Apogee MQ-200 question

rfgonzo

New member
I just received my new par meter and trying to figure out if you guys with meters turn your powerheads off when measuring or leave them on? If I leave my powerheads on the reading jumps all over the place from like 200 to 400, but if I turn them off, I get a solid reading. The only thing is the tank obviously runs with powerheads on, so how do you get a true reading?
 

slief

RC Sponsor
Premium Member
Off will get you the most accurate reading. The surface agitation can make it impossible to get an accurate reading.
 

rfgonzo

New member
But them how do you understand what you're reading would be with agitation? Is there some type of multiplier? Because with pumps on, I know that's not the par coral is receiving.
 

acabgd

New member
Well, everyone (mostly) measures with powerheads off, so if you want to compare your results to others then do the same.
 

slief

RC Sponsor
Premium Member
But them how do you understand what you're reading would be with agitation? Is there some type of multiplier? Because with pumps on, I know that's not the par coral is receiving.

The surface agitation causes fluctuations. The max you will see with the surface agitation will be about what you measure without it.
 

trueblackpercula

New member
Thanks my good freind bill lent me his. So I will be taking reading from my mitras lx6100hv for each set point. I keep most acroporas what's a good par to get from blues and seeing my project changes throughout the day at its peek when all LEDs are on what should it be where I keep acros? 400 to 600 the norm or should it be lower?
 

slief

RC Sponsor
Premium Member
Glad to help. I'm not an expert on SPS but if you have 400+ par in the water several inches below the surface, you should be fine. Just don't bump the intensity to fast. Make sure you acclimate the corals slowly to the light. Especially if you are making adjustments. FWIW, Par meters don't read the bluer light above 400nm as well as they do whiter light below 400nm. As you get more blue, the meterrs accuracy declines. There is compensation built into the par meter for blue light but the bottom line is that good led's are more powerful than the par meter will lead you to believe. Also, most of our corals get the majority of the photo synthetic radiation from 420nm+. The bluer the light, the less visible the intensity is to the human eye and the par meter but that doesn't mean the corals are using that and in fact, you can easily burn the corals if you aren't careful. Thus the need increase intensity slowly. Just because it isn't bright to your eye or even the par meter doesn't mean there isn't a lot of light for the corals.
 

trueblackpercula

New member
Thanks for the advice and information. I am running at 75% and will do some test to see how it goes.
Thanks for clarifying everything now I can start testing soon.
 
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