175single ended have dismal outputs.
Heres the general rules of thumb:
Double ended bulbs have almost double the output of the same K bulb at same wattage. So a 150wattDE has more output than your 175watt. Most DE 250wattMH have the same output as 400wattSE bulbs. And on top of that, higher K bulbs in the 20,000K range have half the output of the same wattage bulb in a 10,000K. That means that a 400wattSE Cool Blue Radium (called a 20,000K, but measured at 38,000K) can have it's output challenged by that of a 10,000K 150wattDE. 175wattSE bulbs? Waste of space IMO. Minimum, 150wattDE, for an 18"tall tank like a 29 gallon, 250wattSE, if not a DE bulb would be your best bet. And FWIW, those old-style 'bell' shaped pendants are very innefective. 'back in the day' , before specialized pendants and reflectors were available, and aquarium specific bulbs were readily available, bell pendants worked because the more common 'industrial' rounded bulbs had a dispersion that worked well with a vertical orientation, like the ones still used when you go to places like Home Depot and look up. Now, aquarium bulbs have specialized 'side discharge', and are made to work in horizontal fixtures. To sum it up, the bell style reflectors waste something like 20-40% of the bulbs output. Not worth it. The quality of those ballasts is pretty cheap as well.
http://www.premiumaquatics.com/Merc...Product_Code=PFO-HQI250SYS&Category_Code=PFOp
this is a good 250wattDE system. You could prolly part it together on the same site like I have...
Icecap 250wattBallast (new style) $115
PFO Mini 250watt Hood only - double end $94
20K 250watt Metal Halide Bulb - CoralVue $57...most bulbs like this are in the $80-90 range, but I keep hearing good things about these bulbs...so....
This would be an awesome lighting system with 'top-shelf' components that would grow anything you want from shrooms to blue acro and clams. Just a little more, and much more received.
