[plecosword]

Hello guys, I was just snooping around again and I was just trying to decide on the color temperature of light that would be appropriate for corals if i decide in to have some in the future.
this tank has 250w, 100000k HM

250w, 130000k HM

250w, 200000k HM
250w, 6500k HM

And here is a comparison of a 20000k HQI and a 14000k HQI


so, comments or what color temperature do you guys prefer?
I reall like the white color but corals like the blue color

[NATIVEVAMAN]

The length of your tank rules out the use of one bulb you will have to have two.Each mh bulb is designed to cover a 2x2 foot square of water surface.Using 2 250 watt bulbs over a tank as shallow as the 55 will certainly make fish soup,they are simply far to hot for that application.In fact if you really have to have mh I would suggest no more than 200 watts total in two bulbs.Many tests have proven that 6500k provides the best coral growth and 20000k the absolute worst.14000k is the stand alone point where no actinic supplimentation is required.

[plecosword]

Good I dont like the blue look of the 20000k, so now it would be 14000k or 12000 or 10000k hmm
well i have decided on 2 fixture, I will be getting either one for sure probably.
Nativeman, would 150w, 2 to 4" above the tank create too much heat in a exact 24" deep tank?

[NATIVEVAMAN]

Mario,I would think that 8 inch's is as close as you would want to get 12 might be better.

[plecosword]

for a 150watts!??! is it really that bad?
It would be 2 of these Current USA Outer Orbit Pendant 1x150w 14K HQI-MH w/ 3 Lunar Lights (Saltwater Aquarium Supplies > Lighting > Fixtures > Metal Halide > Pendants > Double Ended MH )
would it even be enough for a 90g? Im not planing on using a chiler.

[NATIVEVAMAN]

Mario,whatever you do,do it with caution.

[plecosword]

lol You have no idea! I think ill stick with the 14000k if MH. Wish me luck.

[reefnoob1991]

I have a 48" 2x250W 14000k sunpod...sits about 4-6 inches off the water and looks great

[pogodzib]

A 10k bulb is probably the most popular bulb, since it is fairly white and give good coral growth. 14k bulbs usually have a much lower growth rate, but the bulbs do have a nice blue hue to them. Typically, you'll want to keep your MH bulbs 8"+ off the water if it doesn't have a glass shield and around 4" if it has a shield.

[plecosword]

yes with this fixture i will have to use glass canopies, so your saying 4"?

brandon, do you use a chiller?

[pogodzib]

Yes, I recommend 4" when you have glass build into the lighting unit, since it traps some of the heat inside the unit there doesn't get quit as much heat directed at the tank and glass blocks light. Clean glass blocks roughly 10% of the light produced, whereas dirty glass can be much higher so you won't want your halides to be as far away since there is less light getting out of the fixture.

[plecosword]

This just gives me another reason to hate hetal halides, This is why I like T-5 so much, last longer, and just better. by the way, I would not need a chiller if i had a 6x54 t-5 fixture would i?

[reefnoob1991]

I need no chiller the water never heats up above 81 degrees and there is glass on each one that i clean regularly

[plecosword]

isnt 81 a bit hot? i mean during summer, its gottta raise up to 84, do sw fish tolerate that? I keep my fw tanks up to 82 for breeding purposes.

[reefnoob1991]

78-82 is ideal.

[NATIVEVAMAN]

If I had to pick a perfect temperature I think it would be 80 degree's.Is there a real chance that this one temp can be maintained for an extended period of time?I dont think so,even if that extended period of time is 24 hours.To many dynamics come into play.You have to mention a few,heat from lights,heaters,pumps,fric tion from water moving thru pipes,ambient temperature,even the location of the tank respective to heat registers.Without the use of a chiller there seems to be little besides fans that we can do to control higher temps.If a tank seems to want to be 80 degrees for a high temp then I would use heaters to control the lower temp and keep it as close to 80 degrees as possable.What we want to prevent is short term temp swings of more than 3 maybe 4 degree's.In an hour a 4 degree temp swing is a bad thing,in 24 hours it is meaningless.Finding a balance between all of these factors is sometimes difficult but there is a balance.The best time to find this balance is best acheived during the cycle when it doesnt effect any critters.

[plecosword]

Ya I was going to play with the temperature during cycle! fw can have fast temperature changes and be fine, how about sw? how slow would a temperature change have to be for them to tolerate it?

[ChehalisCoral]

I like the 14000k

[plecosword]

oh 14000k? hmm How would a 65000k work with corals?

[NATIVEVAMAN]

tests have proven the 6500k are just about the best around for coral growth.Unfortunately they give a dull look to the tank.14000k mixed with actinics will give very good growth and a nice look to the tank.

[plecosword]

oh, I keep forgetting sorry, are actinic blue or white?
That would be nice, to have 6 different color temperatures in 1 fixture. I have 65000k in my 20 gallon and half of my 55g, and it does look kind of dull.

[NATIVEVAMAN]

They are blue.I dont think I would try 6 different bulbs.1/2 14k and 1/2 actinic will work just fine.

[plecosword]

well thats kind of what I meant. Is are Actinics the blue ones?

[NATIVEVAMAN]

Yes they are blue.