Home Made Mh Unit

Finally the opportunity has come up for me to be able to build my own MH unit cheap (working for a local lighting authority has its plus side), before I get the balast and gear needed I was just windering what Kevin lamps to go with, I have decided to go with 2 x 150w MH with 2 x t5 blue, while I have upto 600w MH available I am considering my electric bill!!!!!

I prefer the crisper white of around 14,000K although im not sure this is the best option to go with when using MH lighting?

luckily our nominated cotractors also have a fabrication shop which means I can pretty much design the unit as I want ( and will cost me peanuts! ), reflectors will come from redundant street lights which will be ideal for this purpose due to thier even (depending on which light i nick it from) light spread with very little light spill, my only other concern is the glass to cover the MH tubes and reflectors as I am unsure if the temp will cause a problem, so any advice on this would be good.

6500K is reportedly the best all-round. The diverse mix of halides takes years to exhaust, and the spectrum is optimal, especially for corals closest to the surface in nature (many Acropora, Sarcophyton elegans). But they, in my opinion, aren't the best looking, and don't seem to bring out coral colours as much as bluer spectra. If you have actinics they should balance it out quite nicely.

>10000K looks bluer, but the less diverse mix of halides burns out much quicker than in the 6500K. Is it worth it? My personal favorite is the 10000K as it appears to be somewhat of a compromise. Too blue and you lose PAR fast... keep that in mind.

I personally have never had any problems with temperature. My halide is 5'' above the water and has a nice big fan to keep things cool. Unfortunately the temp can actually drop by several degrees during the day because of the evaporation.

Lastly... dude, you are one lucky bastard.

Yeah, wicked lucky. I personally love the color of a Hamilton 14K bulb, and they do not seem to burn through phosphors that quickly at all. Dunno if they make them in double-ended varieties though

Ski I can get them in double ended over here (not much they cant get on request ) besides if they only last a few months i'll just ask them to get a few extras! while im at it.

Lynden thanks for the info will make sure i incorporate cooling fans anyway and will make sure the unit is vented to keep it cool

and yep i am one lucky bastard!!!!!!!!!! will take a while to get it sorted but should be worht the wait

don't worry about the blue T5s as you get plenty of blue light from a decent halide. You didn't mention what you are keeping, I gather its a coral tank. How big is the tank? If the tank is 6x2x2ft then 3 x 150w halides would be fine. 3 x 250w would be more than ample to grow anything in that size tank. If the tank is 3ft tall then go for a higher wattage. Don't bother going over 400w though because the corals don't need it and neither will your wallet. You generally have one metal halide unit for every 2ft square.
As mentioned above get globes with a 10,000Kelvin rating. 14,000K are a bit blue and don't look right. 6,500K don't have enough blue. 10,000K is about right, the light looks bright and white but has good colour for corals.

the tank is 39" x 18" x 18" so 2 x 150w will be fine for what i want, also would like to keep the blues as like seeing it at night before lights out completely.
I'm looking anywhere between 10,000k and 14,000k and seeing what turns up and will plan from there, incidentally for thos that want a good laugh the storeman thats looking for this type of lamp thought he had cracked it and found what I wanted only to realise it was a little to high powered and to many K, this is the best bit it turns out the lamp was 1800w and 155,000K yes 155,000K what in gods name needs to be brighter than the sun! 8) and can you imagin my electric bill!!!!!

You usually only get 10,000, 14,000 or 20,000K globes above the daylight spectrum. I don't think you will find anything in bewteen 10 & 14. Most 14,000s have too much blue and don't look as bright or clear as a 10,000K.

You will probably only need 1 blue T5 for the tank. A lot of people use them at night as it allows you to see the nocturnal creatures come out to play.

The local Bunning stores have 1000watt globes in the ceiling. I heard of a store that had 2000watt globes in their ceiling as well. It was a supermarket store from memory. Not sure about the 155,000K. Maybe 15,500K. 1800watts is a pretty intense globe tho. Anyone got a spare nuclear reactor I can use to run my fish tank

I can't wait until the high output LED lights are cheaper and more readily available. They will produce as much light as a halide but use virtually no power. They better hurry up and make them for me.

sorry to but in on the post but ive made myself a DIY MH unit using an outside halogen light fitting and adapted it to take a 150 watt double ended bulb. Then i simpy got an external gearbox to power the bulb......think it cost me about £45 total including the bulb.

However i cannot work out why colour of the light seems to be nothing like what ive seen in pictures on the internet and on tanks at my LFS. Therer are 2 tanks in particular at my LFS where the light is so crisp and white and its using 2 x 250 watt 10000K bulbs, Whereas my tank i have got a 1 x 150 watt bulb rated at 20000k and my light doesnt look blue at all it still seems to have a hint of yellow to it would there be any obvious reasons to why it looks like it does in the picture below. O and forgot to mention the bulb is only about 3 months old.

20,000K would go the opposite from blue towards what looks like the yellow end of the spectrum, the output is not done on the Kelvin of the lamp that just determins the colour, the wattage will determin how powerfull the light source is and how deep/far it will be effective, to complicate matters more part of the output is measured using a lux measurement then to measure it on the ground there is illuminance and luminance, depends on the application your measuring as to which would be of use.

In short even though your LFS are using 2 x 10000k lamps this does not mean the overal kelvin should be a sum of both, thier Kelvin will still only be 10000k so in order to obtain the same colour you would neet to change the lamp to a 10000k one, hope this makes sense and my first part hasnt confused you.

20,000K is blue light. If your globe is yellow then it is about 3,000K.
The globes made by different companies will also vary in how they actually look. In my LFS they have 3 different brands of globes and each brand produces a different coloured light compared to the others in the equivilent Kelvin rating. it's really quite incredible the difference bewteen them.

So your saying i may have to go for a different brand of bulb then yes??? would u reccomend any brands to me??

Before i made this unit i had another metal halide unit that had the starter and everything build into the unit and they said in the shop this had a 10000k bulb in it and when i turned it on i was horrified by the colour i sadly aint got the picture of it anymore but the bulb must of been dodgey as it was more yellow than car headlights but anyways the whole let went back and i made my own.

Hi craigbaby37

yep if you're running a 20,000K globe it will look blue, not white. Everything in your tank will have a blue tinge to it and probably look dull and gloomy.
If you buy a $5 globe from a hardware it will be a 3 - 4,000K globe. To get a descent globe go to the petshop, hydroponic shop or a lighting specialist.
A 10,000K globe should give you a bright white light.

ok thanks for that i think ill give a 10k bulb a try and see what happens........however i realy cant work out whats up with the 20k ime running atm as it doesnt have a blue tinge to it all all..................when the light turns on yea it goes very blue and almost UV colour then goes to the yellow/white colour. o well ill see what luck i get with the new bulb.

your 20,000K could be a dodgy bulb, or it might only be a 10 or 14,000K and someone got the pack messed up. It should be written on the actual globe.
Any idea how old it is?

I would not recommend a blue T5 actinic for a night light on a reef tank. Any diver will tell you how quickly the red, orange and yellow light is absorbed by water, leaving anything from around 15m down with a very blue tinge. As a result of this, most reef fish see extremely well in the blue range and very poorly in the red range.

If you truly want to see a nocturnal tank use red light.

Also, quite a few manufacturers offer 12,000K bulbs. These are a nice go between from the 10 to 14k