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hahnmeister · 03/02/2008, 06:21 PM

Clams will do fine under T5s. In fact, I would bet they will get more light if at the bottom of a T5 lit tank than a halide lit tank of similar wattage.

Like I mentioned before, the perception of clams that need alot of light was developed years ago when lighting options werent very efficient. The only alternative to halide was a PC system... and PC systems suck at getting the required amount of light into the tank, you know? The sand in most PC lit reefs is lucky to be under 30-50 micromol's of PAR. With halides back then, getting 100 to the sand was good, and this would be sort of the minimum for croceas and maximas. This is where the perception came from.

Now, lighting systems can easily make light values in the 200's at the sand with the same wattage, even more so with T5s because they penetrate the water better. This is plenty for clams.

Oh, BTW, I would say a 8-10 hour photoperiod is ideal. I go 8 hours of halide+T5, with a one hour before and after of just T5s. I have gone as little as 8 hours with the T5s though (all on, all off) and been just fine. In nature, sure, the daily photoperiod might be about 11 hours, but much of that is 'off peak' like in the morning and late afternoon. During the noon peak, the intensities might be much higher than what we have in our tanks, but this is only for a couple hours, if that. For much of the day, our tanks tend to provide more than what they are getting in nature otherwise, and because of this, having a 10-12 hour photoperiod doesnt make the best of sense (unless you have very weak lighting you are making up for).

03/02/2008, 06:21 PM	#77
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	Clams will do fine under T5s. In fact, I would bet they will get more light if at the bottom of a T5 lit tank than a halide lit tank of similar wattage. Like I mentioned before, the perception of clams that need alot of light was developed years ago when lighting options werent very efficient. The only alternative to halide was a PC system... and PC systems suck at getting the required amount of light into the tank, you know? The sand in most PC lit reefs is lucky to be under 30-50 micromol's of PAR. With halides back then, getting 100 to the sand was good, and this would be sort of the minimum for croceas and maximas. This is where the perception came from. Now, lighting systems can easily make light values in the 200's at the sand with the same wattage, even more so with T5s because they penetrate the water better. This is plenty for clams. Oh, BTW, I would say a 8-10 hour photoperiod is ideal. I go 8 hours of halide+T5, with a one hour before and after of just T5s. I have gone as little as 8 hours with the T5s though (all on, all off) and been just fine. In nature, sure, the daily photoperiod might be about 11 hours, but much of that is 'off peak' like in the morning and late afternoon. During the noon peak, the intensities might be much higher than what we have in our tanks, but this is only for a couple hours, if that. For much of the day, our tanks tend to provide more than what they are getting in nature otherwise, and because of this, having a 10-12 hour photoperiod doesnt make the best of sense (unless you have very weak lighting you are making up for).