# Proper PAR?



## coralbandit (Jul 29, 2012)

So first I will say that being a "good" member here has it's benefits!Big thanks to jrman(Ben) for loaning me his Apogee Quantum flux PAR meter(sorry if I let the cat out of the bag Ben!).
I realise that every plant is different and has different requirements so the answer to this could be very broad,but generally speaking what is high PAR?
Is it measured at surface,middle,bottom of tank.I do realise the reading should relate to where the plant is,but I do really love stupid questions,so this is what I wonder?


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## jrman83 (Jul 9, 2010)

Hope you are having fun with the meter. 

The measure of high light generally refers to your PAR reading at the farthest point from your light or your substrate. I believe the agreed upon range considered high is 50-60PAR. It is also generally agreed that you really don't need any more than that to grow any plant you may want. If you have much more than that usually people will lift the light or if you have a controller, dim the light.

My dual BML light read 125-130PAR at my substrate so I back down to about 80%. Haven't played enough with my dimmer and meter to get me in a safe place.


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## coralbandit (Jul 29, 2012)

Thanks Ben.After work today I will work on installing a "track" to rest lights on at the top of tanl.I'm going to lower the lights even more and see what my readings are then.I'll post everything when I do.It has been a busy work week so far so I haven't had much time being home when lights are on.


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## coralbandit (Jul 29, 2012)

So it would seem a large difference with lights closer to water!With lights suspended 8-10 inches above water PAR was around 25 or less at the bottom of tank.It is now37-40.That may not seem like a large gain, but inches make a HUGE difference;Just 6" above the bottom of tank PAR is 70+,and 6" below the water surface it is 270+!With the sensor just sticking out of water PAR is a whopping 480!
So I could probly keep almost any plant except some of the high demand carpeting plants?
I will leave lights low to water for now and observe.I kept the "rack" I made for suspending lights in tank just incase I decide to raise some of them.
General info on tank and lights;180g aqueon with dual mega overflows,aprox 24 inches from lights to substrate.Lights;4 @ 4' [email protected]' [email protected]' all current true lumen PROS.2 of the 2footers and 2of the 4 footers are fusion(some blue with 12K white{1 blue for every 2 white}and the rest are 12K white.


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## dalfed (Apr 8, 2012)

A little food for thought Bandit... if you are using a high spectrum light bulb 25 is probably lots to grow any plant. If most of the light you are reading is in the easily used PUR ranges for aquarium plants (blues and reds) then a 25 PAR reading would be substantially easier for plants to grow then a 60 PAR reading of mostly yellow and green lighting. 
PAR is definitely a better measurement then WPG but still must be looked at for what it is.
I have a test for you to run since you have the new toy, if you would be so kind, could you wrap a tank with a blue towel and see what the difference in par reading is, then maybe a red..white...black lol etc. 
Just inquiring mind that thinks there may be better background colors for planted tanks that would aid in light refraction to increase distance good light good reach in a tank.


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## Gizmo (Dec 6, 2010)

I'm jealous, all I have is a lousy LUX meter....


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