# How well do "conversion" bulbs work?



## DonJones (Jul 26, 2009)

I have been seeing "conversion" HID bulbs (HPS that will work with a MH ballast and vice versa) listed on the Internet sites.  Does any one have any experience with them?

I'm pretty sure that they under preform by about 10% IE a "400" conversion will actually put out at "360", at least that is what I'm reading in the specs.

My main question is whether or not there is more than 10% difference in the performance for a given stage, like MH for veg and HPS for bud, so that it would be worth using a 360 watt bulb of the opposite type during those stages.

For example, I'm just getting started and have 4 magnetic ballasted 400 watt MH lights set up with $80 each invested.  Now I know most people say HPS will give bigger buds faster than MH.  What I don't know is whether the difference is worth spending $40.00 to $50 per light to put the HPS conversion bulbs in and only get 360 watts of the HPS spectrum per light .

Is the improvement going to be worth the trouble and money or am I just better off to save my money up and start buying some switchable electronic ballasts and replacing my old magnetic single mode ballasts?  I know the electronic ballasts are a lot more efficient than the magnetic ones and run a whole lot cooler.

Also, I'm hearing a lot about high output T-5s that give off nearly the same spectrum as HPS with no where nearly as much heat or electrical load.  How do they work, assuming of course that you are getting the same amount of light by using more lamps to equal the output of the HPS?

Thank you for sharing your experiences and knowledge with me.  I know a lot about a lot of things, but growing medicinal marijuana is NOT one of them.  I'm still learning rapidly and the more I learn, the more I find that I still need to learn.

Don Jones


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## phatpharmer (Jul 26, 2009)

I use a Hortilux conversion bulb in my 1000w MH and I haven't had any problems with it, Its actually rated 960w but still puts out 130000 lumens witch is pretty good!


                                                 Phatpharmer


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## pcduck (Jul 26, 2009)

I would save my money for upgrading the ballast. I did a mh grow start to finish and had some nice buds. Afterwards I upgraded to a 600 watt lumatec and use my 400 watt mh for veg cab.


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## DonJones (Jul 27, 2009)

phatpharmer,

Thank you for the quick response.  

Have you tried to bud with a MH so that you can compare how much difference using the HPS conversion bulb made?

Don Jones


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## phatpharmer (Jul 27, 2009)

Sorry Don no I haven't flowered with MH only the Conversion bulb and a HPS.



                                        Phatpharmer


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## BBFan (Jul 27, 2009)

Hi Don-
I use some old 400 watt magnetic ballast units also- sounds like the same set-up you're talking about.

My first grow I used only one unit and didn't get a conversion bulb until the last 3 weeks of an 8 week strain.  The buds continued to get bigger after replacing the MH with the conversion bulb- but I can't say that they wouldn't have gotten bigger under the MH anyway- they always pack on the most weight during the last few weeks.

Growdude (a well respected grower here) has done a full grow under MH and says he could barely tell the difference from the same strain grown under HPS- the buds may have been a bit smaller but appeared to have more trich development.

As far as lumens go, the 360 HPS actually puts out more lumens than the 400 MH- which IMHO is always a good thing.

Bottom line, there are alot of growers who insist that HPS is the only way to go, but I really haven't seen any data to back it up.  I'm preparing a grow now (working out some heat issues as I am adding UVB lighting), and I plan on using more MH as everything I've read indicates that MH, while producing slightly smaller buds, does produce more THC than HPS- and isn't that what we're after anyway?

With 4 units- you will be able to grow a lot of herb- I just finished a grow under 2- 400 watt units that yielded 12 oz of finished product.  I guess it depends on how much you want to produce.

Can't help you with the T5 question as I have no experience.

Good luck to you and be safe.


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## DonJones (Aug 6, 2009)

It looks like I may have solved my own problem.  My sister found and add for 400 watt HID multi voltasge commercial lights for $25 each.  When I called about it, the guy said he was replacing the lights in his shop and the electrician told him that they were sodium.  I'm going to check on them tomorrow.  I would like them to be higher wattage but since the entire price is about what a bulb would cost commercially, I can live with 400s.

*Question:* How many 400s do I need to cover a bud room measuring 12' x 12'?


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## ShecallshimThor (Aug 6, 2009)

i would use 4 but i think you could get away with 3


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## purplephazes (Aug 6, 2009)

DonJones said:
			
		

> It looks like I may have solved my own problem. My sister found and add for 400 watt HID multi voltasge commercial lights for $25 each. When I called about it, the guy said he was replacing the lights in his shop and the electrician told him that they were sodium. I'm going to check on them tomorrow. I would like them to be higher wattage but since the entire price is about what a bulb would cost commercially, I can live with 400s.
> 
> *Question:* How many 400s do I need to cover a bud room measuring 12' x 12'?


5000 lumens per sq foot (not watts )take care !


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## pcduck (Aug 7, 2009)

> Question: How many 400s do I need to cover a bud room measuring 12' x 12'?




If my math is right and if you  want 5000 lumens/sqft you would need 16 lights at 400 watts to cover your area.


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## The Hemp Goddess (Aug 7, 2009)

DonJones said:
			
		

> Also, I'm hearing a lot about high output T-5s that give off nearly the same spectrum as HPS with no where nearly as much heat or electrical load.  How do they work, assuming of course that you are getting the same amount of light by using more lamps to equal the output of the HPS?



What you have heard about T5s is not quite right.  While they are the highest output of all the fluoros, watt per watt and lumen per lumen, they still do not beat a HPS.  A 54W T5 puts out 5000 lumens.  And when you start getting banks of them, they are going to be as hot as a HID light.  I use them in a small veg space to veg and am very happy with them.   There have been growers here that have gotten great results flowering with T5s, but it is a misconception that (lumen per lumen) that they would be cheaper to run and cooler than HIDs.

I also came up with about 16 400W lights for a 12 x 12 space.


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