Parr Readings!!!

Lil BamBam

Lil BamBam

Premium member
I was measuring my LED fixture from Coral Compulsion and Cubbies was helping. We hanged it over my 75gal at 30" and parr readings were 160/200+ and at 24" was 230/270+ something from sand bed.. We did it fast!! Since we had to hold this up in the air and couldn’t hang it for better numbers. So sorry!!! These are just fast numbers and might not be accurate.... Well try to build something this week to get better numbers and post.

Now my frag tank at 22" is reaching at 650 easy from sand bed and breaking surface is about 800+, but only has 6" of water vs my 75gal has more..

Now this is the question :wacko:

When doing these readings does it count how much height under water or it really doesn't matter when doing these readings at certain heights and amount of height of water :hmmmm2:

TIA!!
 
Dre, I cannot answer your question but for Z&P 650 on the bottom is too much, if for SPS then it's a great number. You see my frag tank I put all SPS on the top of the rock and move all Z&P on the sand bed. Some of the Z&P are not happy with high PAR.
 
maidia said:
Dre, I cannot answer your question but for Z&P 650 on the bottom is too much, if for SPS then it's a great number. You see my frag tank I put all SPS on the top of the rock and move all Z&P on the sand bed. Some of the Z&P are not happy with high PAR.
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Mai, this fixture is dimmable and was just testing at 100% before I dialed it down to my liking at 150-200
 
if its an apogee sensor it will also read about 25-30% low on leds... something to keep in mind, start low With leds, par of 50-75 on the sanbed is about right if u want softies down there.
 
Lil BamBam said:
I was measuring my LED fixture from Coral Compulsion and Cubbies was helping. We hanged it over my 75gal at 30" and parr readings were 160/200+ and at 24" was 230/270+ something from sand bed.. We did it fast!! Since we had to hold this up in the air and couldn’t hang it for better numbers. So sorry!!! These are just fast numbers and might not be accurate.... Well try to build something this week to get better numbers and post.

Now my frag tank at 22" is reaching at 650 easy from sand bed and breaking surface is about 800+, but only has 6" of water vs my 75gal has more..

Now this is the question :wacko:

When doing these readings does it count how much height under water or it really doesn't matter when doing these readings at certain heights and amount of height of water :hmmmm2:

TIA!!
Click to expand...

When you say you hung it at 30", is that 30" from the surface, or 30" from the sandbed? On a 75g, you want that fixture only about 8-10" from the surface, so about 26-28" from the sandbed. And when measuring par values, you want to measure at the surface, approx. halfway between surface and sandbed, and then at the sandbed.

The reason par values vary at different depths of water is due to the amount of light that can penetrate through the water. The right side of a spectral chart (red, yellow, and orange) do not penetrate water very deep, only about 12" or so. The left side of the chart (green, blue, and purple), penetrate much deeper. This is why everything appears blue in the ocean, because that is the color of light that penetrates deepest.

Now, this is also why there is some controversy regarding par readings. Because par meters read visible light spectrum much better (ie: red, yellow, orange, green). So the more of that color emitted by the light, the higher the par values. However, par meters have difficulty measuring blues and puples, which is actually what most of our corals need the most. And this is where the concept of PUR values comes into play. PUR factors in USABLE light, not just intensity. However, there is not an easy way to measure PUR, so people tend to resort to PAR readings to analyze lights.

Just thought I would share some of the science behind those numbers :)
 
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