fish2

Conscientious Marine Aquarist, 2008, Bob Fenner

Manufacture ratings should always be considered as guidelines and never hard fast rules.  In my opinion, almost all of these capacities are over rated.  The reason for my opinion is that manufactures typically complete their product testing with the gate valve and air valve(s) wide open to calculate the maximum flow rate and maximum air intake using these measurements to calculate the maximum rated capacity for the skimmer.  As we all know, the gate valve and air valve(s) will need to be adjusted in order for the skimmer to work properly which will also lower both the flow rate and air intake of the skimmer from the manufacture’s measurements.  This is why many hobbyist prefer to use skimmers that have a much higher rated maximum capacity than their aquarium.
The below link can help you determine how to pick out a skimmer for your set-up

https://www.reefaquarium.com/2013/selecting-a-new-skimmer/

And the below will offer you some other ways to evaluate potential skimmers

http://www.advancedaquarist.com/2010/1/aafeature

And some interesting skimmer information

http://reefbuilders.com/2012/12/20/protein-skimmers-function/

http://reefbuilders.com/?s=skimmers

If you are planning to use carbon dosing to reduce high levels of nitrates and/or phosphates, please keep in mind you need to start off slowly and at a very low level.  Making quick and drastic changes to your nitrate levels through all/any forms of carbon dosing will cause your water parameters to become at least somewhat unstable.  Take it very slow to begin with allowing your system to slowly adjust over time.   You have to always keep in mind, only bad things will happen fast in this hobby.

More information about carbon dosing can be found in the below article:

https://www.reefaquarium.com/2012/carbon-dosing-in-laymans-terms/

And a few other articles about carbon dosing

http://reefkeeping.com/issues/2008-08/nftt/

Don’t underestimate the importance of waterchanges!

In may low demanding and more basic set-ups, weekly water changes in the range of 5% to 20% would be all that you would need to replace the consumed elements from your water as well as helping to control excesses nutrient build-up. Many people do not realize that water changes when cycling your tank can also be very important and beneficial with harming or prolonging most commonly used cycling processes.

Waterchanges when cycling a marine aquarium with at least some live rock my actually help you out down the road. This is very different from a typical fishless cycle in a freshwater aquarium. Within the nitrogen cycle that develops in your marine aquarium, you will develop bacteria that eats the proteins and turns them into ammonia.  This type of bacteria will reproduce a lot faster than the ammonia eating bacteria, so the ammonia produced can actually grow to toxic enough levels that will prolong the cycle. Typically this point occurs somewhere around 1 to 2 ppm of ammonia. This is why you have to do water changes if the ammonia reaches levels of 1 to 2 ppm or higher. The water change will help reduce the ammonia and other decaying particles from the tank helping the cycle complete faster and the water parameters become balanced quicker. Although there is some beneficial bacteria free floating in the water, it will be in such small amounts that water changes will not remove enough of them to be impactful in any way. This is why water changes when cycling with at least some live rock will help the cycle move along faster, not slow it down one bit.  This will also help to limit the potential for higher levels of nitrates before the nitrate eating bacteria has a change to develop which will reduce the risk of nitrate build up within your rock.

And the below are some more interesting article that I found and thought I would share

http://reefbuilders.com/2013/09/04/reef-octopus-nwb-sss-super-space-saver-brings-performance-smaller-package/

http://reefbuilders.com/2013/08/30/mini-flipper-algae-cleaner-brings-magnetic-flipping-action-smaller-tanks/

When I took survival training while I was in the army, we were always instructed to get enough firewood to last you through the night and to complete this task before sunset.Once you had what you thought was enough firewood, get three times more fire wood that what you have. I have found this same simple principle should be applied to planning and learning about your marine aquariums.Once you think you have read and researched enough, you could stand to research some more (me included).

I have found the best way to accomplish this is by reading books and articles published by credible and experienced hobbyists combined with talking to fellow hobbyist and taking a good look at how they have set-up their aquariums.  Forums and blogs can be very helpful for you fill in the gaps or help you decide between the many options and approaches you are going to become exposed to.   This also is one of the aspects of the hobby that many people enjoy almost as much as they enjoy their aquariums itself.

The below are some articles that I found interesting and I thought I would share them.

http://reefbuilders.com/2013/09/24/bali-aquarich-shows-picasso-galaxylike-tomato-clownfish-pending-permissions/

http://reefbuilders.com/2013/09/09/gobiodon-species-red-sea/

http://reefbuilders.com/2013/09/09/life-spectrum-max-feeding-finicky-fish/