StirCrazy
04-01-2004, 03:03 AM
well after a while I final got the initial PAR testing set done.
this test was conducted using the identical set up and the only thing that was changed was the bulb its self, and then the meter was positioned to the optimal position under the bulb but remained the exact same distance under the bulbs.
the set up for this test was a sensor mounted to an acrylic frame in my tank. the top of the sensor was 4" under the water and the distance from the bottom of the bulb to the water surface was 7". this made a total distance of 11" from bulb bottom to sensor top. also it should be mentioned that the ballast is an Advance M80 HQI ballast.
http://members.shaw.ca/steve-sherri/testholder.jpg
anyways back to the data. I tested a 2 year old AB (as a reference. wish I had a new one but I am going to order some in the fall) and the sun aquatics 10K, 14K, and 20K (I tested two of each bulb and took the average value as they were all very close)
OK
10K 250 watt AB (2 years old) 767.9 PAR
10K 250 watt SA (~300 hours) 895.9 PAR
14K 250 watt SA (~600 hours) 426.4 PAR
20K 250 watt SA (~300 hours) 437.2 PAR
I did a few other thing also that I thought people might be interested in. when i first tested the 14K bulb I forgot about the salt spray that had accumulated over the last two weeks. this reduced its out put from 426.4 to 327.7 so keep those bulbs clean :mrgreen:
I also put a chunk of 3/16 glass between the bulb and the sensor to see how much glass reduced the light and it went from 426.4 to 421.3
the last thing I did was to clean the algae off my tank sides to increase the turbidity and see how that affected it. the light decreased from 426.4 to 385.5 (my glass was pretty dirty :mrgreen:
anyways one thing that struck me funny and I guess some of you are probably wondering about is how close together the 14K and 20K bulbs are to each other. I was very surprised as i expected the 14K to be about midpoint between the 10K and 20K bulbs, where in fact the 20K is actually higher than the 14K. If you are trying to chose between these bulbs you can base your decision on looks as the PAR values are very close.
The SA 10K was the impressive result. it posted the highest number (even if it was against a AB bulb that was used for 2 years) the only thing I do not like about this bulb is the slight green hue that I get on my sand bed from it. other people have reported it as being to yellow to them and others have said it is nice. The main factor left on this bulb to be determined is the life of the bulb and how it reacts over that life.
for this question i will be switching back to the 10K bulbs on the weekend and i will start a monthly test of the PAR output and I will take a monthly picture using a set setting on my camera so i can see if there is any visual change in the bulb.
Steve
this test was conducted using the identical set up and the only thing that was changed was the bulb its self, and then the meter was positioned to the optimal position under the bulb but remained the exact same distance under the bulbs.
the set up for this test was a sensor mounted to an acrylic frame in my tank. the top of the sensor was 4" under the water and the distance from the bottom of the bulb to the water surface was 7". this made a total distance of 11" from bulb bottom to sensor top. also it should be mentioned that the ballast is an Advance M80 HQI ballast.
http://members.shaw.ca/steve-sherri/testholder.jpg
anyways back to the data. I tested a 2 year old AB (as a reference. wish I had a new one but I am going to order some in the fall) and the sun aquatics 10K, 14K, and 20K (I tested two of each bulb and took the average value as they were all very close)
OK
10K 250 watt AB (2 years old) 767.9 PAR
10K 250 watt SA (~300 hours) 895.9 PAR
14K 250 watt SA (~600 hours) 426.4 PAR
20K 250 watt SA (~300 hours) 437.2 PAR
I did a few other thing also that I thought people might be interested in. when i first tested the 14K bulb I forgot about the salt spray that had accumulated over the last two weeks. this reduced its out put from 426.4 to 327.7 so keep those bulbs clean :mrgreen:
I also put a chunk of 3/16 glass between the bulb and the sensor to see how much glass reduced the light and it went from 426.4 to 421.3
the last thing I did was to clean the algae off my tank sides to increase the turbidity and see how that affected it. the light decreased from 426.4 to 385.5 (my glass was pretty dirty :mrgreen:
anyways one thing that struck me funny and I guess some of you are probably wondering about is how close together the 14K and 20K bulbs are to each other. I was very surprised as i expected the 14K to be about midpoint between the 10K and 20K bulbs, where in fact the 20K is actually higher than the 14K. If you are trying to chose between these bulbs you can base your decision on looks as the PAR values are very close.
The SA 10K was the impressive result. it posted the highest number (even if it was against a AB bulb that was used for 2 years) the only thing I do not like about this bulb is the slight green hue that I get on my sand bed from it. other people have reported it as being to yellow to them and others have said it is nice. The main factor left on this bulb to be determined is the life of the bulb and how it reacts over that life.
for this question i will be switching back to the 10K bulbs on the weekend and i will start a monthly test of the PAR output and I will take a monthly picture using a set setting on my camera so i can see if there is any visual change in the bulb.
Steve