MH Light Question

Soulofamind · 08-23-2006, 04:09 PM

Hello again TRT! Hmm... I've noticed I've been posting alot for the past couple weeks. Haha!

Anyways... I currently own a 175w 15k MH Odyssea lighting system. Now I've had it for over a year. I've read from books and sources that its best to change them every 6months to a year. But is there a way you can physically tell its time for a change? My LFS (who sold me the MH lights) told me that if the spectrum is starting to look a little yellow... its time for a change. Yet I notice no yellow hue from the blub. It's still starky white. I'm very confused as to when to change the bulbs. Hehe. thanks everyone!

Wiskey · 08-23-2006, 04:57 PM

Sort of taking Par measurements there is no real way to tell if the bulb needs replacing, just go by the time it has been running. Bulbs drop intensity, and/or shift spectrum over time, but with-out expensive tools there is no real way to tell how much unfortunately.

Whiskey

DevilBoy · 08-23-2006, 07:09 PM

here ya go look into getting something like this. it will let you know the light intensity anywhere in your aquarium from the surface of the water, all the way down to the sandbed, and even under overhangs.

http://www.premiumaquatics.com/Merch...Code=Milwaukee

SteveNichols · 08-23-2006, 07:23 PM

That just gives fooot-candles. It doesn't tell you anything about the quality of light. You can find some cheap spectrum meters to let you know when the light has shifted, but the chep ones don't really give an accurate idea of the true spectral quality of the light. I just used it to see the shift. I used to get one from the physics department and found out I needed to change the lamps at avout 8-9 months. They were 6500K Iwasakis. I didn't check any other lamps. Sanjay Joshi may have some detailed info on his site. http://www.reeflightinginfo.arvixe.com/

Wiskey · 08-23-2006, 08:00 PM

I have one of those LUX meters, they read visible light, not necessarily PAR. For example if your bulb put out all green spectrum, it would still get a high reading on that meter, but the Par would actually be very low.

Those meter's are a good baseline, and as bulbs age I do see a dramatically lower reading (especially PC bulbs) but it is no substitute for a good Apogee submersible probe par meter.

Whiskey