Metal Halide Q&A

I have a question on mh lighting for my 55gal. I have a home made canopy the lights are at the top giving 15 inches from the bottom of the MH to the to top of the water. There is a peace of glass between the MH and tank to help with the heat problem (water stays about 81 degrees. The current MH system is two Odyssea 150w MH (doube ended) with 4 12in 14w antic t5s. My question is what K should I be using. The system came with 15000k and I switched to 20000k (to blue and coral did not do well lost a clam). Any ideas?

 

It is not so much a function of the color temperature... but more so the quality of the bulb.
The clam could have died from many different reasons, low quality bulbs being one of them and lower wattage bulbs being another.

Since your bulbs are 150w I would say probably radiums if you want to stick with the blue color. Or if you want to go lighter then I would recommend ushio 10k or 14k. I highly suggest that people do not buy crappy bulbs from over-seas because they will kill your corals and make cyano/algae grow.

 

Hi Trent

my new MH are working out really well for me

currently running 10 hours, with lamps suspended approx 14 inches away from water surface
all corals, including LPS are doing fine under this regime - no signs of stress, bleaching or early closing down on LPS corals

would gradually increasing to 12 hours be a good idea
or would lowering the lamps 2 - 4 inches closer to water surface whilst maintaining same light duration be a better idea?

Steve

 

hey Steve, sorry I didnt see your post earlier!

It really is a trade off here... two more hours means less overall bulb life and a bit more to the electricity bill, but two more hours of viewing pleasure

Lowering the lights means more light getting into the tank but also means that the tank temperature might go up a bit :-/

my personal preference here would be lowering the light, but in the end it is all up to you to weigh the pros and cons of each

 

150,250,400 whats the difference on shallow tanks

ok so on my frag tanks I have just simple 150w on 1 of them and an led unit on another doing a growth experiment, but my question would be this....
In the area I live in I've seen many frag tanks the average is about 8-12 inches tall mine being 12 inches thus the 150 w, but I see some people with 8-12 tall tanks with 250 and even 400 watt mh over top of them are they wasting electricity or are they really going to get that much more growth from the higher watt on such shallow tanks?

 

There will be a bit more growth from higher light output... But that will only go to a certain point and then kinda level off. I would suspect that the 250 and 400w guys are doing that because they want better color out of their corals. At least that's why I run higher wattage lights over my frag tank lol

 

just wondering i have a 40 gallon breeder will 1 250 be enough with t5s or should i run 2 250s

 

also hanging is not an option it will have to be leg mounted the tank is 36 inches long 18 wide i think 18 tall

 

I'm running 2 250w 20k halides and I have it about 8" above the water surface, is this a good distance?

 

"Your bulbs will easily keep any corals you want (6500K-10K is for growth, 14k is for looks and okay growth, and 20K is mostly for looks only)"

You said 20k's are for looks only, can SPS still grow under it?