Crisp white light like no other, bringing out colours and making everything look sharp. Bright light punched down through the water to the plants or corals that need it most. Breathtaking, shimmery lines glimmering over the substrate. Ahhhhh, the serenity. Cripes! What's that? A £400 price tag!!!! WHAT DO YOU THINK I AM, A BANK???
The good news is: Metal halide lighting doesn't have to cost that much. That's right. Go into your nearest supermarket or warehouse..... and look up. What can you see? Most likely, lots and lots of metal halide lights. You think they cost £400 a piece? Not likely.
Yep, metal halide lighting can easily be built. Using the same components as more expensive units. Cheaply. In this post, I'll point you in the right direction, and introduce how to DIY a double-ended (commonly inappropriately singled out as "HQI") metal halide fixture of 70W or 150W, that will make your tank look so good, your eyes will bleed and fall out of your sockets. In a pleasant way, of course.
So, what do we need?
1. A lamp
Do you want the good news or the bad news?
OK then, bad news first: This is where you're going to have to bite the bullet. Yep, first item on the list -- and it's an expensive one. Y'see, those industrial bulbs you see everywhere are not the right spectrum for most tanks. Plants might be OK with them.... but the yellow colour caste would be pretty unappealing to the eye.
There is some good news though -- metal halide bulbs are starting to come down in price. There are a number of brands which - when you consider the increased life of halides over fluorescent bulbs - actually work out cheaper than the equivalent wattage in old-skool tubes. And some of them are good. Guess what? We stock some that we like and use ourselves... and they're the cheapest you're likely to find in the UK. But this isn't supposed to be a sales pitch.... (psst... only £19)
2. A ballast
Just like standard fluorescents, all metal halide bulbs require a ballast to run. The ballast limits the current flowing into the bulb, stopping it from drawing too much, overheating, and creating a giant black hole that sucks up the entire solar system.
Fancy electronic ballasts are quiet, cool-running, wonderful pieces of electronics artwork that can also clean your shoes, repair broken marriages and make you immortal. They can also cost a small fortune. This will change before long, as manufacturers learn how to (pay to) comply with the EU's electromagnetic interference directives. But, for now, they can be expensive.
We won't be using them, of course.
Magnetic (core and coil) ballasts are the bread and butter of the lighting trade. Reliable, sturdy, heavy as a brick, and can keep your house warm in winter. But they also tend to run most double ended bulbs a little brighter, which is a big plus. Most magnetic ballasts that we can use are dual-purpose - they can fire mercury vapour or metal halide bulbs. Choose one from a lighting stalwart such as Philips or Thorn. We do not stock them (yet), but you can find them for sale all over electrical stores, eBay, and many other places.
Double-ended metal halides are all "pulse start" bulbs. This means they need a high, pulsed starting voltage to start up. A core and coil ballast can't do this on its own -- it needs a small component called an ignitor to do this. Upon start-up, an ignitor supplies the bulb with the gazillions of volts it needs.
A halide also tends to mess up your mains voltage waveform -- a nice sinusoidal (supposedly) wave comes in -- a nasty tattered mess of a waveform, that may cause undesirable operation in nearby electronic equipment, comes out. This is easily fixed with a capacitor bridging the live and neutral wires before the ballast. The exact value of the capacitor needed varies depending on the ballast, but is usually 18 - 20 microFarads (also rated to 250 or 120 V, depending on where you live). Chose one which can withstand high temperatures -- 100 deg. Celsius is best, but 80 degrees will work.
The ballast will need to be matched in terms of wattage to your chosen bulb (i.e., 70W, 150W or 250W, for double-ended bulbs). Ignitors usually specify a range of wattages they are good for.
The good news here is that the three components often come together, pre-assembled. If they don't, then you can easily follow the connection diagram which is almost ubiquitously silkscreened on top of the ballast. If you've ever wired up a standard fluorescent fixture, then this will not be new - the difference is that you'll want to be using decent wire of at least 0.75 sq.mm cross-section - wire from a 10A extension cord will do the trick nicely.
A run-of-the-mill 250W ballast for metal halide or mercury vapour. The connection diagram is provided.
I'f you're in the US, things are a bit different. I'm going to cop out a bit here and instead provide you with the best link ever about which (US) ballast to choose.
If you do want to buy the components separately, lighting contractor outlet stores will be able to help you. Don't be surprised if the ballast comes looking like it has been bounced off walls. They all look like that. Really.
