glass tops between your tank and lights

[strangepod]

I have noticed that since my tank change over and waiting to finish up my canopy I have had some old glass tops on the tank. My evaperation on the tank has gone way down. I have heard that the glass will filter out good uv light, is this true? Will these tops be a problem when I get my MH up and running again in a few days (the bulbs will be a good 10-12 inches away from it).

John

 

[slayer]

glass will only filter out the bad uv as far as i know, thats why its recomended to use a glass cover over double ended bulbs. You will loose some par with a glass cover b/c of its lead content and yes your evaporation rate will go down, but the heat trapped inside your tank will go up, making the temp of your tank rise. it wont be much of a problem right now as we hit the colder weather but will become one when summer starts rolling around again.

 

[ichthyoid]

I have attached a link to an article that discusses UV and it's effect on photography, but it does a good overall job of explaining the issues. The practicle aspect is that most UV will become 'scattered' within a few meters of the surface in seawater. Scattering is a simple process with a very complex explaination, so i will leave it at that. The artcle below touches on it, and you can look it up if more interested.

I'm not sure what you are referring to when you said "the good UV", but if it's vitamin d synthesis you refer to, then yes it will reduce the wavelengths between 290-300 nM significantly. This is where vitamin d is synthesized. If it is flourescence you are looking for, the glass will not interfere with that. The graph below explains much.

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[ichthyoid]

Also-

I guess by 'good UV' you could be speaking of that which does not cause damage</em>?

In that case, regular glass will filter out damaging UV, but leave the rest.

 

[smoothie]

Clean it as often as you do your display glass if you do go with it. If not go with acroholic's mesh top
A glass lid will hold back on cooling/evaporation in the tank regardless