lighting question

TIO

TIO

AC Members
Oct 9, 2006
32
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0
Anchorage, AK
When we recently moved everything into a 95g wave tank, we also purchased a new light. The fixture came with two 21" 65 watt Actinic & two 21" 65 watt
10000°K bulbs. I've been reading about the actinic bulbs, and I'm getting mixed info. Are actinic bulbs alright with freshwater planted tanks? I know the actinic bulbs are used in marine environments to promote coral growth. Will they have any negative affect in a planted freshwater tank? Would it be wise to swap the two actinic bulbs for new 10000°K bulbs?

Thanks in advance!
 
Most people that grow plants (me included) use bulbs of 6500K. These are more yellow in color.

You can add bulbs of either more blue or red, ect to enhence fish color.
 
The actinic bulbs won't do as much for your plants as 6500K, 6700K or GE 9325Ks (can you even get these in a 65W square base?) will. Generally speaking, anything between 5000K and 10,000K rated bulbs will work for plants. If you want whiter light, look at CRI ratings. The closer to 100 you get, the more like sunlight the output will be.
 
Thanks for the responses... much appreciated.

So let me make sure I understand this correctly. I have four 65 watt bulbs... a total of 260 watts. Going by the "3 watts per gallon" rule, I'm a bit short(95 gallons x 3 watts=285 watts). Combined with the fact that two of those bulbs are actinic, and theoretically not doing much for the plants, I'm about 130 watts short of where I want to be in regards to wattage.

Right? Wrong? Is the "3 watts per gallon" rule generally accurate?

Thanks again!
 
in a 95 gallon tank, 3 watts per gallon would be fairly high light. If you switch the actinic lights to daylight you would need CO2, ferts, etc to stay ahead of the algae. What kind of plants are you planning? If you don't want to do CO2 and ferts you could probably keep the lighting you have and go with low demand plants.
 
We currently have a couple swords... one Amazon and one that was labeled "banana sword". My plan is to take some offshoots from the Amazon and plant them as well. My understanding is that they were moderate light plants, and they've done well so far. We are having quite the explosion of hard, speckled algae, though.
 
What UCF-Planted said. At the most I would throw in a 3rd (leaving one out or maybe keeping the actinic) bulb in with a good red spectrum to round out your light.

Squawkbert said:
If you want whiter light, look at CRI ratings. The closer to 100 you get, the more like sunlight the output will be.
Click to expand...

It is a bit of a misnomer to say that high CRI is whiter light. CRI is the Color Rendering Index and determines how rich the colors appear. A light could have a 98 CRI, but still be in the 3500K color range, so it would appear reddish/orange and it would enhance any plants that are reddish colored. Color temperature and CRI are independent of each other.

This link is a good read for lighting info and what the numbers mean (not plant related however):
http://www.lightsearch.com/resources/lightguides/colormetrics.html
 
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