Heat output 14k vs 20k MH?

[Catawaba]

Hi. It's time for my weekly dumb question. Would a 20k MH bulb put off as much heat as a 14k?

THANKS

[GSMguy]

could be less depends on the bulb,

are you trying to fix an overheating problem?

[J. Montgomery]

Maybe I'm missing something, but wouldn't the heat output be more related to the wattage than the color spectrum of the bulb?

[Catawaba]

Yes and no. I'd like more color AND I'm struggling a bit with heat.

[Catawaba]

<a href=showthread.php?s=&postid=10492010#post10492010 target=_blank>Originally posted</a> by J. Montgomery
Maybe I'm missing something, but wouldn't the heat output be more related to the wattage than the color spectrum of the bulb?

I agree with wattage, but am thinking that a 20k burns 'cooler' because of the 'cooler' appearance....don't know.

On a side note, does anyone ever run 20k MH and 10k VHO?

[DarG]

I've used whiter T5 lamps to take some of the blue out of a halide lamp. Generally it's the other way around but either one would work. You're probably better off getting most of the par out of the halide and the color supplementation from the flourescents but it works the other way around from a color perspective.

On the heat issue, I dont think the color would have that much to do with it. The bulbs and the ballast could though. Some bulbs draw more current than others from the ballast, they run at a slightly higher wattage. So, also depending on the ballast, if the 20K 250 watt is running at 300 watts and a 14K at 250 watts, the 20K would probably put out more heat. But it could swing the other way too, depending on the particular bulb.
But bulbs can run on lower wattages on electronic ballasts vs magnetic. For example, a 20K DE 250 watt may be at 250 watts on an e-ballast but on a magnetic HQI the same bulb could be drawing 300 watts. It's probably less of a swing on electronic ballast though. DE 250 watt bulbs as example again ... the electronic ballasts seem to drive them all very close to 250 watts, still with some + and - but not near as much of a potential swing as with a magnetic ballast which can swing somewhere from 260 - 360 watts for M80 HQI ballast, depending on the bulb.

So, it depends.

[GSMguy]

i dont think bulb switching will help with heat

[Catawaba]

Understood. Running Hamilton 14k's 250w x 2 on a magnetic ballast....have 15k XM's on the way.
Was just a thought.
THANKS ALL

[dhnguyen]

Let me guess... You have an enclosed hood right? Try adding a small fan or two blowing across the tank.

[luke33]

Ive ran 14 and 10 and 20k's and all you need is a fan and you don't have to worry about heat imo. Although an open back helps. I have a clip on 6" fan blowing on my 250w halides, no heat issues, but it does evaporate like crazy....but water is cheaper than a chiller

[Catawaba]

I have a fan blowing across the back of the hood (which is open in back) and have the front doors propped open a bit....Still running around 86. 75g tank, out of direct sunlight, 1 tunze, 1 seio, one MJ 1200 in tank. One MJ 400 in sump to feed PhosBan reactor, and one MJ 1200 in sump to feed skimmer. Sump pump is external. 220w VHO's on for 8 hours, 500w MH on for 5 hours each/they overlap by 2 hours, so both bulbs are on for 3 hours. I add at least a gallon/day in top off.

[dhnguyen]

How large is your sump pump? What size is the SEIO?

D.

[Catawaba]

Will have to look at them...bought the system as a complete unit.

[Catawaba]

SEIO is the 1100 and the external sump pump is GenX 30.....Puts out about 900gph w/zero head. Anyway, I think I'm getting a handle on it.

[luke33]

How close to the water are your MH's? If there 6" or closer it could be the prob.

[HaroldT]

There should be no difference in the heat output of the MH bulb regardless of the Kelvin (20K, 10K, etc) unless you use a different watt level.

[DarG]

<a href=showthread.php?s=&postid=10501233#post10501233 target=_blank>Originally posted</a> by HaroldT
There should be no difference in the heat output of the MH bulb regardless of the Kelvin (20K, 10K, etc) unless you use a different watt level.

I agree, the differences in actual wattage between different bulbs of the same nominal wattage rating, in reference to my above description, probably isnt enough to make a signifigant difference in the temperature in your tank.
It could ... if your ballast is actually running your two x 250 watt bulbs at 320 watts each and the two new bulbs end up drawing 270 watts each, you have a 100 degree difference. That difference does translate into less heat but I doubt you are talking about anything signifigant in the tank itself. Maybe if different bulb pairs are at completely opposite ends of the actual wattage range ...

My dual 250 watt system runs the chiller more than my dual 150 watt system did but we are talking about signifigantly larger power differences there than we are with differences between different bulbs of the same wattage category.

[dhnguyen]

Well one thing you COULD do is run 20K and get rid of the 220W VHO altogether. That's A LOT of heat for what basically amount to aesthetics (actinic) only

[dhnguyen]

Also why are you using such a large pump for a return? 900gph seems a bit excessive for a 135g IMO.