18000 K......what does that mean???

[CareBear3030]

I've recently set up a tank and decided to put in a couple of live plants. I didnt realize how much there was to it...but now I really like the live plants....and so do the fish! I decided I need to go get some more light. I cant really afford to get a new light set up so I thought I would try to at least get something a little better than what I had. I just went out today and got a couple bulbs that say they are for freshwater fish and help promote plant growth. I am now reading here about lights and see this K word with a value. Well the value on the lights I just got is 18000K, but only 15 W a piece. Is this too much??? What exactly is the K???

 

[seranko]

CareBear, K means degrees Kelvin (K). White light can have different warmth. A bit more red-yellow-white light appears "warmer". A bit more blue appears "cool". This can be quantitatively assessed by the assigning of a color temperature, given in degrees Kelvin.

Check this website http://www.killi.net/lighting/

Hope this help

 

[CareBear3030]

I am still confused??? This light does make it look more blue in my tank. I have mostly blue and some pink rocks, and now my pink rocks look almost purple. So if that just means it will bring out different colors I guess I understand....LoL!!

Is it safe for my fish/plants??

 

[justDIY]

color temperature has no effect on the actual intensity of the light. high or low K or Kelvin, the light is the same brightness, all other things being equal (wattage, technology, etc). regardless of what your "eye" thinks, because it is biased based on preconcived conceptions of what is 'bright' and also biologically sensitive to some colors more than others.

color temperature in freshwater is almost 100% up to the owner of the tank to pick what looks decent. the fish could care less, and the plants, without going to extremes, will also grow with just about any light.

color temperature in saltwater is a different topic for a different forum

So if that just means it will bring out different colors I guess I understand....LoL!!

Is it safe for my fish/plants??

basiclly, yes, different K brings out different colors. as far as it being safe, without going to extremes, yes, it's safe.

using something like actinic bulbs over freshwater could have negative impact on the plants, due to the fact that it is pure blue/purple light, with no red or green, leaving very little light for them to grow with.

 

[madasafish]

It is safe for your fish and plants (Aqua Glo, right??). I've got one on my 10 gallon. But your individual bulbs won't do anything unless you have enough *wattage.*

I assume your tank is a 10 gallon, so it needs 30+ watts of light. I think Rex Grigg would advise closer to 40 W. I've got 30W on my 10, and my plants are growing well! I also have a fertilized substrate and a CO2 injection system. When you get into plants, you really have to go the distance... unless you have amazon swords, Java swords or anacharis (some other exceptions).