Emerald525 Posted March 14, 2011 Share Posted March 14, 2011 So being the impatient sort that I am. Instead of going on the waitlist we borrowed a par meter. Here are the readings we got on the first try. Bulbs are 2 months old and it is an 8 x 54 ATI PM setup. Light fixture is 8 inches from the top. Quote Link to comment Share on other sites More sharing options...
Emerald525 Posted March 14, 2011 Author Share Posted March 14, 2011 Those are really good reading . I didn't think you would get that high of par in mid tank (400) with T-5's. There is a thread on RC which he measured even higher par. Oh the dimensions of the tank are 48L x24H x 24W. The lights are 8 inches from the top because we didn't want to fry the hell out of everything that was used to our other tank. Bulb combo is 2:ATI purple pluss 1:ATI sunlight 5:ATI blue plus Quote Link to comment Share on other sites More sharing options...
Emerald525 Posted March 14, 2011 Author Share Posted March 14, 2011 Be sure to test several areas and use an average rather than trying to use the same spot when lowering the light. You need to do this to get a more accurate measurement because the direction of the light changes as the distance changes which can change the reading in a "Non-proportional" manner when you use a single location. I would want at least 5 readings in various places at each depth (10 would be better). I'll withhold my suspicions regarding myth vs. reality until after more accurate data is available. We did do several measurements and just having a slight angle to the meter made quite a difference. We also did test initially with the water splatter not cleaned off and then cleaned the lights and there was no significant difference in Par measurement. Quote Link to comment Share on other sites More sharing options...
grassi Posted March 14, 2011 Share Posted March 14, 2011 It mostly depends on how the reflectors were built. For instance, some Coralvue MH reflectors works better at 2 ft high (or something like that) compared to the traditional 12 inches. They were built for that (lower the heat and diffuse more), so if you lower the fixture you lose par. The powermodule was built to work at about 6-8 inches, and at that level you should get the best par that the fixture can produce in a standard tank. But it is not a spot source of light, so it is possible that it can produce more par when lower. Many people run them at 1-2 inches from the water surface. Par transmission is also influenced by the heat exchange area between the light source and the water, for the presence of evaporation vapors Quote Link to comment Share on other sites More sharing options...
LC Scott Posted March 15, 2011 Share Posted March 15, 2011 Ok some more numbers, this one is on the 40b. The lights are 2.5 inch's away from the water surface, 18 from the sand bed. top 600 middle 400 sandbed This one varys to much for an average. 40 to 190. depending on the amount of shade. All numbers are an average. also I seem to have alot of micro bubbles. Quote Link to comment Share on other sites More sharing options...
Emerald525 Posted March 16, 2011 Author Share Posted March 16, 2011 8 inches vs 4 inches So interestingly when we lowered the lights the PAR actually decreased all the lights were on PAR readings 8 inches from the top PAR readings 4 inches from the top Quote Link to comment Share on other sites More sharing options...
kriz2fer Posted July 1, 2012 Share Posted July 1, 2012 So what did you think was the best height for par? Quote Link to comment Share on other sites More sharing options...
Emerald525 Posted July 1, 2012 Author Share Posted July 1, 2012 So what did you think was the best height for par? 8 inches from the top which I believe was the recommendation. Sent from my BlackBerry 9630 using Tapatalk Quote Link to comment Share on other sites More sharing options...
Emerald525 Posted July 18, 2012 Author Share Posted July 18, 2012 Borrowed the par meter a couple of weeks ago thanks Smann. Here's some updated measurements: The numbers are reversed the lower numbers on the right are with the cover Quote Link to comment Share on other sites More sharing options...
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