Window screen light filter

[redfishsc]

There are some times that lower PAR can appear "brighter" to our eyes than some "higher" PAR situations, but it's never comparing apples to apples and there are always intervening variables that make a mess of trying to predict it.

My 11g and 45g are both LED lit but using very different LED combos and driven at different drive currents.

The 11g has a PAR of about 30 on the sandbed and it appears quite bright to my eyes. Yet my 45g, which also has around 30 on the sandbed, looks pitifully dim.


I'm not entirely sure of why this is. If I crank the LEDs up on the 45g such that it looks bright to my eyes, I get algae hell.



I'm not sure how "green" registers on a PAR meter, but our eyes are way more sensitive to green light than plants are, so a green light that's ludicrously bright to us may not be all that useful to a plant. You'd think that this means "lower PAR" on lights high in the green area, but this is just a guess.

[wespastor]

One benefit that I use the window screen for is to shade part of my tank from the High light that some of my plant like / need and give my low light fish a place to hide from it.

Best wishes,
Wes

[barbarossa4122]

I am so pleased I bought the window screen the other day, thanks to Hoppy. And, according to him I reduced my lights about 30 to 40%. My 55g is looking a little dimer now but, who cares. Btw, I use 2 54w Geisseman on this tank, about 10" from top of tank.

[sayurasem]

Hi guys, I found this thread so I just continue here...

Something is odd about the spectrum of my Finnex 36" LED light using the window screen. And I just notice I bought the grey instead of black screen. Do you guys think its because I'm using grey screen the light spectrum went out of wack like this?



Two screen on


Two screen off




The same thing happened when I only use 1 screen.

[Hoppy]

It looks like you are getting a diffraction effect that makes those bars of light show up. I haven't tried the screen with a LED light, so it may not work the same way. All I know is how it works with fluorescent lights. But, when you start shining light from near point sources through any form of "grating" you can get unexpected results (unexpected only to a non-physicist).

[somewhatshocked]

I've been using black screening with Finnex fixtures and it works well. Takes 2-3 layers to accomplish what a single layer can do with a regular bulb-type fixture, though.

[sayurasem]

Originally Posted by somewhatshocked

I've been using black screening with Finnex fixtures and it works well. Takes 2-3 layers to accomplish what a single layer can do with a regular bulb-type fixture, though.

Do you get the light bars like I did?

[somewhatshocked]

Nope, no bars.

What does your fixture look like when you place it over your tank while using the screening? Still get the bars?

[beedee]

I have an AquaticLife 36" T5HO with one 6500k bulb and one Roseate bulb, I'm using 3 layers of the gray screen over my 12g Long. I'm only using the stock legs that came with the light to elevate it above the tank, so at it's highest point, the light is about 14" above the substrate, and at the lowest, about 8".

The tank has only been filled for one week, but so far so good. I'm debating on removing one layer of the screen. My photoperiod is 6.5 hours right now.

Thoughts?