Yes looking to get a school of cardinal fish, some pipe fish, and some other stuff that will make good seahorse companions.
Ok well let me warn you before hand. Sea Horses are VERY VERY VERY VERY hard to keep, your tank needs to be very well established, IE 6 months to a year old, With a High Copod and other "little Critters" population. Sea Horses Will only eat live Food. Same with Pipefish(which are a type of sea horse sorta) Cardinals are fairly hardy as far as SW goes(not many "Hardy" SW fish.) You will need a PH of 8.4 or so and it has to be STABLE! Sand and Live Rock will be VERY VERY important with what you want to keep.
The rule of thumb is 1 lb of Aragonite Sand per Gallon of water, and 1 to 2 Lbs Live Rock Per Gallon of water. So your looking at about 225 lbs of Aragonite Sand (Don't Skimp here and use play sand PLEASE for the love of god buy Carbisea Aragonite sand!)And 250 Lbs of Live Rock.(Buy cured live rock if you can trust me the smell of curing live rock is HORRID!!!!!!)
With what you want to keep it will be very important that you do get a cup or two of sand from as many established reefs as you can(Do this AFTER your cycle is done) If you can get 1 cup from 30 or 40 different established Reef tanks DO IT!!!!!!! Each tank will have different micro fauna,copods,bristle worms etc.
Also i highly suggest using a high quality salt mix, Reef Crystals is a VERY good brand.
To Cycle a SW tank it is Similar to Freshwater, Use a Piece of fresh sea going fish, or a few cocktail shrimp with the tails removed. toss it in and forget it is there, let it rot away. For a 225g tank i would use 8 jumbo cocktail shrimp or about 1/2 to 1 lb fresh ocean fish.Type of fish doesn't matter as long as it is an ocean going fish. Cod,tuna(NOT CANNED) Halibut whatever is cheapest locally. Leave it Raw but do cut it into Small Chunks about 1 inch square seems to work well. And dont fish it out in 3 days like some will tell you to, in SW you want a strong cycle. Stronger cycle = Stronger Bio filter. Also Add the piece of used filter media to the tank the same time you add the shrimp or fish pieces, and leave it float Wringing it out ever day and then dropping it back into the tank. Leave it in the tank till the cycle is done.
If you have any Specific questions feel free to PM me or Email me at [email protected]