coralife mh question...

[chadman]

i accidentaly posted this thread in the fish photography forum...sorry....this is where i meant to put it...thanks...
two questions:
1. i am running two 150w mh 14 or 15k's....i purchased them about a week or two ago...is there any reason why one of them would be more blue than the other? the one seems to be throwing a much bluer light than the other....
2. my lfs told me today that the reccomend running 20k's rather than the 15k that comes with the fixture...any suggestions?

 

[stanlalee]

give them at least 100hrs or more to burn into their true coloration. I wouldn't listen to your LPS about 20k. Particularly at 150 watts most 20K bulbs are pretty sorry for good coral growth and personally most for me most are too blue. Are you looking for bluer lighting? Does your fixture have flourescent bulbs as well?

 

[chadman]

no i just have two pendants...what you said about the 20's being too blue is also what i heard which is one of the reason i went with this pendant...i read in the past how the 14k mimics the sun the best so if i were to go with only the 14k then i wouldn't need to add any other lights....

 

[stanlalee]

well what mimics the sun best depends on the depth of water you are trying to simulate but generally speaking 6500-6700k best simulates the sun and has the best growth however is extremely yellow and unattractive. 10K is whiter while still offering decent growth. some brands of 10K bulbs still too yellow for many. Usually the solution (and best one) is to add actinic or blue flourescent supplemental lighting. However 12-15K bulbs are generally considered the ultimate compromise between looks and growth if you dont want to use supplemental flourescents. They usually have no yellow tint and anywhere from a slight to heavy blue tint. Offer adequate growth and great looks. Some brands are better than others and some bluer than others. The best 12-14k bulbs have PAR inline with typical 10k bulbs while others have worse than 20K bulbs. 20K are for those who like very blue tanks or have high wattage bulbs like 400watts where growth is not going to suffer like it would with a 150w 20K. You have to shop carefully with 12-14K bulbs though (and any kelvin for that matter), some are still too blue, some may not be blue enough for your liking. Some claim 14K Hamiltons and 12K reflux for example are just as blue as many 20K bulbs. Pretty much a personal preference. If your LPS is heavily coral driven they will be able to show you a few examples. If not find one that is and has several MH pendants over their coral tanks. they are bound to have different brand and K bulbs over different tanks.