Incadescent bulbs!

[Caper]

In my little 10 gallon it has (2) 15 watt bulbs. I find when the 2 are on it puts the temp up quite a bit so I have turned one enough so that it doesn't come on.

Yesterday I bought a 25watt blue bulb. It has the same voltage, 120V, as the 15 watt bulbs. I just put it on and amazingly the cory's are out and about, yah ! Unless, of course I get too close

But, will this get as hot as the clear 15 watt bulb?

Should I only use one (at present just bought the one), or could I put 2 in?

Oh, the bulbs are Marina Augariu light bulbs.

Anyone

Caper

[Stella]

well, the blue part is just the glass right? That will not affect the heat.

The voltage is the same... I am not good with understanding that side of electricity.... but I suspect a higher watt bulb, which (if it was clear) would produce more light and more heat.

They probably make it a higher watt to get through the blue glass.

I don't know what corys are, what is it about the blue light that brought them out? Or is it a pseudo-moonlight thing?

[Caper]

Thanks Stella

Yes, the glass of the light is blue. So I was also wondering the same was the higher wattage to get through the blue glass?

but I suspect a higher watt bulb, which (if it was clear) would produce more light and more heat

Yes I would think that too, so in the scheme of things I wonder if the 25 watt blue is the same as the 15 watt clear???

They do come out from hiding more when it is on, unless I get to close to the tank then zoom hiding again...they are, as we would say when we were kids, real scardee cats! oh, no pun indended :lol:

Caper

[alanmin4304]

The 25 watt bulb uses 25 watts and the 15watt uses 15 but most of that energy is wasted and is emitted as heat. I am not sure how much , but only a fraction of the wattage will actually be light. The blue light looks blue because it is treated to block the other colours so it only emits blue light. It will therefore emit an even smaller amount of light than if it were not treated. I use red lights as a source of heat for baby turtles because the red is less disturbing than normal light at night yet still provides as much heat. I buy the bulbs from the $2 shop (two for $2) instead of about $50 from the pet shop and they produce enough heat for what I want.

[Caper]

The blue light looks blue because it is treated to block the other colours so it only emits blue light

But, alan, the glass of the bulb is actually blue colored, almost a dark blue.

Now obviously I know nothing about this stuff :-? , but would it take more watts for light to go through a darker shade of bulb as opposed to a clear one?

I use red lights as a source of heat for baby turtles because the red is less disturbing than normal light at night yet still provides as much heat

So, do you think this would be the case for my blue light...providing the same amount of heat?

Thanks,

Caper

[alanmin4304]

Most of the energy from a bulb is heat. It looks blue because the other colours are blocked out.

[Robert Smith]

The amount of heat you get depends on the efficiency of the bulb. This can vary quite a lot. For example, for 40W 4ft bulbs the amount of light can vary from as low as 1900 to as high as 3300 lumens. I've no idea as to the efficeincy of yours, but worst case is that you'd have a bulb that gives significantly less light and thus more heat. But just because the bulb has a blue filter, that doesn't mean it is less efficent than your previous bulb.

Without the details of efficiency from a paper specification (lumens per watt) try measuring the temperature with a thermometer under the hood!

[Caper]

It looks blue because the other colours are blocked out.

What do you mean by blocked out :oops:

The blue light looks blue because it is treated to block the other colours so it only emits blue light

Obviously I am missing something here...what is treated? Could this happen with clear glass, this treatment thing you're talking about so that only a specific color will emit as you say.

The actual color of the glass is dark blue without the bulb being turned on. Does that not make a difference?

Robert wrote:

but worst case is that you'd have a bulb that gives significantly less light and thus more heat

I think you're right I need to try to get the temp because that (as you say above in quote) is not what I want, I want LESS heat.

Thanks to you both for helping

Caper

[Stella]

Take a torch and some coloured cellophane or similar.

Shine the torch on the wall (preferably at night with the light out!)

It makes some light.

Shine the same torch through the coloured cellophane the same distance from the wall.

Much less light and it is the colour of the cellophane.

The same thing is happening with your lightbulb. The glass is blue so the light emitted is blue. Because the blue glass filters the light, less light gets through, so you need a brighter lightbulb (higher wattage) to emit a similar amount of light as a clear bulb.

Does that make sense?

A higher watt light makes more light and more heat. Chances are the differences in heat produced by a 25 watt light compared to a 15 watt light is minimal.

I also have issues with trying to keep my tank cool and lights are a problem. I keep mine propped up so there is a bit of airflow underneath. I have a fan on one tank which cools it by evaporation and also blows away some of the heat.

[Robert Smith]

The measurement technique is the best diagnosis. But if you've now got 50W of lights where you used to have 30W of light your tank is either a lot brighter or a lot hotter! You can answer the first question yourself. An extra 20W is quite a lot in terms of heat.

I don't know the bulb in question, but some blue/white bulbs actually generate blue/white light and the blue colour on the outside of the bulb is not what makes the light look blue, it is a layer of plastic that absorbs the UV, preventing UV damage to fittings etc.

If the light is obviously blue, then it's likely that the blue bulb is acting like Stella's cellophane. If the light is bright white then I think the blue is a UV filter.