Thanks guys. I know generally going bigger is going to make everything more stable and in a sense easier. Most of my equipment is way overkill for the 90g. Two Tunze 6105, skimmer is rated for 300g. etc. Really what I'm looking for is whether or not there is some unforeseen aspect or cost of owning a large saltwater tank. In perusing the board I've seen people downgrade because the upkeep and expense was more than they thought it was going to be. Granted most of those setups were sps and around 300g so I know it's all relative.
I was also curious how well that tanks footprint would work in a saltwater setup.
Well as far as the footprint goes, its a long shallow tank, so light penetration will be easier. I personally prefer more depth in aquarium for aquascaping. I think you will do fine. Well just starting off, you will need more than you listed to get started. As some people stated you will do yourself a favor by purchasing an RODI unit and an 40gallon trashcan on wheels for water changes. Or whatever you decide you want to use. Some additional initial costs will be the following that I can think of:
Initial:
1. New Sump
2. Plumbing for new aquarium
3. More Sand if you use it
4. More live Rock
5. Return pump. Something to run all of your equipment.
I believe the basic husbandary costs get some people over whelmed after their initial investment. They start to add up after a while. One little bottle of calcium additive that used to last 6 months is no longer applicable for example. Your cost for the following goes up. Just a few but not limited too....
Additives:
1. Calcium supplement
2. Magnesium supplement
3. PH/ALK balancing
4. Potassium
5. Strontium
To make your life easier for the larger aquarium, I recommend the purchase of the following things. Now you don't have to buy any of these if you don't want too, and you can keep a reef without buying any of them. I"m just giving you some things that will automate allot of your chores and make keeping the reef allot easier.
Recommended:
1. Controller
2. Carbon Reactor
3. GFO Reactor <= If you are going SPS route which sounds like you are not. This may be over kill.
4. Good UV sterilizer
5. Auto Top off <= A most IMO on big aquarium as water can be evaporated at a rapid rate.
That's a good start. So I hope this helps. My recommendation list will help you not to do a bunch of water changes. I do not perform many water changes on my 255 maybe 40 gallons a couple times a year that is about it.
Happy Reefing.