Raduims 20k - how many hrs you leave on

[jarrett shark]

I am trying to find the right light cycle for my sps. I have 3-400w over my 220gal and i am currenty leaving them on for 5.5hrs. I know 20k has less par and i wanted to hear from others how many hrs do you get great growth..

 

[my40breeder]

8-9 hours for me. typically 20k bulbs do have less par, but radiums have pretty high par values

 

[jarrett shark]

Wow 8-9hrs, maybe thats why some coral stopped growing. I always did 7hrs but reading i was told less is better

 

[allsps40]

I run mine for 5.5 hours.

 

[reefereef]

i used to run mine for 8 hours

 

[Reef Bass]

8 hours. I don't buy "less is better" with acros and light.

 

[__SKINNY__]

8-9 is a good time frame

 

[Gangous]

Reef bass Have u tried shorter cycles or u just don't buy it? I'm thinking of upping my lights hrs back to 7 from 5

 

[t4zalews]

9 hours..I've always had good color and growth with this time frame

 

[smalltime]

2 400w radiums 10 hours and 4 t5 for 12hours

 

[curlykid]

8 hours.

 

[MSHUR]

8 hours

 

[jarrett shark]

i GUEES I AM GOING 8HRS

MSHUR ARE YOU RUNNING 400W OR 250W

 

[s_kelley]

8hrs with two 250w 20 radiums

 

[ros_sco]

7.5 hours 2 x 250 watt

 

[MSHUR]

i GUEES I AM GOING 8HRS

MSHUR ARE YOU RUNNING 400W OR 250W

400w

 

[REEF SMAC]

8 hours.

 

[Reef Bass]

Reef bass Have u tried shorter cycles or u just don't buy it? I'm thinking of upping my lights hrs back to 7 from 5

8 hours is my shorter cycle. I used to run 10 and I had my best color and growth then. I cut back to 8 because of algae issues which I'm slowly beating.

Coral evolved in a tropical environment with equal day and night. So shave an hour or so from each end of 12 hours and you're down to roughly 9-10 of intense full sun. And not just a little bit of light from a small comparatively dim fixture, but full sun. The theory that the bright pigments on the sensitive growing tips closest to the light function as a protective type of sunscreen also makes a great deal of sense to me. Hence more light = more sunscreen = more color. I also run 400w MHs.

 

[tegee]

9 hours for the past 1+ years. Just adjusted back to 7.5 hours last week. Colors were getting pale.

 

[JG1]

Coral evolved in a tropical environment with equal day and night. So shave an hour or so from each end of 12 hours and you're down to roughly 9-10 of intense full sun. And not just a little bit of light from a small comparatively dim fixture, but full sun. The theory that the bright pigments on the sensitive growing tips closest to the light function as a protective type of sunscreen also makes a great deal of sense to me. Hence more light = more sunscreen = more color. I also run 400w MHs.

I've read though that even though corals are accustomed to equal days/nights being close to the equator, that they only receive about 5 hours of intense full sun.