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[APD] Re: Help with lighting chocie

Hi...I'm new to the list and have a question that has been driving me nuts
for the last few weeks. I have a 155 gal bow front tank, 72 inches long, 24
inches deep. I am going for a high tech planted tank, flourite substrate,
dupla heating cables, pressurized C02, heavily planted from the start, medium

Excellent start!
fish load. I just can't figure out the light specifications. I'm looking for
3 to 4 watts per gal., realizing that that's not the best measure but a
guideline. Here's my question...assuming cost is not the largest factor
(plays a role but the the starring role) what makes the most sense for the
plants. Power compacts alone ??, power compacts and metal halides ? VHO ??? I
need to have the lights on the tank, not pendants..I have cats and don't want
my "catfish" to be of the 4 legged, burned to a crisp variety ( maybe I'm
over reacting but they love walking on top of the tank now and there's no way
to stop them as the tank is next to a shortrise stairway, hence easy access.)
MH is really best with an open-top tank, so if you can't use an open-top setup then MH probably isn't your best choice. The difficulty with using MH in an enclosed hood is getting rid of the heat (which usually also means a lot more water evaporation from the tank and more resulting top-offs), protecting the bulbs from splashes, and getting sufficent spread of the light to avoid large shadow areas in the tank. The MH reflectors really work best when they are suspended higher above the tank than a typical enclosed hood will allow.

I'd stay away from VHO. VHO is an older technology and has the highest ongoing maintenance cost in replaced bulbs than any of the three light types you mentioned.

Power compacts are probably your best bet. Heat is less of an issue with them, which also helps with the "protect the bulbs from splashes" part since it allows shields and lens to be made of plastic in most cases. They also have a much longer bulb life (several years, I get about 3 years on my 55 watt fixtures) than VHO. The shape of the light bulbs allow easy, even lighting of tanks even when using the lights very close to the water's surface. I think you'll have the best luck with the power compact setups.

Any help ? Are MH over kill. I seem to be able to only find system's that
have 3 75 watt MH's or 3 MH's and PC's..or VHO's. Would power compacts give
the same effect as the MH's. I always loved the ripple effect of lighting
with Mh's but since the water movement in this tank needs to be kept to a
minimum,(not dirving off C02) then am I paying for an effect that I will not
even see if I got the metal halides for the "glitter" effect alone ?
Three 175w MH lights is a typical configuration for a 72" long tank. MH fixtures are generally said to provide good lighting for about a 2 x 2 foot square area, and the higher wattage bulbs cover the same area but can get enough light into deeper tanks. 175w is usually good for a 24" deep tank. If you get a hood with some room inside (which will probably mean a wooden hood), you should be able to fit PC lights inside in whatever arrangement works for you. http://www.ahsupply.com has a good selection of parts and very reasonable prices. You can save a lot of money this way if you have the time and are comfortable working with simple electrical devices.

Only MH and other point-source lights (single, bright, relatively small bulbs) will provide the ripple effect. You won't get the ripple and glitter with any of the fluorescent. I have been able to use a few small halogen lights as "accents" to provide a little of the water ripple effect, but I don't think it's worth the effort. You *will* get the ripple effect if using MH, even with a calm tank. *any* water movement will make some ripple effect. I used to get this effect just from fish swimming near the surface (and yes, the fish do cast shadows) in a tank that had no water movement at all.

Any help or suggestions would be tremendiously appreciated as I have now
entered over-analysis paralysis !!! Thanks in advance

The list is usually happy to help change paralysis into information overload ;-)


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