PF

I have set up a brackish 55gal tank & put in 1 full tablesppon per 5 gal as recommended on API Aquarium salt box, so 11 tablespoons. Is this enough? I also put my large pleco in there which is about 8 inches long and he seems to be doing fine. I'd like to keep him in there but from some of the things I am reading people are saying 1 teaspoon of salt per gallon. Didn't know if I should use more salt or minimum necessary to keep pleco in tank with refernce to fish listed below.

I have 1 Mono Sebae-small and plan to get 2 spotted puffers, a Ruby Scat, Green Scat, and maybe a couple of Goby's.
Also, wanted to know if O.K. to feed these fish Dried Shrimp & plankton. I know the puffers like this but wanted to make sure if ok for others to eat or focus on giving them the flakes? Ideas and advise on the information I gave and fish combinations would be appreciated, thanks.

as the person above says, you need a different type of salt to make a tank brackish, the same salt used to make marine tanks salty and you'd need a hydrometer to check on the salinity.

also, plecos are salt intolerant, remove him asap or he will die from kidney failure.

looks like most of the technical problems are solved, now for the logistic...

that tank would be way overstocked, monos are schooler as are scats, scats get over a foot long, puffers are very territorial, the puffers you want need to evetually go full marine, gobies may or may not be truly brackish, plankton will go unoticed and foul the water...

personally i would just do the school of monos, one goby, and/or maybe an archerfish

API aquarium salt is not salt. It is a fish tonic, to prevent disease. You need instant ocean. For full instructions, please look at this site, it is an excellent start up guide:
http://badmanstropicalfish.com/brackish/brackish.html