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Old 05/04/2014, 03:56 PM   #5
Acropora Gardener
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Join Date: Dec 2009
Location: Sheffield, UK
Posts: 2,759
The Light Specification

I use a combination of T5 (ATI Sunpower 6 X 39W) and LED (2 X TMC Aquaray Reef Blue):

I experimented with a number of tube combinations, such as:

Front ATI Blue + ATI Purple + ATI Blue + Sylvania 6500K ATI Blue + ATI Blue + Back

front ATI blue + KZ Fiji purple ATI blue + Sylvania 6500K ATI Blue + ATI coral + back

Front ATI Blue + KZ Fiji purple ATI Blue + ATI Aquablue special ATI Blue + ATI Coral + Back

My present tube combination is as follows:

front ATI blue + ATI coral + ATI blue + ATI coral + ATI blue + ATI coral + back

This, in my opinion, is by far the best combination in terms encouraging both the fluorescent and reflective pigmentation of corals. It encourages very good growth too. Dennis (TropTrea) kindly provided the spectrum graph for this combination. It is slightly heavy on the red spectrum, but visually it is very pleasing, especially when combined with the blue LEDs.

Finally, I carried out an experiment to determine the best fan speed for my ATI unit to ensure that the T5 tubes run the most efficiently. Literature suggests that for the most optimum efficiency the ambient temperature at the label end of a T5 tube needs to be 35C. If a T5 tube runs in a cold setting, then the PAR output will drop. If, on the other hand, it runs hotter than 35C, it will look brighter, but is longevity will drop.

My experiment was a simple one: I measured the "temperature of the air coming through the cooling hole, not the tube temp at the cooling spot", i.e.

Here are the results:

When the fan speed was set at 9V, I measured:

The following day, when the fan speed was set at 7.5V, I measured:

In the end I settled with the 9V setting. This is consistent with advice given by The Grim Reefer when he was involved with the great T5 thread.

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65G SPS Reef- ATI 8 X 39W PM; TM [NP-Bacto-Balance; A-; Reef Actif]; GAC; Ultra Phos
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