If your ballast didn't come as one part, or if the parts were not mounted in a box, then you'll need a ballast box, too. A sturdy metal box can be had from pretty much any electrical or electronics outlet. The box will get hot, so be careful where you put it. Mount everything firmly inside with screws - the ballast mounts to the bottom, and the capacitor and ignitor mount horizontally on their integrated bolts. Make a secure, screw connection to ground/earth inside the box.
3. A fixture
This is the expensive part in many store-bought halide systems. This is because they are made from prized aluminium mined by dwarves in the Himalayas, and then finely hand-crafted by Santa's elves.
Well, at least they should be, given their price point.
This is where we can really save some of our hard-earned cash. You could buy a cheap-ish, ugly floodlight fixture - complete with ballast - for around £50 on eBay, but where's the fun in that?
If you go to the lighting section of your hardware/DIY store, they will likely have a fine range of halogen "worklights". With your prized bulb in your hand, choose a halogen fixture that the bulb will fit in. For my lights, I used a 500W halogen fixture from my local B&Q. It cost me under £10.
Rugged, watrerproof, and not too shabby looking. With change from a tenner. Just make sure the glass cover is intact.
Take the fixture and gut it. Oh yes.... I almost forgot... pay for it first. Then go home. Then gut it. Yes... That's the right order.
These fixtures are designed for the heat thrown off by a halogen light, and so should have no problem coping with the heat from our halide bulb.
Keep the reflector inside, but remove the halogen bulb and socket. Keep the glass. This would be a good time to point out that the glass on these fixtures is absolutely mandatory. Double-ended bulbs produce a good deal of UV radiation, that will not only kill your fish, plants and corals, but will make you blind or even kill you in short order. Standard glass (tempered is best as it gets toasty) should block most of this. This is serious *NEVER* operate a double ended bulb without a glass cover firmly in place.
Some people on the 'net recommend grinding down the sockets in the halogen fixture to accommodate a halide bulb... sometimes, 70W bulbs slip straight in. However not in MY house. No way.....
4. Lamp holders
These can be had very cheaply. And it is worth it. My advice would be not to take the cheapskate option and use or modify a halogen socket. These things are produced with tight tolerances and with specific... er... specifications. For example, they take into account how much the material will expand when the ferociously hot halide bulb is on. Don't skimp.
70W and 150W double-ended sockets are the same, just differently spaced. If you can find it, I would recommend sockets already screwed into an appropriate spacer bar -- it makes it easier to judge how far apart they should be spaced to hold the bulb correctly. Electronics and DIY shops on the 'net sell such bulbholders. We will be stocking such sockets on our website shortly... but if you need some urgently, then give us a shout and we'll send some on for you.
5. Some wire
10A extension cord will do just fine for the input to the ballast. Do remember to put an appropriate fuse somewhere along the path -- in the plug in the UK, or mounted in the ballast box in other countries.
I have also used such wire to connect the fixture to the ballast, without any issues. However, I can't recommend this as best practice. You really should get wire with insulation rated for the high-voltage start-up draw of the bulb. High temperature insulation is also another factor to consider. Normal 10A extension cord may not be properly rated for a high voltage supply. Regardless, such wire can be easily ordered.
Make sure you also run a ground wire from the ballast to the fixture, and ground the fixture using the screw mount provided.
One last thing you need.... an ingenious plan...
Your fixture will get quite hot. You will need to figure out a way to mount it. Enclosing it in a small wooden canopy may not be the brightest idea. Many people do this, and rely on fans to keep the temperature down. I also use a fan, but I don't use it as a last line of defence between success and my flat burning down. At least, not intentionally. Hanging these securely above the tank, or using metal supports (see mine below - I used metal shelving supports) should be fine. Resting them directly on wood may be OK, but it's your call.
I should point out that I absolutely cannot take any responsibility for damage, loss of life, money, toenails, spouses, or anything else from following or not following my directions or incessant ramblings. As with everything you read on the 'net, treat everything with a healthy dose of scepticism and make your own decisions. And don't run with scissors...
And there you have it! Easy stuff. For reference, I built a 150W halide for my nano-reef for well under £40 (excluding bulb... which I .. ahem.. pilfered.. from my own stock), which included a pretty all-in-one ballast. All my future tanks -- even freshwater, will use halides. Heck, they're so cheap, I'm going to make special fixtures to hang off my cats to help them see. I like them so much, people will point and call me Halide Weirdo, and cross the street to avoid me.
Links
Links to other people who have performed similar DIY and might still be alive (many more can be found by searching for "Regent" and "Retrofit":
1. 2. 3. 4. 5. 6.
