Intentionally Uneven Lighting?

[Rokuzachi]

I feel like this might be a silly question, and Google isn't helping me find an answer.

Have any of you ever intentionally lit a planted tank in a very uneven manner? For example, a MH pendant down at one end, and nothing down at the other on a 36-48" tank. I've been thinking about this all day.

I want to have very high light in my new 120g, but I have a couple of old favorite fish that are very jumpy under bright light when people are around. Most of my tank's shelter right now was built just for them, and half the tank has the surface cluttered with floating plants for the same reason (but my lighting is the full length of the tank). They're pretty content in that 1/3 of the real estate.

So I was thinking of putting strong light at one end, or just in the middle, keeping most of the plants there (but not all) to see how it worked out. Anyone tried this? I feel like I only see pretty much full/symmetrical lighting wherever I look.

 

[greenwater]

Yea........that would look good with the lighing and center piece off to the side. Mmmm, I have a five foot tank and now you have me thinking of how easy it would be to grow high, medium and low light plants.

Good luck

 

[aqua_chem]

It would probably look ridiculous, but it would be functional.

 

[greenwater]

It would probably look ridiculous, but it would be functional.

No, he has a great idea.
I'm already planing on replacing my four foot T5HO's with three LED units(low, med & high) spaced inside my hood. The only drawback is pulling up some of my plants to relocate them. They're doing so good the way they are.

 

[Rokuzachi]

Oh my, I just noticed my horrible typo in the title.

With my 120 I think I want to try a 250w MH in the center or at one end. Probably one end, so that it can be heavily planted there and taper off towards the dark end, which will be mostly open water and a few rocks/driftwood.

 

[mfdrookie516]

Well... does the sun shine in the lakes, rivers, streams, etc exactly the same in every spot? Nope... at least one person has done something very similar to this.

 

[CorallineAlgae]

I did just that a few years back over my 30L reef. I had a 150 watt HQI MH offset to the right side angled to point down toward the left. It gave the tank a very striking effect. It looked a lot like diving in the ocean either during the morning or late in the evening. I kept it that way for about 6 months and then centered it.

The idea was my high light corals were all under the MH light and the rest were on the left. I still had 2 36" VHOs over the tank so nothing was actually dark. If the tank didn't have a full hood I never would've tried it. I'd love to do it again with a planted tank.

 

[Link119]

For me, i would rather put some sort of driftwood that blocks out some of the light, so the whole idea of having different amounts of light in different areas is more natural, but thats just me...

 

[aqua_chem]

I had a tank with a 15w bulb on one side and a 13w bulb on the other and it drove me crazy. Too asymmetrical for my tastes.

 

[Rivercats]

I have a 220g tank with 3x150W HID MH light and 4x39W T5HO lights. In my big tank I run the T5HO lights 9am to 9pm then the MH's come on from 2pm to 8pm. The T5's provide a very soft viewing light that the tetra's love and gives a very pleasant morning-evening look to the tank. Since the big tank has two cross support braces the three MH's sit inbetween each section and I get a more concentrated high light blending dimmer/softer the further out it gets. So the overall effect is natural high and low light areas that are very appealing to look at. It also gives both plants and fish different light area to use. I've got high light and low light plants and it works great. Then by adding driftwood it really gives a stunning effect. The MH's will give the rippling shadow effect if you have surface movement, which mimic's what natural sunlight does in moving water. My tank is 30 inches deep and 150W MH's are way bright enough. I could use 250's but to me that would have been too bright to enjoy viewing.

 

[Mrc8858]

Didn't even think about it til I showed someone this pic but a vortech distributor near me that I bought some coral skeletons from did this in his 500 gallon in wall reef

 

[Rivercats]

I get the idea but I think it would drive me nuts in a short time. Plus I suppose since I have a freshwater planted I want to have a natural look with the lighting.

 

[mohican]

I saw this kind of lighting in a aquarium book I have. It looked so cool and natural with beams of lights in certain areas. Go for it.

 

[aqua_chem]

What might be cool is a non-perpendicular incidence of light. So rather than hitting the tank at 90 degrees, it comes it at 30-60 degrees.

 

[CorallineAlgae]

What might be cool is a non-perpendicular incidence of light. So rather than hitting the tank at 90 degrees, it comes it at 30-60 degrees.

That's exactly how I had my MH setup. It was on the right side of the tank angled left to shine towards the center. This was how I got a "morning light" effect. On it's own it looked very convincing, and with 2 VHOs it gave a more balanced look to my reef.

 

[Rokuzachi]

Hmm, good ideas...

I'm not good at the math of lighting (figuring out falloff and all of that), so what kind of light do we think a 150 or 250w MH would provide to the far end of the tank if it were placed above the last 12" of the tank, 8-12" above the surface, and angled towards the far end instead of pointing down?

 

[CorallineAlgae]

If it's a 120 gallon and you want "very high light" (from your first post) then the 250 watt would be the way to go.

EDIT: Sorry, I was in reef mode. 150w would easily be adequate for plants. When I did this it was for a reef so... still would recommend a couple of T5s if you want plants everywhere.

 

[Rivercats]

From my understanding if you go with very high light you will need CO2 to get proper growth of plants, not algae. I have high light and have to use a higher amount of glutaraldehyde which I had to increase levels slowly until I found the proper carbon to light in my tank. I also had to drop my halides down to 6 hours a day operating time. With doing these two things my algae is very low. I like some simply because my Whiptail Cats prefer algae and in the couple months I've hadthem they refuse to eat any veggies or algae tablets. You will also need to do a regular fertilizer dosing regiment as plants under higher lighting need more nutrients due to faster growth. I understand with lighting that way that only some plants would recieve high light but it is something you need to consider.

 

[Rokuzachi]

So a 250 would probably be overkill, yea? I'm not too familiar with lighting planted tanks above 55-75g. As long as I can get full, vibrant plants down at the substrate level in the area immediately under the light I'll be very happy. I've owned taller tanks in the past and had trouble with very thin/stringy plant growth at the bottom (which helped to teach me that the WPG rule is often flawed, nearly the same amount of wpg over two tanks, but one 18" deep and one 24" and totally different results in the lower levels of the tank). If a 150w can get me what I'm after though, that's what I'll do. I've seen some killer deals on 150's lately.

 

[Mrc8858]

So a 250 would probably be overkill, yea? I'm not too familiar with lighting planted tanks above 55-75g. As long as I can get full, vibrant plants down at the substrate level in the area immediately under the light I'll be very happy. I've owned taller tanks in the past and had trouble with very thin/stringy plant growth at the bottom (which helped to teach me that the WPG rule is often flawed, nearly the same amount of wpg over two tanks, but one 18" deep and one 24" and totally different results in the lower levels of the tank). If a 150w can get me what I'm after though, that's what I'll do. I've seen some killer deals on 150's lately.

Ya MH are gonna keep dropping in price plus more and more used ones will come up for sale with how quickly leds are taking over