Back in the day (circa 1986) that's the way we all did it. That was "the way" it was done. If the live rock was cured and the person is proactive in regards to water changes and less than desirable test results, all will probably be fine.
Sounds like you need some added flow though. Look into a Koralia 2 or comparable water mover. Do plenty of testing in the next few weeks and add nothing else to the tank except cured live rock until the tank stabilizes.
There's Many different ways to do things, some are better than others for sure, but good husbandry can still intervine in this situation and make it all turn out fine.
Good luck, and happy reefing!