How long do you run your MHs?

[alton]

I had DE lamps that went bad in 8 months. Switched to SE and have never looked back. My Boss has a Giesmann Fixure and lamps and they last over a year before Ken changes them out.

[ErikH]

Hmm, De bulbs are supposed to last 18 months, the same as T5s. I have bulbs that are over a year old @10+ hours per day. Everything else I have read has said that the lifetime of the DE bulbs is much longer than SE. If you are using 400w, that may be the case however as I know Bill had issues with the 400s.

[Bbristow]

Water chemistry would be more of an issue of algea growth than running lights for longer periods of time.

I have always thought this to be the case as well but I don't think this is always the only factor. I was speaking to a guy who has been doing this for years, doing talks around the US on the hobby ect. An expert. He realized that after the corals reach the peak photo exposure any time after that his MHs were feeding algae growth. He dialed the time back on his lights and his algae issues began to dissipate. I am starting to notice the same in my tank the algae growth has slowed and the coral continues to thrive. Maybe a coincidence. Wanted to see if anyone else had tried this. I have dealt with a small amount of hair algae and made all the other changes I can think of before this (change bulb, increase water flow, 20% monthly water changes, phosphate removers, ect.). The shorter photo period seems to be helping, at least in my case.

[Texreefer]

If you have determined the exact par needs of each coral and are measuring the par in your tank and have determined that you are reaching the saturation point this may be true.. but most of us cannot do this and most of us cannot provide enought light to reach the saturation point unless we have unnaturally long photo periods

[Bbristow]

Thanks for chiming in Texreefer. Your Perc-Osc clown is doing well by the way. Thanks again!

[Texreefer]

glad to hear