is this enough of a photoperiod.

[Vanquishxxxx]

have always kept my little at 8 hours MH and 10 hours T5. I have 2 54/watt t5 which stay on for the 10 hours and 2 250/14k mh that stay on for 8. i want to lower the MH to 630 hours and and t5 to 8 hours. You think this will be enough. Its a normal 75g tank and the lights are about 9 inches off the water

 

[Alex T.]

If it's any consolation I have 2 400 watt Radiums on Galaxy ballasts on a 6 foot long and 27 inch deep tank for only 6 hours per day. My rockwork is only half way up and the SPS are colorful and thriving. The only supplemental lighting is 2 5 foot actinic VHO's. Because of how low my rockwork is there is great spread of light at deeper depths without anything being shadowed.

I've always tried to give my SPS just enough light and no more than they need to color and grow. As long as you could provide enough intensity and keep your water crystal clear I don't see any harm in a 6.5 hour halide photoperiod. In the summer I only have them on for 5 hours and nothing changes. It's also a nice bonus on the utility bill to not run them longer. Lighting is only part of the equation. I think a good 14k or even 10 k bulb with a shorter photoperiod may even do you more good than harm. A friend of mine has a shallow frag tank with a 250 watt Radium with a large Lumenarc Reflector on a light rail that is only on for 5 hours per day. His growth and coloration are insane. He's also able to keep the Lumenarc only 6 inches from the water. With this short of duration and the amount of intensity that they receive as the light rail passes it's more than enough where every three months he has 50 or sixty frags for sale.

 

[Underwaterparadise]

I only run my Halides 4 hours per day. Honestly with that much light on a 75g 8 hours is overkill IMO.

 

[Vanquishxxxx]

yeah lowered them to 6 hours and 830 on the t5. See how that goes.