ok, so what's my light output likely to be equivalent to...100W with no reflectors, 125, 150...?
What's my wpg?
- Thread starter nickmcmechan
- Start date
I would think the WPG rule takes reflectors into account. I think what you have is what you have.
Plecosterone
We don't need no stinking badges!
If you have 75W, your light is equivalent to 75W. With 100% reflection into the tank, you have 75W of light into the tank. Without reflectors you have 75W of light but only about (just a guess) 40W of light going into the tank. There is no getting aroung this one.....you have what you have and it is a matter of directing what you have to either grow plants in the tank or light up a room.
if you want to increase available light to all parts of your aquarium, simply winkle up some aluminum foil and coat you reflectors with it. Will bounce light like crazy. And it's safe.
Plecos. was being a bit literal there. You can get 100W of light out of 50W of bulbs as it applies to the wpg rule of thumb. For example T5HO with ideal reflectors will give you about double the light into the tank compared to T12 with flat reflectors. This is because the T5 is more efficient. No, the actual wattage consumed will not be less or greater than its suppose to be, but the light getting to the tank will be which is what WPG references. But WPG is just a ballpark estimation of how much light to aim for (wattage isnt light, after all).
The only way to know for sure is using a good light meter, one that measures PAR of PPFD.
Yes reflectors are very good. The WPG rule of thumb is based of T12 lighting with flat reflectors I believe. Meaning if you had no reflector at all you would need more wattage to get the equivalent WPG. Or if you had a really efficient setup you might be able to get away with less. It isnt an exact science (unless you have a PAR meter)
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The only way to know for sure is using a good light meter, one that measures PAR of PPFD.
Yes reflectors are very good. The WPG rule of thumb is based of T12 lighting with flat reflectors I believe. Meaning if you had no reflector at all you would need more wattage to get the equivalent WPG. Or if you had a really efficient setup you might be able to get away with less. It isnt an exact science (unless you have a PAR meter)
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thanks loaches, guess i/m somewhere in between, the reflectors are not flat but parabolic...i'll gues i have the equivalent of 2 wpg then.
the lights are t12
the lights are t12
I'm just stepping into this thread, but having read over what has been said, others have clearly stated that the reflectors are not giving you more light than you already have. They are merely redirecting light that was otherwise being wasted back into the tank. You do not have the equivalent to 110 watts of light from 75 watts worth of fluorescent tubes. The WPG rule accomodates reflectors, as it would be a waste not to use them. (seriously, what fixtures nowadays DON'T have reflectors?) The efficiency of your reflectors brings you closer to the true 75 watts your lights are putting out, but does NOT exceed that 75 watts of light. The same setup with no reflectors delivers perhaps 35-40 watts of the available light into the tank. Your setup with the reflectors delivers nearly the full 75 watts of light into the tank, no more. I have an overdriven ballast in my current fixture, pushing my 40 watt bulbs to 55 watts per bulb. My fixture has a reflector, but in all likelihood, I'm probably only getting 45ish watts per bulb into the tank. You also have to accommodate for water depth, water clarity, how dirty the glass is between the bulb and the water, how much surface agitation the water has, (yes, that actually affects incoming light) so on and so forth. There are a LOT of factors that go into a true WPG calculation... generally its used as a loose measure of approximation. If you want more light in the tank, you need to add more light, not some fancy (and likely overpriced) reflector.
