<a href=showthread.php?s=&postid=10516981#post10516981 target=_blank>Originally posted</a> by JeffReef
Yeah, Justin. From the picture it looks as though the Zoas were only a couple of inches from the top. But in reality, they were about 5 inches from the water column as the rack was only 10 inches tall. The rack was roughly 10 inches from the light fixture.
I can't comment on your 175w mogul MH as I have never used them. But from what I've read in the past, the HQI bulbs puts out more PAR than mogul based bulbs. So, Edwin's 150w HQI's may put out more PAR than your 175w MH - I don't know.
Edwin never mentioned that his Zoas were browning out. If he said or meant that his Zoas were, in fact, browning out, then I would suggest that he move the Zoas closer to the light. But it would be very hard for me to suggest adding more lighting to a 12g tank that already has a 150w HQI MH on.