Originally posted by mujtba
1. it is 250W DE bulbs.. I dont see any hint of blue in it.. so I am assuming it is 10K?
>>> Maybe.. But it might be a 6700K or even a 5000K for all we know, Having a "baseline" to know where we're strating from and what brand will help tremendously in choosing a direction to go...
Should be written "on" the bulb itself ...<<<
2. so what K should I get that will be blue?
>> Higher than whatever it is you have for sure...BUT some bulbs in the same K can have different "looks" so knowing what brand you have will help as well...<<<
3. If i get a 14K MH bulb or higher K, will that do it? also, will I need my actinics with it then?
>>> That also depends on "what you had" ...."what you get"....and "what your looking for"....If it's too blue after you change you may want to switch them to 50/50s or even 10Ks to "whiten" the tank back up... or "you" may like the tone..or "you" may want even more blue...The "Blue Look" is really more for "your" benifit than the corals...<<<
4. Is this good:
20K 250watt HQI Metal Halide Bulb - EVC Tech
>>>There are better.. . but alot depends on what your looking for ..price, PAR or curb appeal...With a little "searching" on your part , you should be able to come up with some "color chart comparisons" of different MH bulbs to help you narrow down your choices in "color" and then compare brands vs. ballast to get the most PAR for the buck...<<<
5. Could you plz explain the difference to me between Ks?
"K" is a measure of color "tempreture" over a band of radiation wavelegnths...The PAR or photosyntheticly available radiation is what the corals are interested in...the resultant "visual" band width (or color) is what you seem to be interested in... While higher "K" bulbs will tend to be more blue, that is not always the case especially when comparing different brands and/or running them on different ballasts...<<<
could you guys please answer all questions?
>>>"Some" of the questions can only be answered by you...<<<