Can Metal Halide lighting be on 24/7? It just came into my mind. I saw people have frag tanks to help pay for their actual tank, but would it be possible to move lighting around from one tank to the other, morning and night? Just wondering haha.
Thought of another question. On a frag tank with no fish, would water changes be used only to replenish calcium and stuff or does coral give off some waste?

not sure if they can, but the bulbs wouldnt last as long probably

haha ya, at least you don't have to buy 2 systems. just 2 bulbs i guess

proly could. but you would burn it out very quickly. might become a hassle.

yes, corals poop, they eat and release small amounts of waste, but they do and also shed bits of old tissue. its really small, stick to regular water changes if it makes you more comfortable.

I see. So 24/7 operation probably won't be cracking breaking shattering the bulb. Thanks. Just curious haha

Just think of it like this....would you drive your car 24/7 without rest? MH are less efficient as the temp rises. Instead of possibly shortening the lives of your bulb and ballast, get a second system or possible a T5 system. Your wallet will thank you in the long run.

Steve,

I think that's a good question about the 24hr lighting. If you had a dedicated Halide over one tank or of frags for example...the light itself could be run for 24hr periods. You would just have to keep track of the hours you put on the bulb. IMO on the larger halide fixtures 400 W + the wear is in the start up of the lamp. Shutting them off and on leads to deterioration. I wouldn't equate lighting deterioration to driving a car. A car is a complex machine, a light is a bulb and a ballast pushing it. You could always get a light meter to check your PAR/Lumen output if it's something you wanted to try.

I'm not sure how much light corals can stand. It stands to reason if you wanted to grow them out more quickly you'd want to give the most hours of light they could stand without stressing them out. 10 - 12 more?

I'd like to know roughly how many hours of light corals can stand since I'm considering setting up my own Frag tank to help cover costs. I realize that it could vary widely among the varieties but if someone has experience in aquaculture, I just need something general.

Here is a good site on aquaculture in detail.

It covers sizing the type of light and output of light for tanks of a larger scale.

corals being living creatures who's lives are directly affected by the suns photo=period, I imagine, would enjoy said photo-period.

corals need a photoperiod.

Thanks, I figured as much but what's the limits? I've read that some corals do not like MH lighting when put under it but it's because it was used to HO Flouro, they do acclimate if care is taken though.

So what's the max length of photo period to coral? I know that living things such as plants and humans supposedly need a photo period as well, however this can be cheated in certain instances. Plants can be put into a straight 24hr light regimen, or 18hr on 6 off if 24 is to stressful.

Think about what lighting corals receive in real reefs. The sun isn't up all day, and increased photoperiod isn't beneficial as corals do other things at night. Corals are animals, not plants. Moreover, algae will grow quickly under such conditions.

I just find it hard to believe that they wouldn't do better under longer lighting conditions. It appears that they do better under higher Wattage once acclimatized. What do they do at night that they couldn't do in a few hours...say 6 for instance. Digest food? Metabolize that food? Transform that food to growth, and energy? Why would they not benefit from taking in more with an increased photo-period?

I don't mean to be difficult, I just can't believe it. I'd like to see a paper that has been published stating that they do not benefit from increased daylight.

http://www.advancedaquarist.com/2009/5/aafeature

for my frag tank and rubbermaid bucket filled with freshwater shrimp and moss, i put my 4x24watt t5's over the freshwater tank from 7 till 3 and i put it over my frag tank from 3-10 and it works great.

I can't direct you to a paper on coral but I do know that algae and other plant life typically benefit from dark periods for so called "dark reactions". These are growing periods and allow time to repair from damage, etc. I can image that it is the same with corals. Like, you couldn't be in the sun 24/7... you'd toast...

You could likely extend your photoperiod longer and longer and go for that steroid effect, but you will likely compromise their health and they will be more susceptible to issues. Corals have done pretty good for a few million years with what nature gave them; the closer you can copy nature, to certain extents, the happier they will be.

Then again, someone needs to experiment and publish the results of extended photoperiods. Give it a go if you are brave and be careful. Let us know how it goes!

if your looking to cover to tank and dont want to spend the $$ on a second light. what you can do is get a light rail. the light rail will move the light back and forth from one tank to another. what you can do is have PC or T5 light on your tank and have the MH be hanging on the rail and move from tank to frag tank or which ever tank your running. that way you dont have to keep the light on 24/7. check with wetthumbfrag for light rail if your interest.