Quick question(S) about metal halides

[jason the filter freak]

1. Is HQI and DE the same? If not whats the diffrence?

 

2. What are the partiular advantages/disadvantages between double ended and single ended.

Which costs more?

Which has better output?

Which are easier to find retro kit's for?

[akbuuur]

double ended is the same thing as HQI- i have no experiance with them, however i hear that HQI are supposed to be better for long term- they last longer. Id be interested in the answers as well.

[Guest JasonD]

1. Same

 

2. SE bulbs have UV sheilding as part of the bulb, DE bulbs need a separate UV shield. I believe DE may give more PAR, but it's probably more an academic question as not to many folks complain their SE MH bulbs are not growing coral. SE is probably cheaper than DE.

Edited June 15, 2007 by JasonD

[traveller7]

1. Is HQI and DE the same? If not whats the diffrence?

 

2. What are the partiular advantages/disadvantages between double ended and single ended.

Which costs more?

Which has better output?

Which are easier to find retro kit's for?

1. Double ended is a bulb format relating to the socket type(70wt, 150wt, 250wt, and 400wt all use a diff socket lengths). HQI is a legacy designation more indicative of a ballast type, specifically impacting "start up" requirements. Most if not all hobby DE bulbs require a "HQI" type of starter circuit(HXPF etc) or the use of an electronic MH ballast.

 

2. Single ended typically allow a single reflector to be used for 175/250/400 mogul based bulbs, unfortunately such flexibility comes at the cost of reflector optimization. Mogul bulb+Ballast+reflector combinations tend to be cheaper then DE, but the bulbs themselves tend to be a wash in cost. DE ballasts tend to be more expensive, but a moot value if you are using electronic ballasts.

 

IMHO mogul is more flexible to reconfiguration but DE tends to be more efficient in PAR to coral.

 

Hit the stickies in the Lighting forum on RC for more information then you would ever want to know O.o

 

Choose your poison

[davelin315]

Piggybacking on Scott's reply, from my research, I have found out several things. First, as Scott said, HQI refers to ballast type. You can run SE bulbs on an HQI ballast. That said, an HQI ballast is not necessarily an HQI ballast. That sounds funny, but some of the ballasts are not actually what they say they are. For instance, the 400W HQI ballasts are generally not actually HQI, they are sodium vapor or something like that. They are also not 400W, but are over 400W. The real HQI ballasts are not produced here yet at our voltage. I'm not sure if this applies only to 400W or all of them.

 

For my tank, I intend on running 400W SE Helios 20000K bulbs on a 400W PFO HQI Ballast, not DE bulbs.

 

As far as the bulbs themselves, I have heard that the 400W DE bulbs are not worth it. The 250W DE bulbs supposedly outdo many 400W SE bulbs, but they also have better reflectors developed for them and also higher end bulbs. The 400W DE bulbs are not advanced yet and the reflectors are not as good as the ones that are available for 250W DE and so they don't have as much output.

 

Now, of course, I did this research a year ago, and things have a habit of changing very quickly in this hobby, but I think the info is still sound.