My lights:
The fixture (turned off):
The result:
The good news is: Metal halide lighting doesn't have to cost that much. That's right. Go into your nearest supermarket or warehouse..... and look up. What can you see? Most likely, lots and lots of metal halide lights. You think they cost £400 a piece? Not likely.
Yep, metal halide lighting can easily be built. Using the same components as more expensive units. Cheaply. In this post, I'll point you in the right direction, and introduce how to DIY a double-ended (commonly inappropriately singled out as "HQI") metal halide fixture of 70W or 150W, that will make your tank look so good, your eyes will bleed and fall out of your sockets. In a pleasant way, of course.
So, what do we need?
1. A lamp
Do you want the good news or the bad news?
OK then, bad news first: This is where you're going to have to bite the bullet. Yep, first item on the list -- and it's an expensive one. Y'see, those industrial bulbs you see everywhere are not the right spectrum for most tanks. Plants might be OK with them.... but the yellow colour caste would be pretty unappealing to the eye.
There is some good news though -- metal halide bulbs are starting to come down in price. There are a number of brands which - when you consider the increased life of halides over fluorescent bulbs - actually work out cheaper than the equivalent wattage in old-skool tubes. And some of them are good. Guess what? We stock some that we like and use ourselves... and they're the cheapest you're likely to find in the UK. But this isn't supposed to be a sales pitch.... (psst... only £19)
2. A ballast
Just like standard fluorescents, all metal halide bulbs require a ballast to run. The ballast limits the current flowing into the bulb, stopping it from drawing too much, overheating, and creating a giant black hole that sucks up the entire solar system.
Fancy electronic ballasts are quiet, cool-running, wonderful pieces of electronics artwork that can also clean your shoes, repair broken marriages and make you immortal. They can also cost a small fortune. This will change before long, as manufacturers learn how to (pay to) comply with the EU's electromagnetic interference directives. But, for now, they can be expensive.
We won't be using them, of course.
Magnetic (core and coil) ballasts are the bread and butter of the lighting trade. Reliable, sturdy, heavy as a brick, and can keep your house warm in winter. But they also tend to run most double ended bulbs a little brighter, which is a big plus. Most magnetic ballasts that we can use are dual-purpose - they can fire mercury vapour or metal halide bulbs. Choose one from a lighting stalwart such as Philips or Thorn. We do not stock them (yet), but you can find them for sale all over electrical stores, eBay, and many other places.
Double-ended metal halides are all "pulse start" bulbs. This means they need a high, pulsed starting voltage to start up. A core and coil ballast can't do this on its own -- it needs a small component called an ignitor to do this. Upon start-up, an ignitor supplies the bulb with the gazillions of volts it needs.
A halide also tends to mess up your mains voltage waveform -- a nice sinusoidal (supposedly) wave comes in -- a nasty tattered mess of a waveform, that may cause undesirable operation in nearby electronic equipment, comes out. This is easily fixed with a capacitor bridging the live and neutral wires before the ballast. The exact value of the capacitor needed varies depending on the ballast, but is usually 18 - 20 microFarads (also rated to 250 or 120 V, depending on where you live). Chose one which can withstand high temperatures -- 100 deg. Celsius is best, but 80 degrees will work.
The ballast will need to be matched in terms of wattage to your chosen bulb (i.e., 70W, 150W or 250W, for double-ended bulbs). Ignitors usually specify a range of wattages they are good for.
The good news here is that the three components often come together, pre-assembled. If they don't, then you can easily follow the connection diagram which is almost ubiquitously silkscreened on top of the ballast. If you've ever wired up a standard fluorescent fixture, then this will not be new - the difference is that you'll want to be using decent wire of at least 0.75 sq.mm cross-section - wire from a 10A extension cord will do the trick nicely.
A run-of-the-mill 250W ballast for metal halide or mercury vapour. The connection diagram is provided.
I'f you're in the US, things are a bit different. I'm going to cop out a bit here and instead provide you with the best link ever about which (US) ballast to choose.
If you do want to buy the components separately, lighting contractor outlet stores will be able to help you. Don't be surprised if the ballast comes looking like it has been bounced off walls. They all look like that. Really.
If your ballast didn't come as one part, or if the parts were not mounted in a box, then you'll need a ballast box, too. A sturdy metal box can be had from pretty much any electrical or electronics outlet. The box will get hot, so be careful where you put it. Mount everything firmly inside with screws - the ballast mounts to the bottom, and the capacitor and ignitor mount horizontally on their integrated bolts. Make a secure, screw connection to ground/earth inside the box.
