Light question

[Shnabbles]

I was gonna order new MH bulbs for my tank. How can i tell the color from 10,000k 15,000k and 20,000k.. I cant remember what the fixture came with but i wanted to go with a more white and less blue light.

[logans_daddy]

all of these have a tiny bit of blue but 10000k is the most white while 20000k is the most blue. if you have some other actinic lighting, 10000k is your best bet or maybe even 6500k. if your not going to have any actinic then you want to go with a higher temperature.

if you want WHITE try the 6500k bulbs. thats what i have and i love them.

[MadTownMax]

It might say on the bulb - some manufacturers print the type on the side.....

- but FWIW, with two 96W actinic PC's, a 10K bulb is probably what you're looking for - 6500K are nice as they have the most available PAR (faster growth) - but to the human eye, they appear dim compared to 10K's - even though more photons in the correct radiation bands are reaching the corals - personal preference at that point as to if you want a "brighter" tank or a "dimmer" tank ;)

[Shnabbles]

Ill go with the brighter tank and the 10,000Ks thanks Nick.

By the way Nick that Ricordia i picked up from you a view months back is getting huge and has grown another mouth.. Its still on that little piece of rubble rock im hopping it splits and spreads onto another rock and i dont have to cut it..

The coloring on it is really nice its green brown and has pink stripes.

Thanks again!

[MadTownMax]

Logan's daddy - what brand 6500k are you running? And what wattage?

I know for 250W that Iwasaki's still hold the crown for the absolute highest PAR bulbs (even higher than 250W double-ended) but their color is a greenish-yellow....

Shnabbles - if you look though advancedaquarist.com you can find tons of articles on lighting and specific bulbs - that is your best bet for finding a good one to suite your needs - Sanjay has done a lot of research - 10K bulbs from one manufacturer might look blue - while others will look more yellow - then factor in that your eyes will actually adjust to the light output and it will look different entirely again (after working on my tank w/ the VHO's for a while, I always wonder why it looks so green outside :lol: )

[logans_daddy]

they are currentUSA double ended 150w 6500K. they came with the fixture. as far as color....i dont see a hint of blue in them but i agree that it is vary hard to discern with the human eye. i know that it makes my GE T5 6500K daylight bulb look yellow by comparison.

this being my first MH fixture i can not compare it to the brightness of 10000K, but if you think the 6500K look dim by comparison then i cant even begin to imagine.

i dont think i would want anything brighter....ive spent months searching the internet for little, tiny sunglasses for my fish as is.....i defintely dont want to waste time looking for little, tiny bottles of suntan lotion as well :D

shawn:bum:

[Shnabbles]

how often should MH bulbs be replaced?

[MadTownMax]

some people do 6-months, others yearly - some manufacturers have better quality bulbs that are guranteed to last 18-months (geissman) while other manufacturers - their bulbs could last 8 months or 4 years - varies from bulb to bulb.

I'd like to get a PAR meter to check out how bright my bulbs are before deciding to change them.

[kaptken]

You know, if you remember seeing hidden reefs display tank and what that looked like you will have some sort of standard to judge by. it was daylight clear. they had a pretty simple setup. one long fixture with 3 x 6500K halides flanked by 2 VHO actinics. always looked great, and you sure cant beat the growth. they used to use hamilton halides and had switched to KLH? or something like that. before the fire. i think they used 250w lamps. of course, i think the other maze of water chemistry controls and dosing had something to do with the results also. it was a high tech system alright.