And here's my Lighting Question

[BalaShark]

I have 3 x 250MW MH's on my tank. Is it a myth or the truth that the need to be replaced every 6 or so months? Dang, at $75 a piece, it seems a bit much twice a year. If you have to replace them is there a scientific reason other then the LFS saying so?

Another question, do I need 14000k's or what is the difference between 14000k and 20000k's? GE sells 250W 20000k's for around $18.

 

[BalaShark]

According the Marine Reef Aquarium Handbook By Robert Jay Goldstein, Michele Earle-Bridges, MH's should only be replaced when they start flikkering, see page 63.

 

[1979camaro]

Most people say every 9-12 months is good for MH bulbs. Basically, like any other bulbs, over time their spectrum shifts and they lose their effectiveness... It isn't just an LFS myth.

The difference between 14000k and 20000k bulbs is going to be the blueness of the bulb. 20000k will be more blue and you will probably see less growth than with 14000k, on the other hand the corals may look nicer under the bluer bulb. Kind of a personal preference thing really.

 

[quaddity]

I'm running cheap Chinese 20ks on my 90 and haven't seen any ill effects after switching from $70 Coralvues. They're probably made in the same factories anyways but Chinese ones are less then $20. The brand I have been using for the last 5 months now is Aquar Mckzo. They are so cheap and I like the color of both 20k and the 14ks. I have a stock of them now. For $10-$15 they are not bad at all. I have had one that was defective and burned out on me after a few weeks and the seller on Ebay replaced it for free. PAR wise they are on the lower end of the scale but suprisingly better then some of the expensive bulbs like Coralife. I can't remember the name of the guy that does all the PAR tests on bulbs but it was his site that I read of a review of them and decided to try them.

The color of the MH will shift long before it flickers I would think.

 

[Chris_A]

I can't remember the name of the guy that does all the PAR tests on bulbs but it was his site that I read of a review of them and decided to try them.

Sanjay Joshi and for anyone interested: Manhattan Reefs - Sanjay's Lighting Guide

The down side is it's fairly limited for some people... I don't have access to even a quarter of the lamps and ballasts he's tested... In most cases it's just depressing for me to find out most of the ones I *DO* have access to are so low in PPFD...

And I normally change mine once a year... give or take. If I miss it by a month or so I doubt there's any serious issue.

Chris