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Re: AH Supply Lights for moderate light on 75 gallon
Ty Cole is wondering about lighting his new aquarium with compact
fluorescents from AH Supply. Having been down the same road with my 130
gallon tank a few years ago, I understand his confusion. How much light is
enough, how efficient are these new bulbs, how to design the lid, how to
decide which color temp. bulbs to use, etc?.
Kim Bryant, owner of AH Supply, should be your first advisor. He won't steer
you wrong, nor oversell you - when I contacted him for my own needs, he
advised me to scale back my thoughts on how much light I needed (I was
initially thinking of 9 x 55W for my 72"x18"x24" tank, but followed Kim's
suggestion to go with 6 x 55W and it has worked out perfectly for my
A "standard" 75 gallon aquarium is 48"x18"x20". The 55W Bright Kit tube is
about 22" long and will light up 24" of tank length. The 18" width of the
tank will really need 2 tubes to provide even lighting, front to back so you
would end up using 4 x 55W tubes to evenly light the tank. The 96W tubes are
better suited to 36" long or 72" long tanks, due to their 34.5" length. In
my case, using the 96W bulbs would have resulted in a bit more light
(4x96=384W) as opposed to what I ended up with (6x55=330W), but I'm happy
with what I have, and so are the plants. The reflectors provided by AH
Supply won't really provide sufficient spread to cover the 18" width of the
tank if you only use one tube over an 18" wide tank. But don't try to modify
the reflector - it is designed to get maximum brilliance out of the tube and
with an 18" wide tank you are probably going to need 2 reflectors, front to
When dealing with lighting of this quality and this quantity, more is not
necessarily better. More light can push your tank into a range which
requires much higher maintenance and much more finess with the maintenance
of the correct balance between light and nutrients (CO2 + macro +
micronutrients). Its your tank, so you decide - either way will work, but
what is your level of expertise and comfort?
Since you are going to be building a custom hood, it should be an easy thing
to build in enough flexibility to add or subtract tubes as you need/want.
For example, you might decide to start with just 2x55 and see how things go.
It is easy to add 2 more bulbs into a custom made hood. For my own tank, I
made a hood which is basically an open box resting on the top lip of the
tank and which has 3 "doors" which are hinged at the back and lift up - the
lights are affixed to the underside of the "doors" in the lid. If I ever
decide to add more lights, I merely have to reposition the existing
relectors and screw in the extras.
As for color temp., your plants aren't going to notice much difference
between the 5000K tubes and the 6700K tubes (I have both). To my eyes, the
5000K tubes look "sunny white" while the 6700K tubes look "pure white", but
that is a purely subjective call on my part (white is defined as 5000K). In
a plant tank, where tannins can sometimes build up from the use of cork
and/or driftwood, the extra "whiteness" of the 6700K tubes can be a visual
plus. But again, your plants won't care, one way or the other. If you go
with 4x55W, you might wish to experiment with 2 of each color temp.
I can't comment on the use of a cover glass between the tubes and the water
surface. I know that they are recommended, but I don't like them. The
"center of tube to water surface" distance in my hood is 4.5" and I haven't
noticed any problems with splashing or condensation. I do have to wipe down
the reflectors every few months but this is easier than removing a cover
glass and washing it every week. Your mileage may vary.
Good luck. The AH Supply Bright Kits are an excellent value and you should
be very happy with them. Dealing with Kim is a pleasure and he's one of the