do you leave MH lights on all the time

[krazekajin]

I have a PC but I am possibly getting a MH light with PC and Lunar Lights.
Anyway the fixture comes with three cords. so I could have all three lights on seperate schedules.
But I read somewhere that you aren't supposed to turn your MH off and on. So if they stay on all of teh time, what is the purpose of the lunar lights and how do you get your tank into a day/night cycle?
Any suggestions.

 

[exile415]

your not supposeed to leave it on all day, i think they meant don't turn it on and off and on and off

 

[albert7753]

I currently have 2-250w mh's & 1-400w mh in the middle. You don't want to keep them on all day for varouis reasons. bad alge growth.
Metal halides take awhile to turn on so if you turn them off you have to wait a bit to turn them back on.

 

[civileng68]

Right, if you turn off your MH's they wont turn back on for about 15 minutes.
They take about 5 minutes to really turn on all the way.
Also you dont want to keep them on all day for serveral reasons. Algae growth as a previous person said.
Also because of heat. If you think your current lights are warm, you "aint" seen nothing yet.
MH's are so hot, you cannot put your hand directly under them for very long. they will burn your skin just putting them under the light. This heat causes the water to warm significantly. YOu cannot, SHOULD NOT put a MH light over a glass cover. You need it to be over open water.
Also be prepared for lots of evaporation, so you'll need a process to keep replacing pure, clean water in the tank.
My investment in a R/O unit has paid dividends. I dont use it directly in my tank. I wired it into my sink so I can use it for drinking water as well. WELL WORTH IT!

 

[krazekajin]

so would you have the MH on an 8 hour on, 16 hour off, or 8 on 8off
and the same with the PC
Lunur lights on all of the time
?

 

[civileng68]

Originally Posted by KrazeKajin
so would you have the MH on an 8 hour on, 16 hour off, or 8 on 8off
and the same with the PC
Lunur lights on all of the time
?

I run my MH's 8 hours per day (to avoid heat and algae) but run my actinic lighting 1 hour before, all eight hours my MH's are on and one hour after.
So basically I have lights on 10 hours per day but my MH's only 8 of those hours. You'll notice if you leave them on much longer you really have bad algae outbreaks on the glass (even with snails), and will get large heat fluctuations.

 

[mudplayerx]

I keep my MH's on for 8 hours a day. Anything over that might stress the critters or lead to algae growth. Microalgae aren't like plants, which require light, nutrients, C02 all in sufficient doses. Just one overabundant resource (lighting) is enough for microalgae to bloom, regardless if other resources are available or not.

 

[harndog]

I run 260 w pc atinics from 9 until 11 then two 150 w de mh with the atinics until 5 pm then the 2 60 atinics until 7. My corals are growing like crazy my electric bill is less and my water temp does not change much at all. This is on a 75 gallon. You really only need 4 hours but I like to look at things so I chose to run 6 anymore is a waste of energy.