Is it possible (tank lighting question)

[MarkL]

Now I have my eyes on an AGA 90 gallon "Modern" series Oak tank and stand. My question is regarding lights. Every tank I saw that resembled this one had VHO lighting attached to the hood. It only looks like there is about 4-6inches of clearance between the hood and the water. It it possible to put Metal Halide lights in there (I thought I read at least 8" clearance was needed)? Also im a little curious how metal halide would affect temp in that closure even with 2 fans in the canopy. Anyone do that or should I just go with a different form of lighting?

[piercho]

I looked at the stand & canopy in AGA's 2001 catalog. You are going to have trouble getting a MH reflector fixture into that tight of a space. And with the hot HID lamps that close to the water, splashing (on the bulb) may become a problem, since it could burst the bulb.

Most people who want to use MH build their own canopy. There are plenty of plans that you can access by searching on the DIY page of Reef Central.

For instance, PFO parallel reflectors (hold both MH and flourescents) are 6.5" high. Adding a 1/2 inch air gap (the more air gap above the reflector the better for cooling) means you'd need a 7+" space between the top of the inside of your canopy and the water in your tank.

FYI, optimal spread on MH with most reflectors is with the bulb center 8 to 12 inches above the water. Perpindicular reflectors ("Spiderlight" and "Reeflector") spread the light most efficiently, but don't allow you to add flourescent lamps in parallel.

One simple option is to use MH pendants and no canopy at all. Heating becomes a mute point. Some people don't like the asthetics of this, and fish can jump out.

One fixture that can fit in a tight space is the mini-pendants for the Ushio/Hamilton 10,000K HQI bulbs. They are only 4" high and are fully enclosed (have a glass face). The lights are very good for coral and most people find the light color nice (blue enough) without any actinic flourescents. They are expensive: a complete ballast, pendant, and lamp fixture will cost you about $400. So $800 for 2 fixtures for your tank.

PFO is the lead manufacturer for aquarium reflectors and ballast kits in the US. You can find pictures of all the stuff talked about above
here: http://www.pfolighting.com/aqwebsite/aqhomepage.htm

Premium Aquatics is a very reputable distributor of aquarium lighting equipment, including PFO eqt. They also have a good discusions of tank lighting options on their web pages. Their lighting pages start here: http://www.premiumaquatics.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=PA&Category_Code=Lighting

It took me months to decide on my lighting setup. What lights you need ultimately depends on what your main tank inhabitants will be. Good luck.

One more note here. MH produce no more heat than flourescent bulbs in terms of PAR/watt. The heat is just concentrated since the heat source is less distributed (less surface area of lamp per watt), making it appear that the MH produce more heat. Since MH are normally mounted 8" to a foot above the water, meaning there is MORE air space than with flourescents, tank heating when using MH should actually be less of a problem.

Probably more of my opinion than you wanted.

[Doug]

Hi Mark,

I have seen the AGA modern series canopy in person and I feel that there is not enough room for MH lights. That canopy has even less room than the pine series that they make.

I agree with Piercho and building your own hood, pendants or a custom made hood would be a much better choice.

One small bit of advice. If you really want to use MH lights then try to get them from the start. I have wasted a lot of money upgrading my lighting over the last few years trying to use different lamps and standard canopies and still ended up buying MH in the end.

HTH

Doug