3. A fixture
This is the expensive part in many store-bought halide systems. This is because they are made from prized aluminium mined by dwarves in the Himalayas, and then finely hand-crafted by Santa's elves.
Well, at least they should be, given their price point.
This is where we can really save some of our hard-earned cash. You could buy a cheap-ish, ugly floodlight fixture - complete with ballast - for around £50 on eBay, but where's the fun in that?
If you go to the lighting section of your hardware/DIY store, they will likely have a fine range of halogen "worklights". With your prized bulb in your hand, choose a halogen fixture that the bulb will fit in. For my lights, I used a 500W halogen fixture from my local B&Q. It cost me under £10.
Rugged, watrerproof, and not too shabby looking. With change from a tenner. Just make sure the glass cover is intact.
Take the fixture and gut it. Oh yes.... I almost forgot... pay for it first. Then go home. Then gut it. Yes... That's the right order.
These fixtures are designed for the heat thrown off by a halogen light, and so should have no problem coping with the heat from our halide bulb.
Keep the reflector inside, but remove the halogen bulb and socket. Keep the glass. This would be a good time to point out that the glass on these fixtures is absolutely mandatory. Double-ended bulbs produce a good deal of UV radiation, that will not only kill your fish, plants and corals, but will make you blind or even kill you in short order. Standard glass (tempered is best as it gets toasty) should block most of this. This is serious *NEVER* operate a double ended bulb without a glass cover firmly in place.
Some people on the 'net recommend grinding down the sockets in the halogen fixture to accommodate a halide bulb... sometimes, 70W bulbs slip straight in. However not in MY house. No way.....
4. Lamp holders
These can be had very cheaply. And it is worth it. My advice would be not to take the cheapskate option and use or modify a halogen socket. These things are produced with tight tolerances and with specific... er... specifications. For example, they take into account how much the material will expand when the ferociously hot halide bulb is on. Don't skimp.
70W and 150W double-ended sockets are the same, just differently spaced. If you can find it, I would recommend sockets already screwed into an appropriate spacer bar -- it makes it easier to judge how far apart they should be spaced to hold the bulb correctly. Electronics and DIY shops on the 'net sell such bulbholders. We will be stocking such sockets on our website shortly... but if you need some urgently, then give us a shout and we'll send some on for you.
5. Some wire
10A extension cord will do just fine for the input to the ballast. Do remember to put an appropriate fuse somewhere along the path -- in the plug in the UK, or mounted in the ballast box in other countries.
I have also used such wire to connect the fixture to the ballast, without any issues. However, I can't recommend this as best practice. You really should get wire with insulation rated for the high-voltage start-up draw of the bulb. High temperature insulation is also another factor to consider. Normal 10A extension cord may not be properly rated for a high voltage supply. Regardless, such wire can be easily ordered.
Make sure you also run a ground wire from the ballast to the fixture, and ground the fixture using the screw mount provided.
One last thing you need.... an ingenious plan...
Your fixture will get quite hot. You will need to figure out a way to mount it. Enclosing it in a small wooden canopy may not be the brightest idea. Many people do this, and rely on fans to keep the temperature down. I also use a fan, but I don't use it as a last line of defence between success and my flat burning down. At least, not intentionally. Hanging these securely above the tank, or using metal supports (see mine below - I used metal shelving supports) should be fine. Resting them directly on wood may be OK, but it's your call.
I should point out that I absolutely cannot take any responsibility for damage, loss of life, money, toenails, spouses, or anything else from following or not following my directions or incessant ramblings. As with everything you read on the 'net, treat everything with a healthy dose of scepticism and make your own decisions. And don't run with scissors...
And there you have it! Easy stuff. For reference, I built a 150W halide for my nano-reef for well under £40 (excluding bulb... which I .. ahem.. pilfered.. from my own stock), which included a pretty all-in-one ballast. All my future tanks -- even freshwater, will use halides. Heck, they're so cheap, I'm going to make special fixtures to hang off my cats to help them see. I like them so much, people will point and call me Halide Weirdo, and cross the street to avoid me.
Links
Links to other people who have performed similar DIY and might still be alive (many more can be found by searching for "Regent" and "Retrofit":
1. 2. 3. 4. 5. 6.
My lights:
The fixture (turned off):
The result:
I think you should stress any wiring and dealing with electricity can be lethal, especially dealing with MH and the SW hobby. Any in-experienced person with no knowledge of wiring or electrical know how should get a qualified technition to wire their ballast etc. for them, and not attempt DIY. Thats my opinion of course, and it doesnt suit your whole "DIY your own MH" plan, but I think its sensible to warn reefers or fishkeepers before they begin.
