Metal Halide light questions

[dede]

Just getting into acros and want to change out the cheap, Chinese box lights I have been using to some metal halide lights I got with my original purchase of this tank.

I believe they are the large, lumenarc reflectors with 400 watt ballast and bulbs. I have 2 of them but could only find one working ballast.

Question is how far do I hang these above a 180 gallon peninsula tank that is 6 x 2 x 2. Pendants are large 20 in square by 9 in tall. Do I need to change the height if I change to 250 watts. I am also not using a hood.

I was thinking about getting the selectable ballast for the second reflector in case I do switch over to the 250 watt bulb. Any issues with these and recommendations for brands.

The other thing is that both reflector sockets have different wiring and plug in for the ballast. The one that works is spliced together I assume for the correct male/ female fitting to the ballast. Is this normal or a fire hazard. With the new ballast will I have to do the same thing and does the ballast come with both male female fittings. Any videos on how to change the wiring for plug fittings?

And lastly, I got a handful of 400 watt bulbs with the tank. Is there anyway of telling what bulbs are good and what ones are past using without a par meter. Guy was in the hobby for 10 years and I swear never threw anything out. A bunch of the stuff I got from him didn't work but I guess he was saving for parts.

 

[jda]

I would assume that all of the bulbs are used up. You can use them for a few days to see if you like the color, but I would have new ones coming soon.

Select a watt is OK if you are unsure of what you want. Some bulbs, like the 250w 20K radium will run better with different ballasts, but the select-a-watt will still drive them pretty well.

I would keep them up about 8" over the tank with 250s and maybe 10-12 with 400w. ...just lower then so that the spill is not too much.

Splicing is quite normal. I have just wire nuts and some electrical tape over some of mine. If you wanted to clean it up with some solder & shrink, then that might be good.

Are these going to stand alone, or will you be having some T5s or LEDs for supplements and dusk/dawn? If they are standalone, then I would look to 20K Radium either in 400w or 250w since they are probably the most often used bulb without supplementation.

 

[dede]

Thanks @jda for all the info. I would like to run T5s also but the pendants are so large there is now room along the sides. I probably will place the LEDs on the ends and between the 2 pendants for supplementation.

 

[jda]

Without supplements, then look at 20K radium or the new 20K Hamilton bulb in SE versions. They are good without any supplement.

Edit: you kinda need to pick bulbs that look good without supplements since it is hard to overpower a 250W or 400W Mh with T5s or ReefBrites. They can be very useful for dusk/dawn when the MH are off, though.

 

[mtraylor]

I'm a big fan of the 20K radium bulb. YOu will not be disappointed. I went and looked at my lumatek ballasts I used to use when I was banging the MH's and from the ballasts, my connectors have a water sealed connector that connects the mogul to the ballast. The only raw connection was connecting the wires to the mogul.