My LPS 20gal. reef has been running under this fixture now for 1 year 1 month. All corals never lost any of there coloring nor bleached from the cross over. Matter a fact my Xenia's have...
Sadly ours died last week (pump malfunctioned and caught fire which had a domino effect of other water issues). He would hop along the front of our 200 gallon tank, loved to race back n forth....
Picked up my CB Target Mandarin from our FedEx station this morning. To say I'm disappointed about the condition of this fish is putting it mildly. I've yet to see a fish so skinny and still...
I have a mag18 on my 125g and a mag9 on my 65g. I am very happy with both. They are very quiet and efficient.
The 12 should be good on your 90g. Keep in mind that the amount of flow you get will depend on head space, turns, etc.