MH ballast question

Jared J · 08-11-2008, 11:05 PM

Can I use a 150w bulb with a 250w fixture? I have been finding some decent prices on MH fixtures on Ebay but they are all 250W. I'd like to get a 150W halide fixture with a couple T5's for actinics. An electrician friend of mine said the 250w will still work, but it may overdrive the bulb reducing it's life. Any ideas?

Hop · 08-11-2008, 11:13 PM

Unfortunately I don't believe that they will fire the bulb.

Hop · 08-11-2008, 11:14 PM

And I would be careful shopping ebay for fixtures. Some of those deals are not that great and the fixtures on not UL listed, premature burnout and other problems. But there are also some good deals, you just have to shop around.

crvz · 08-12-2008, 08:51 AM

Quote:

Originally Posted by Hop

And I would be careful shopping ebay for fixtures. Some of those deals are not that great and the fixtures on not UL listed, premature burnout and other problems. But there are also some good deals, you just have to shop around.

Good eBay tip, I'd keep to name brands when shopping there. I've seen too many issues and even fires with cheap hardware that's not designed for the environment we stick them in (high humidity and enclosed spaces).

Don227 · 08-12-2008, 11:33 PM

If you get a good deal on a 250 watt ballast why not put you savings toward a 250 watt bulb? The 250 watt bulbs are not much more expensive. You will kill the 150 watt bulb earier so you will save money in the long run with longer life on the 250 watt bulb. These bulbs are too expensive to be tossing them out more often.

Jared J · 08-13-2008, 01:27 AM

Well, reason I was asking was because these lights are going over a 30G reef tank and I was trying to decide between a fixture with 1 150w MH and 2 65w PC actinics or the other ficture that has 1 150w MH and 2 24w T5 actinics. One gives me 9w/gal and the other gives me 6.5w/gal. The thing was that I only seem to find the 250w fixtures at a decent price but 250w is too much light for this tank I believe.

Other thing I was wondering was does anyone use light diffuser grates over their tanks and does it block out any of the light? I was thinking of using it as a cover instead of a glass top to keep my cat out of the tank.

crvz · 08-13-2008, 08:55 AM

Ah, there's the watts per gallon measure again. Useless, I wouldnt ever use it to justify a lighting purchase. If those T5 bulbs have individual reflectors, I assure you they are putting more usable light into the tank and would be the better solution. And they use less power, reducing your electricity bill.

The light diffuser will cut out some light, but so does the glass top, so it's probably a wash. The glass top also traps heat, though, so I'd be more inclined to use the light diffuser (well, truth be told, I'd be more inclined to drop the cat off on a deserted island, but that's mostly because I hate cats!).

Hop · 08-13-2008, 01:34 PM

Yeah the WPG rule isn't an accurate measurement of usable light. I only have 4.1 wpg and can grow SPS at the bottom of a 24" tank... And I could do that without the supplemental lighting for color which drops me to 3.026wpg

It's about par, intensity over the span of the light fixture and usable wavelengths. What does that mean? It means it gave me a huge headache!

Jared J · 08-13-2008, 09:51 PM

Quote:

Ah, there's the watts per gallon measure again. Useless, I wouldnt ever use it to justify a lighting purchase.

Haha, then I must apologize. It's been a few years since we've had a reef tank and we are getting refreshed on what's going on in the hobby these days. I had a 75g in my apartment but was forced to get rid of it because of the property management. First they cited no pets and when I argued that fish are not pets but a hobby, they said it was the water issue since they did not allow waterbeds either.

We own a house now so the itch is getting the best of me. The T5's are new to me, everything used to be power compacts.

jenglish · 08-13-2008, 10:08 PM

I hear you on the T5s, I left the reef aquariums alone for like five years and came back ready to set up another PC aquarium to find everyone telling me to buy these strange t5s I had never heard of! ANd yes, back then watts per gallon was considered a rough rule of thumb but it is no longer really even a valid estimate.

Loverotties · 08-14-2008, 11:22 AM

250 would be ok,just hang it a little higher!

Jared J · 08-14-2008, 07:37 PM

WEll, I found a fixture that has 1 150w 10K metal halide and 2 24w T5 "super actinics", but no lunar bulbs for $200 new in box and it's made by Sun Lighting Co. and is UL listed and has a 2 year warranty. Anyone ever heard of Sun Lighting?