After reviewing the lighting threads here, it appears I may have overdone my lights a little

I have a coralight aqualight 4x65 CF 260W 6700K, on my 72 G tank.

3 questions:

1. I simply have the aqualight right on top of the glass top. Is the a problem, would it be better to elevate the light above the tank?

2. Can I get away with varying the lighting and still get the red color from my plants? For example 6 hours at 2x65 and 6 hours at 4x65. Right now I am running 4x65 for 12 hours. Running pressurized CO2, fert regularly no algae probems.

3. I have read and been told that light penetration is a problem for flourescents, my tank is about 24" tall. Based on what I have been reading here I should be ok with my lighting setup correct?

Thanks

Fred

Hi Fred,

1. Raising the fixture will help reduce the amount of light the tanks receive. Having the ability to easily adjust this will help in other ways as well, ie access to the tank. I use normal closet shelving to accomplish this. I posted a thread on this DIY method a couple of weeks ago.

2. Many folks use 2 bulbs for the majority of the day and then all 4 for the 'noon' affect. I think you will still get good growth with this approach.

3. I have used Verilux 30w normal flourescent bulbs on my 24" deep tank and they worked well. Keep in mind that the higher light requirement plants will not do as well. You may have to adjust your expectations and the types of plants you keep.

Suggestion: You don't have to run all 4 bulbs at once. You can mix/match as appropriate.


Hope this helps.

Gerry

I would like to that with the closet shelving as that is practical. However the tank is in the family room and that might offend my wifes sense of decor . Fortunately the coralifes have mounting brackets so I will just use those

I wish I could use 3 of the 4 as I basically go from 3.6 wpg 1.8. High light to low light. The fixture is a CF with two switches each controls 2 lights. I have Rotala
Macranda that I am trying to grow and it needs a lot of light, so I'll probably be stuck with leaving the light on most of the time.

Thanks for the advice

Fred

Fred,

Why not two timers, one for each switch that controls two of the lamps?

Example

Timer 1 On: 10 am
Timer 2 On: 12 noon
Timer 2 Off: 4-6 pm based on need
Timer 2 Off: 9 pm

Total duration of light 1 is 9 hrs and combined is only 4-6 when you have all 4-5 wpg...

I do this with my 45 gallon that has two twin bulb floros and it works well.

You can still grow R. Macantha, just ensure it gets the most of the 'extra' light....

I hear you on the DIY closet kit and your wife's taste

Here is a pic of mine in the living room.

Good luck

The only light "penetration" issue involved with fluorescents is related to the reflectors. Light is light, whether it comes from a long tube or a small hot ball. It is the reflector that collects the light from the sides of the bulb that don't face the tank and redirects it into the tank. If it were possible to reduce the diameter of a fluorescent tube to one mm, you could use a linear parabolic reflector to generate a parallel beam of light that would uniformly cover the entire volume of the tank. That, of course isn't possible today.

Water absorbs light, especially light at the red end of the spectrum, but in a 2 foot deep tank that absorption is very small.

Now, if you need to persuade your significant other that you have to buy expensive MH fixtures to get adequate light to penetrate all the way to the substrate, just ignore what I said above.

Heheh, while that is a temptation, I think the reflectors on my fixture are good enough. I can probably do just fine with the lighting I have. I was just a little surprised on the recommendations for lighting here, where many others would lead you to believe you need 4wpg or more to grow everything. Thanks for the input

Fred