250w mh = 250w mh (ballast?)

[justDIY]

well, I've educated myself on nearly all aspects of fluorescent lighting, but HID seems to be another ball-park entirely, so I need some tips from those who've done it already!

I have a real bad 'itch' to have an open-top tank, to try growing emersed plants as well as increase O2 exchange with the atmosphere

fluorescent, being soooo very difuse doesn't seem well-intended for this purpose, since the higher the lights above the tank, the more light spills onto the walls / floor / anywhere but into the tank

so I was hoping to cook up some sort of HID fixture with a 'tight' spot-light-like reflector to put most of the light into the tank, even with the light mounted 2 - 2.5 ft above it

I found a place online that sells a 250watt mh ballast kit for $46, which is the cheapest I've found anywhere for a mh ballast (core and coil design)

http://www.lightingcloseout.com/prod...2&CategoryID=3

Is this ballast suitable to run an Iwasaki(sp?) Super-Daylight 6500k bulb?

I've also noted the Iwasaki bulb varies A LOT in price, some sites have it for around $60-80, others want nearly $200 for the 250w with mogul base

also, is it true these bulbs only last a year??? or is that only for the radiation that corals need to grow ... I plan on just using it with freshwater plants/fish ... I'd hate to have to buy a new $80 bulb every year - ouchies!

other than DIY, is there anyway to get into Daylight* MH for under $200? Sure I can buy a 175watt mh flood light for $75, but it's only like 4100k, which looks awful under water (been there, done that)

what about taking that 4100k floodlight, and putting it behind a piece of blue-tinted glass ... not a heavy tint, just enough to soak up some of the red and green light?

thanks
glm

[fishfreek]

You need to match the ballast wattage with the bulb wattage.

The MH bulbs being to really lose spectrium after about 1 year. They will slowly dim down and lose specitrum after that time frame.

You really should replace your florecent bulbs every 6-9 months. So its not that big of a difference really.

Look at www.hellolights.com if you have not yet. I think what you want is a pendant reflector.

[justDIY]

so, "any" 250 watt mh ballast will run "any" 250 watt mh bulb?

what is all this jazz about m58, m59, m138, pulse start, probe start, cwr, cvr, etc?

http://www.hellolights.com/25methalretk.html
with the iswakai bulb would get me into MH for about $160

if the bulb is ruined after a year, is there much point in going electronic, which claims "up to" 25% longer bulb life?

http://www.hellolights.com/25methalbalk.html
would cost nearly $240 with bulb!

* The premade pendants they have there are nice, but nearly $300 for a single 250 watt - it's probably worth it, but still too much for me

----
I think it was GE's website or somewhere, but they recommended maintaining a high bulb temperature and a low ballast temperature, to maintain color, bulb life and ballast life ... does this sound right?

what is a "high" temperature for a bulb?

if I'm remote-mounting the ballast several feet from the bulb, and the bulb will be 18 to 30 inches above the tank, does it really need a fan (assuming a metal enclosure)?

thanks for taking the time on these questions
glm

[justDIY]

*bump*

[loganj]

OK, I am by no means an expert on MH...still learning. Here are a few things I've found out that might help you out some though. The Iwasaki bulbs will fire and run on a mercury vapor ballast. Advance makes one that'll work for $50 or a little less. Any MH ballast won't fire any bulb. There are some differences in the way they start...pulse, probe, ect... I don't remember the exact differences, but I think I can find the site where I read about all that...I'll post it if I can find it. AFAIK, the electronic ballasts will fire most any bulb. I think they're worth the extra money as you are supposed to get better bulb life and less power consumption with them. The Blueline ballasts will give you about the same output as a core/coil ballast with less power consumption. The Icecaps will give higher output than the core/coil with about the same power consumption. Aquatictech.com has the Icecaps on sale...click the "Internet Specials" link on their home page. The Bluelines are available from Champion Lighting. To concentrate the light, you'll want the bell shaped pendant. I'm sure you're familiar with the ones I talking about. I think that would be an easy DIY once you found some enclosures to use as pendants. Hope this helps some.

[loganj]

Check out this post...it might answer some questions you have.
http://www.aquariumadvice.com/viewto...824&highlight=

Ok, I hunted down the DIY for MH with MV.. and under $100 per setup...

http://aquarium.union.rpi.edu/articles/DIY_MH.html

[justDIY]

ok, so I need to find a inexpensive source for 250watt mercury vapor ballast and a mogul socket ... and then buy the bulb from online, and a few hours browsing shops looking for a reflector and presto, mh for under $100

great tip timbo, thanks a lot

[loganj]

I've had good luck using white painted aluminum for reflectors. I get it from a shop that sells supplies for race cars. I usually get a 4'x10' sheet. If you have access to a sheet metal break, it's really easy to turn out a nice looking reflector. If not, perhaps you could cut it and mark where you want the bends made. Then take it to a sheet metal shop and have them break it for you. Parabolic reflectors average $25-40 on the net...I pay $41 for a whole sheet of aluminum. I'm also wondering, if you wanted to go with a bell type pendant to concentrate the light better, is there some kind of aluminum or stainless container that you could cut down to use as a reflector.

[loganj]

Here's a few links that might make for interesting reading.
http://www.cyberreefguru.com/diy/mh/mh.html
http://www.geocities.com/Heartland/G...mhpendant.html
http://www.thekrib.com/Lights/reflectors.html
http://www.thekrib.com/Lights/