# Electrical tape to reduce intensity



## MCHRKiller (Jul 25, 2008)

Years ago when I owned piranha, I would wrap the bulbs on my fixture in electrical tape to reduce the lighting so they would feel more secure. Since I am dropping all of my tanks down to low light I also need to cut the intensity of my lighting. Would the same principle work so I dont have to purchase new fixtures? I use mainly Current T5HOs and this is proving to be too much light without CO2 and daily ferts for most of my tanks. So I thought about this old method to essentially make the bulb look like a candy cane in order to reduce the intensity. Would this work?


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## Gplus (Apr 2, 2012)

That's an interesting idea. Not sure if the bulbs would get to hot for the tape. You could try some high temp black paint. Tape off a small strip for light to shine through and paint over the rest of the bulb. Let it dry, peel tape, done!


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## Mariostg (Sep 6, 2014)

I am a little concerned about the heat generation.
Other options:
-Reduce the efficiency of the reflector. 
-Raise the lamps.
-Use egg crate beteen lamp and water surface. I heard people use fiberglass but not sure how they do that.

I suppose you cannot reduce the number of bulbs if you have more than one per tank?


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## MCHRKiller (Jul 25, 2008)

That was my concern since these bulbs are producing much more light/heat than my old T12 single tube strips back in the dinosaur days of fish keeping in using the tape. Candy cane wrapping a tube back in the day was standard practice for many skittish piranha species and worked very well. 

How could I reduce the efficiency of the reflector? Also the currents do not have a built in hanging kit, I am uncomfortable in my ability to drill them and hang them. I am by no means a handy person. 

Would the high temp paint stick to the bulbs? I had considered that as well but was afraid it wouldn't stick to glass.


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## Mariostg (Sep 6, 2014)

To reduce the efficiency of the reflector, you could paint them (may have a problem to strip the pain after) or slide in some darker material. I don't know how the fixture is built.

Without drilling, you could probably adapt the holding supports to fit small chains. Can you post pictures?


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## Hoppy (Dec 24, 2005)

One of the easy ways to cut the intensity is to put a layer of ordinary fiberglass window screen between the light and the tank. It can be attached to the top of the tank, attached to the bottom of the light, or made into a cover for the tank. Each layer of the gray color screen cuts the light intensity by 40%.


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## Mariostg (Sep 6, 2014)

Hoppy said:


> One of the easy ways to cut the intensity is to put a layer of ordinary fiberglass window screen between the light and the tank. It can be attached to the top of the tank, attached to the bottom of the light, or made into a cover for the tank. Each layer of the gray color screen cuts the light intensity by 40%.


Ok, that's gonna sound stupid, but I have seen that fiberglass idea too often, so I need to ask. So that ordinary fiberglass window screen is just that screen mesh that prevent flies from getting inside the house right. If so, does that really dim the light enough? Just a little surprised


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## Raymond S. (Dec 29, 2012)

Does the tank have a cover(glass) ? You just lay a piece of the FG screen on top of the cover. That cuts the light by 30-40%. That egg crate thing does work, but as you get further away from the bulb to each side the light is reduced drasticly.
Most T5HO fixtures can be used/w one bulb only.
In my 10g tank I got tired of the old strip light T8 fixtures and bought an Odyssea two bulb T5HO on sale. Grew lots and lots of Cladophora. Hoppy's chart said I had 100 PAR.
Removed one bulb and never have cleaned the glass of GSA since then.
If you have a tank that is 20" tall you may not have enough left after you remove one bulb. What size tank and how many bulbs is there ?


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## klibs (May 1, 2014)

I put tape on my planted + LED fixtures to block out some light and they do fine.

Given you are talking about T5HO fixtures that generate quite a bit of heat you may not want to go this route.

I agree with others that you should just fit a piece of window screen to the top of your tank. They block out quite a bit of light


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## CannaBrain (Oct 3, 2008)

You could also wrap or affix cheese cloth to the bottom of the fixture, don't want it hanging to where it would be in water. Heck cheese cloth breathes, maybe you could wrap that around the bulbs themselves.


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## MCHRKiller (Jul 25, 2008)

I may try to put electrical tape on the splash guard to block some of the light. My tank is acrylic and doesn't have a top. Any thoughts on that working?


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## scotty b (Oct 23, 2012)

you could pick up some high temp paint from a auto shop and paint over all but a small strip of the bulbs


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## Argus (May 22, 2013)

Mariostg said:


> Ok, that's gonna sound stupid, but I have seen that fiberglass idea too often, so I need to ask. So that ordinary fiberglass window screen is just that screen mesh that prevent flies from getting inside the house right. If so, does that really dim the light enough? Just a little surprised


Yes, just ordinary window screen that is not metal. If one layer does not dim the light enough, add a second layer. The second layer should be rotated slightly so the two screen patterns can't line up. 

If you want to spend a lot of $$ you can get a large photographic neutral density sheet designed for studio lights.


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## Hoppy (Dec 24, 2005)

Mariostg said:


> Ok, that's gonna sound stupid, but I have seen that fiberglass idea too often, so I need to ask. So that ordinary fiberglass window screen is just that screen mesh that prevent flies from getting inside the house right. If so, does that really dim the light enough? Just a little surprised


Yes, it is ordinary window screen. I got it at Home Depot, labeled "Insect Screen" There is more than one color, but I tested just the gray color. One layer leaves you with 60% intensity, 2 layers leave you with 36% intensity, 3 layers leave you with 22% intensity, etc. Human eyes make very poor light meters, so a 60% intensity looks almost exactly like a 100% intensity.


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## MCHRKiller (Jul 25, 2008)

I had another thought, would auto car window tint on the fixture's splash guard also reduce the intensity? I plan to put electrical tape on the splash guard for now but I was thinking this may be a more permanent solution and it should still be able to slide in and out of the fixture for bulb changes with the window tint.


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