maristar owners what ballast setting?

Ideally this depends on the bulb being used in the fixture.
The system is designed to drive a 250w bulb, and can be dimmed to get lower light from the 250w bulbs, driving them at 175 and 150.

However, some 150w bulbs and 175w bulbs can be used on the respective settings, and work fine. But since the system is not originally designed to drive these 150 and 175 bulbs, some will not fire on due to the specific requirements on how the bulb's internal gasses are ignited initially. I've tested it on Ushio 150w bulbs and it lit up fine at 150w setting, but the Iwasaki 150w could not start on the 150w setting and will start on 175w setting, but that's over-driving the bulb by 25w so life expectancy of the bulb will certainly suffer I would assume.

So the best way to use the Lumatek LK250 is to use a 250w rated bulb, and choose what output you want them bu dimming them at 150 and 175 settings.