Trust me bud we DESPERATELY need another knowledgeable salty at the shop. I think you would be shocked to see what we have in the shop and what we can get. Psh the first 2 ADA tanks that were taken home in AK were salt....@#$%!
plants, plants, plants and some fish. Some freaking cool plants and fish!
Oh, the Nuclear Green Palys that your store buddy looked at are relatively poor indicators of water quality. Zoanthids and palythoas are generally found in low flow tidal pools, with fluctuating temperature, salinity, pH and ORP (basically oxygen). They're pretty hard to kill actually. The SPS or stony corals on the other hand will let you know wheter or not there's a build up of nitrates or phosphates by whether or not they have extended polyps. If they're out and waving, then the water is generally all right. The LPS (fleshy corals with hard skeletons) do a pretty nice job of telling you what the calcium and alkalinity are doing. If they're all inflated and happy looking, then your calcium and alkalinity should be in check. If closed, something's wrong.
Of course, these are all just biolical guidelines. I reccomend that your friend egular test his pH, Calcium and Alkalinity at the least. From there, dosing the tank becomes extremely simple.
Also, I feel obligated to tell you that the palys that are in that tank, as well as some of the zoanthids (potentially), are known to contain palytoxin, the second most poisonous substance in the world. I strongly reccomend that you wash your hands after working with the tank, especially before touching your face. It would also be wise to wear gloves to protect your hands and arms from any exposure, although I don't. I should though! Here are a few nice articles for you. Happy reading!