Goniopora corals are near impossible to keep, there living conditons in the wild are very extreme. The water they live in is so murky or dirty that divers have trouble seeing in front of them. The water currents they live in are very strong and turbulent.
95% of these corals die within months to a years time in captivity.
Having Ideal water conditions is only a very small percentage of keeping them. They usually end up dying from the corals tissue receding from disease. Once that happens there is nothing you can do to save it.
They need expert care, and even then they usually dont seem to fair to well.
They do need to be fed Phytoplankton 2 to 3 times a week, be in a high flow area and high lighting.
I believe the LFS told you it would be a good first coral just to make a buck.
Anyway good luck with it, I hope it does well.