View Full Version : light duration for this T5/MH?

12/23/2009, 12:23 PM
How long would you run these lights growing acroporas?

2 ATI blue plus T5
2 175W iwasaki 15K SE on magnetic ballast and hammertone reflectors.

tank is 48" x 20" deep but actual water is not 20" deep.

12/24/2009, 10:20 AM
T5's - 10-12 hrs per day
Halides - 6 hrs per day

12/24/2009, 01:26 PM
8 hrs a day for both lights.

12/24/2009, 01:33 PM
T5 - 11am - 10 pm

MH 12pm - 7 or 8 pm

Shown for duration, actual times can vary.

12/29/2009, 12:32 AM
The MH is very white and stimulate growth less color then if I get a 20k bulb.
So for the T5 if I run them longer, like 12 hours a day, would it show color more similar to having a 20k MH bulb because the coral has more blue light?

12/29/2009, 01:09 AM
T5's - 8-10 hrs per day
Halides -5- 6 hrs per day
This way you don't have to change the light for a year maybe. Have lights hanging from 6-9 to nine inches from the water.

12/29/2009, 01:10 AM
I was told to replace T5s and Halides every 6 months. but this doesn't really say how many hours the bulbs are run...

12/29/2009, 01:44 AM
That Iwasaki bulb will last for 2 years running 6 hours a day. Mines been running for a year with less than 5% drop in output. You could change out the t5's every 6 months or so as they will lose intensity pretty quickly, especially next to the halides due to heat.

12/29/2009, 06:09 AM
What little research has been done on optimal photoperiods seems to hint that anything over 11 or 12 hours may in fact hurt corals rather than help. I run my MH 10 hrs, and very weak actinics for 4 hours.


A Different Look at Lighting: Effects of Prolonged Photoperiod, Spectral Quality, and Light Dosage (http://www.advancedaquarist.com/2009/5/aafeature)