How long do you run your MH?

[Greyghost]

How long do you folks run your MH? In a nutrient poor system, Is it necessary to run MH for more than 4 to 6 hours a day?

[fkadir]

Im running mine for 6-7 hours daily. 3 x 250w DE.

I generally find that running MH photoperiods in excess of 8 hours results in lightening of SPS colors, 6-7 hours works for me.

[gqjeff]

7 hrs

[G.Alexander]

3 x 250 W BLV 14k bulbs 7 hours
4 x 80 W T5 blue 12 hours

G.Alexander

[Orion76]

20K - 7 hours
10K - 5 hours
6.4K - 1 hour

[gqjeff]

forgot to add I run my t5 and vho actinic 12 hrs also...

[Greyghost]

Thanks for the reply guys. Seems like I run my MH too short. 4 1/2 hours. But it seems that when I run it longer than that, my corals starts lightening up.

[Diesel3443]

I run mine 5hrs. Actinic runs 12hrs

[Miguelito]

I run my 2x250W Megachromes 14.5K for 4 hours, and my 2x80W T5 Actinic+ for about 12. I did it on accident, then decided to stick with it. I have excellent growth and very good colors, with lots of blue SPS. Even a cool wild stag I got from fragfarmer is back to its awesome blue base to tip, and growing has grown 2" since I got it a couple months ago.

Thats not very much light on a 150 so I was pretty surprised.

[Louey]

I run 4 X 400's for 10 - 10.5 hours per day. I have no supplemental lights, so it's MH all day long.

I was thinking about making it a longer photperiod. lol

Louey

[gqjeff]

Ghost, color temp of the bulb and the wattage of the MH make a huge difference also.. DO not forget that when thinking about photoperiod length.

Jeff

[Greyghost]

Ghost, color temp of the bulb and the wattage of the MH make a huge difference also.. DO not forget that when thinking about photoperiod length.

Jeff

That makes sense. So if I decide to go from 14k Ushios to something in the 20k range, I need to lengthen my photoperiod to compensate for lower par?

[fkadir]

Yup, logically you would need a longer photoperiod for higher temp bulbs with the same wattages to achieve the same effect.

[nyfireman3097]

i HAVE 400Wers 4 hours a day and 2 hours before and after for the actinics

[Orion76]

Yup, logically you would need a longer photoperiod for higher temp bulbs with the same wattages to achieve the same effect.

Agreed. More important than the exact length of your photo period is meeting but not exceeding the daily energy requirements of your corals. The more intense the bulb the less hours it takes to reach this point and vice versa.

As a gross generalization a 10K bulb typically is nearly twice as intense as a 14K or 20K bulb.