new lights

[jc]

o.k. I should have listened to you guys and got MH to begin with. Instead I went with another PC hood. Now I am upgrading my 75g to a 90g and I want to switch to MH lights. The 2 PC hoods are going to my new 180g fowlr tank, woot! I would like to have MH so I could try to keep some sps and maxima clam. The canopy is a perfecto that is 9" from the inside to the lip of the tank. Could I use two 175w bulbs retro kit with no glass cover? I want to get the best color out of my zoos and lps. My budget for lights is $300.

[snoop]

If the are DE then you dont need glass to block radiation.

[jc]

I meant the glass canopy that came with the tank. Is DE the one sided type bulb? I have seen that type and the type that has metal on both ends.

[akm]

If the are DE then you dont need glass to block radiation

Actually its SE bulbs that don't need glass. DE-double ended, SE-single ended

[alton]

I have 2 - 175 MH with electronic ballast on my 75. I retro-fitted a custom sealife orbit fixture and added an additional fan that I keep on the glass tops. I decided to keep the glass tops on because my Regal Tang thinks he is a Big Mouth Bass and loves to splash. My lamps are 2 1/2" from the glass tops and with the coral life 4" fan cooling the glass tops I have no problems with heating. I have about $350 invested. My lamps are 30% brighter with the electonic ballast verses the Magnetic ballast I first used. Both Ushio and Coral Vue 175 mhw lamps are made for electronic ballast. Make sure you match the lamp to the ballast.

[GaryP]

There are three problems with using the glass cover that comes with a tank. The first is cooling. A tank operates as an evaporative cooler. If the water surface is not exposed to moving air, evaporation does not take place efficiently and temp. tends to be a problem. Two is keeping it clean. I have enough problems keeping my center brace clean. Three is absorption of light. Even if it is clean, standard class is still going to absorb a fair amount of light being transmitted through it. We spend a lot of money on the lights and electricity to run them, you don't want to give it away.

Obviously alton is using glass and it works for him. I am not discounting what he is doing, he has good reasons for using glass. Fish that splash water on a hot MH bulb can cause it to explode. What works for one tank may not work for everyone. Alton probably knows more about lighting then anyone I know and I'd never second guess him. You may want to give it a try with and without the glass and see what you think.

Just to clarify some of the earlier posts that may have been a little confusing. The glass on single ended bulbs are made from a glass that absorbs UV light produced by the bulb. THe double ended bulbs are made from a thinner glass and do not absorb UV. They are used in a reflective fixture that comes with a glass pane that is UV absorbent. The better fixtures use a special glass that is low in iron and sulfur (similar to that used in SE bulbs) that is almost 100% transparent to everything except UV.

I hope that helps.

[alton]

Do not ever use a DE lamp without UV lenses. One of the Coral magazines has a great (or bad) article of what happens to your fish when the lens is not used. It's called blindness and death! I keep my thermostat here in my office at 74 with a water temperature at 78.

[GaryP]

UV will burn your corals too. UV light causes cataracts in humans. I wouldn't think it would be different in fish.

[jc]

Thanks for the info guys. I plan on going with an SE bulb set-up with no glass canopy. Can I attach the bulbs and reflectors to the wooden canopy or do they need to hang? Also what type of bulb brings out the best colors? Do I have to add a Vho or pc actinic light because the MH hoods all seem to come with them. Where should I buy my kit, I have used hellolights for pc bulbs and I was pretty satisfied with them.