How long should the lights be on?

jeeperrs

jeeperrs

New Member
I am currently putting together a 75 gallon tank and trying to figure out what lighting system i want to go with. I have been reading that a 2 x 150 w MH set would allow me to keep just about anything in my tank but I am not sure how long I should leave the lights on. I don't want to get something that is to strong and will "burn" the corals but that can be on long enough so that I can enjoy the tank when i get home from work. Do you think I could run 300 w MH for 10-11 hrs a day or does it need to be limited to just 8 hrs? Also, I have heard of people using 14K bulbs to have the same affect as half actentic and half 10k bulbs, what do you think?
 
mandarin w

mandarin w

Member
On a standard 75 gallon tank, one that is 4 ft long, the 150 watt really wont give you the penatration needed. A 150 watts is really intended for a tank that is only about 16inches deep. With a 75 gallon you really should be looking at 250 watts. That will give your tank enough penatration to get to the bottom of the tank.
As far as how long the lights should be on. Most go for around 8 hours for the daytime bulbs. But there is no time set in stone as to what time you have to have them come on. If you work an afternoon shift and don't get home until 11pm, Then set you light to come on at 3 or 5. Then the lights will be on for you when you come home. At least the first couple of hours.
 
todj2002

todj2002

Member
i would keep the light schedule eight hours or less. i have had my tank up since about july and i had the lights on for about ten to twelve a day and all i can say is if u like algae and diatoms use that schedule. i have them on six to eight hours now and my tank is crystal clear with no algae or diatoms. they were so bad before i was about to give up on the hobby. i also do not use ro water yet (i plan to when my budget can afford it) i just keep a short light schedule and like i said, crystal clear. my rock is getting some nice pinks and red colors now. before they were covered with hair algae and diatoms. hope this was helpful.
 
badoleross

badoleross

Member
I had a 90 and was running 2/250s for 12 hours a day and didnt have any issues with algae. Pleanty of LR and a fuge with cheato. The tangs didnt hurt either. And snails, just 5-6 mexican turbos.
 
todj2002

todj2002

Member
do u use ro water? people tell me that diatoms feed on silicates in tap water. but i left my lights off for four days when i was about to give up and noticed that the diatoms were going away. now since i keep a short light cylcle i am not having problems.
 
cam78

cam78

Active Member
Does it matter what type of lighting you have? Do certain lights need to be on longer than others? I have PC's and they are on for 11 hours a day. Diatoms are annoying and algae film is always being scraped off the glass by me. I have some coral so that why I leave it on for so long. Suggestions?
 
cam78

cam78

Active Member
I cut my lighting down to 10 hours. That does not mean it is dark in the tank, there is some window light (not direct) is this OK? The diatoms and algae was not going away. Is this to short of lighting for the tank?
 
stanlalee

stanlalee

Active Member
Originally Posted by xDave
Animals from tropical regions need 12 hours of light year round.
I agree 12hrs. If you dont want to run high intensity 12hrs get flourescent supplements and run those in the am/pm. I also think 150w HQIs are plenty enough to penetrate and keep anything in a 75g. If you look at much of the testing you can see just by changing bulbs alone you can have a 150 HQI that puts out twice the PAR of another 150HQI or a 150HQI that puts out more PAR at depth than a 250w HQI with low performing bulb/ballast combo. the difference between 16" and a 20" 75 gallon is within the difference of acceptable placement adjustments for Halides (8 to 12" above the water). 16" would limit 150HQI to nothing but 30 gallon and smaller tanks.
 
jeeperrs

jeeperrs

New Member
That is good to know. I don't mind running the MH 12 hrs a day but I wasn't sure if that was too much light. I probably won't do a "combo" light fixture if I don't have to purchase as that is just energy that it looks like I don't need as of yet. If anyone else has something they would like to add feel free!
 
payton 350

payton 350

Member
just experiment with it.....i prefer 8 hrs.....but if you want 12 then do 12......or start at 8 and every week build up 1 hr until u hit 12.....this way is you start to get an algae outbreak it will be kept to a min.
 
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