Well
FWIW, I sense you are trying to set up the
SW tank modeling after the
FW. There are a few different schools of thought here in terms of what exactly you need and the few things I will mention here are meant as a guide and an example of what most
SW hobbyists do to successfully set up and maintain their tank.
WATER: It is recommended that you use
RO/
DI water for your tank, normal tap water, even when dechlorinated, still contains undesirables like phosphates and other dissolved metals. However, there are some who successfully maintain a tank using dechlorinated (chlorine and chloramnine) tap water
SUBSTRATE: Recommended substrate is a sand bed. Quantity should be about 2Lbs. per Gallon of tank capacity. The Crushed coral and gravel makes for potential bacterial issues and marine fish naturally live in a sand bed environment for the most part.
AIR PUMP: Lose the air pump. Not used in a marine tank. What is recommended is one or more powerheads to keep the tank water properly aerated. That combined with the regular circulation pump and skimmer will keep an acceptable oxygen level in the the water. Based on you size tank, at least 2 Maxijet 1200s will do nicely in the tank.
STOCKING: I get the sense here that you set up your tank, then dropped the fish in and turned everything on. Couple of things here. You mentioned that one of the damsels is laying on its side. that is a sign of severe stress. First off, your tank needs to be cycled properly before you add any livestock to it. Forget the turbo. If possible, I would return the fish to the store, and start the cycle of this tank. This will take about 4 weeks to complete. What is happening in that period is that you are allowing successive colonies of nitrifying and denitrifying bacteria to grow and flourish to handle the successive spikes of ammonia and nitrites in the tank (both of which are toxic to the fish). Your damsels are probably suffering through an ammonia spike right now. There are many references here on how to cycle a tank but the most humane and preferred method is to use cocktail shrimp to kick start the process. Also on that note, I seriously urge you to take the time to acquire a couple of books on setting up a marine tank (see reference section here for recommendations) and successfully stocking and maintaining it. I understand that you want eye candy, but if you really do not want to take the time to properly set up and maintain a
SW tank (which takes a lot more time, effort and expense that
FW), then I suggest you use plastic fish
AQUASCAPING: The fake coral is fine is all you want is a
FO tank. This is a purely subjective choice of how the tank looks.
LIGHTING: For a
FO tank, lighting needs are minimal. a standard fluorescent hood with 4 tubes should be fine for your tank. Keep in mind if you ever want to consider adding inverts or corals, you will have to do some serious upgrades to lighting and add
LR to the tank.
FISH CHOICES: Damsels are a good beginner choice. Again, I would recommend that you research the fish types available and this will include which ones are hardy and also you get a chance to see what type of fishes appeal to you. Remember this is your tank. Stock appropriately being aware of issue of compatibility, need for hiding spaces and feeding requirements.
TESTING: You will need a good marine test kit. Tests for ammonia, nitrite and nitrates during the cycling period. Then nitrates, pH and specific gravity. Also a good thermometer for the tank and a heater to keep warm if that is a problem. Again, all of this would be covered in your research.
This is quick and dirty and I hope it helps put your efforts in perspective. A
SW tank is dramatically different that a
FW tank. I have had both. Please take everything I have said here in the light of trying to help you get your tank started the right way, so that both you and your fishes will be happy.
HTH 8)