Question:

Cheers Anthony, Hey we are having a discussion in our club as to which bulb is better long term. I know you can overdrive the T5'S and get some wonderful lighting. I still contend that the t5's don't have the intensity that the halides have. Let us say that we are lighting a 24" deep tank and one person uses  250watt halides vs. comparable t5's for an SPS TANK, which do think will have a higher PAR? also for value doesn't overdriving the t5's take the life out of them earlier?If there is a thread that you think will be of some value could you point me to it. Grazie,

Reply: indeed it is a case by case issue to some extent relative to the needs of the corals at the depths they are to be kept at. And we cannot dreag PAR into it so easily relative to transmission of the light at depth as in this example here.

What we can speak to however is the amount of light produced per watt and "value" of it with regard for lamp life etc.

On those points and with your example of a 24" tank with needy high light sps corals... MH is the better value here by far. Most MH lamps last longer (better trueness of color over most all of the lamp's lifespan for many/most MH lamps) than most any fluorescent lamps. They also penetrate the water at greater depth.

As such... MH is a better "value" in terms of the amount and quality of light produced per watt consumed and is a no-brainer for deeper tanks IMO in particular.

That said... I do use VHO and PC lights currently as well as MH on some of my aquaria since "value" is not the only influence on my lighting option needs and choices.

Very good question though... quite worthy of its own thread (off PM).

Anth  

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Anthony Calfo