20k 400 watt Radium...when to replace?

[The Saltman]

Hi guys,

When are you supposed to replace the 20k 400 watt Radium bulbs? Do they last 1 year?

[DesertBandits]

Not an MH user, but I thought Ive heard people replacing them after 8mos, even as early as 6.

[Znut Reefer]

If you are using the Radium, you need to replace them after 6 mos. If you are using the XM's 20K you'll need to replace them every 12 mos. But also depends on what ballasts you use.

[cweder]

Six to ten months depending on how many hours per day. Your coral should give you some idea too.

[The Saltman]

<a href=showthread.php?s=&postid=11348708#post11348708 target=_blank>Originally posted</a> by znut Reefer
If you are using the Radium, you need to replace them after 6 mos. If you are using the XM's 20K you'll need to replace them every 12 mos. But also depends on what ballasts you use.

Are xm20k's close in terms of color and growth of the radium 20k?

[Znut Reefer]

Yes IMO And they last longer.

[sjfishguy]

wasn't there a recent article citing the output of a bulb vs life in months (can someone link this please, I wish I saved it) It basically said that after 6 months a bulb is 70% of its original intensity and after 2 years its like 60% its original intensity (something like this, again, I don't have it in front of me). The point was either replace them every 6 months (which most people don't find practical) or replace them every two years.

[The Saltman]

Yeah, but I think it was about the phoenix 14k bulb. I'm not sure that it meant all the halide bulbs

[Nanook]

8-9 months worked for me with Radiums. They do start to shift around 6-7 months.

[gasman059]

<a href=showthread.php?s=&postid=11349210#post11349210 target=_blank>Originally posted</a> by The Saltman
Are xm20k's close in terms of color and growth of the radium 20k? Used both over the years-currently run xm 's

IME color is about the same par is better with XM's plus u can run the xm's for about 12 months vs.6-8 tops on the radiums on normal regular photoperiod.

HTH

[Rickyrooz1]

<a href=showthread.php?s=&postid=11349195#post11349195 target=_blank>Originally posted</a> by cweder
Six to ten months depending on how many hours per day. Your coral should give you some idea too.

What do you mean by the coral will give me an idea? Will the colors become more pale or will I notice a decrease in growth as the bulb ages and needs to be replaced?

[silvers]

There has been a new study where they have shown that MH bulbs after ther first 3mo dont loose much par. until 18 to 24 mo. you may have some color shift but. Or you could get a LUX meter and see for yourself

[Kip]

i asked sanj once... he recommended swapping out bulbs when ppfd dropped to 80% of original output... of course you will need a quantum meter to determine this

as far as 400w radiums on pfo hqi... when i ran them (9-10hrs/day)... i could start to tell the difference around 5 months and by 6 months i would swap them .... on eballasts and other mag ballasts i'd expect you could get 9-10 months out of them

... with 14-20kk bulbs... you can usually see spectral shift along with the loss in ppfd output... but looking at your tank daily can desensitize your eyes to the shift

another trick for the thrifty tank keeper is to get a lighting system "too strong" for your tank... run the bulb at 18" for a year... then go to 12"... then after 6-8 months go to 8".... its a good way to get 2 years out of a bulb... works well with 10kk or less bulbs ( i do this over a frag tub )

[PITSTOP]

I switched from 400w Radium 20K's to the 400w XM 20K's and have been dissapointed by the switch...

I have new Radiums on the way...the XM's were nice and rich for the first few weeks then fizzled...very low intensity and blah colors...however, this could be due to the ballasts I'm running the XM's through - PFO HQI's - they could be overdriving and killing bulb life.

[orientalexpress]

I have new Radiums on the way...the XM's were nice and rich for the first few weeks then fizzled...very low intensity and blah colors...however, this could be due to the ballasts I'm running the XM's through - PFO HQI's - they could be overdriving and killing bulb life i agee ,i try helio 20k ,i'm happy with it so far.but the intensity is not as great as aqua connect tho.

[twon8]

<a href=showthread.php?s=&postid=11354590#post11354590 target=_blank>Originally posted</a> by PITSTOP
I switched from 400w Radium 20K's to the 400w XM 20K's and have been dissapointed by the switch...

I have new Radiums on the way...the XM's were nice and rich for the first few weeks then fizzled...very low intensity and blah colors...however, this could be due to the ballasts I'm running the XM's through - PFO HQI's - they could be overdriving and killing bulb life.

yeah, you get less out of the xm's on hqi; they are designed to run on magnetic ballasts, so dont' run them on hqi. less par, less life.

[jay24k]

What magnetic ballast is recommended?

[trueblackpercula]

I have 400 watt XM on an Icecap electronic ballast. They seem to be doing ok but nothing like the helios bulb. to bad they do not last on a electronic ballast or i would still have it. I have alos had the 10k ushio 400watt very bright but it turned yellow fast.......Sps loved the PAr and had fast growth with it. here is a current picture of the tank with 400watt XM bulb and 150 of actincs.
Michael
http://reefcentral.com/gallery/data/500/42064mini-RIMG0001.JPG
http://reefcentral.com/gallery/data/500/420643333.JPG

[ROBZ]

I replace my Radiums every 7 to 8 months as well... but run for 7 hours a day