Problems With HID Light Coverage

[SirGrowAlot]

In a tent 4ft wide, 4ft deep, and 7ft high a 600W MH/HPS light is not covering all of the area. When the light is placed in the middle, there is a considerable amount of space not adequately lite up. This is my problem. I need to add in another light but there are issues with that. If I add in a LED or CFL there is an issue because of the distance they have to be from the light. They would have to be soo much closer than the HPS that they would actually block out alot of the light the other half of tent would have got from them. But then if I go with another HPS I run into heating issues. There is alrdy active exhaust and active intake but temps run about 80. The 600watt mh/hps i got alrdy is dimmable so what I was thinking was dimming it down to 400 and getting another 600watt dimmable mh/hps and putting it down to 400. This would cut down on the heat and also allow good light coverage, am I correct?
Please, if you have any other suggestions, help is gladly welcomed.

Thank you in advance for your help. And btw I want to thank all the great people on this site, I have never seen such a great community.

 

[SirGrowAlot]

After doing more research, I just discovered that the actual suggested area for a 1000W is 4x4ft. I also read that two 600 Watt lights would cost close to triple the amount in the monthly power bill as compared to a single 1000watt light. In other forums I have read how that in general 600watt lights are better than 1000watts in the ratios. But you would think the 2 lights would cover better than a single light.
Any suggestions?
Thank You

 

[too old]

Not sure how you arrived at triple the cost for two bulbs vs. one. Without taking into account the wattage used by the ballasts (which is supposed to be minimal in dimmables), your costs should be twenty percent higher (1200w vs. 1000w).

As to using two bulbs as opposed to one, you would have 1200w in 16 sq.ft. = 75w/sq.ft. If you dimmed them to 400w (50w/sq.ft.), this is pretty close to minimal, but, this number would be an average over the entire area. Depending on how you arranged the lights, you could get sufficient light to the perimeter, with a good overlap in the centre that would be more than enough.

However, these are just opinions and not proven in practice. More experienced growers would probably have a better idea.

Edit: you also have to take into account the density of your canopy. Even though the numbers say your wattage/sq.ft. is ok, the penetration of the lower watt bulbs may not be sufficient

 

[Goshawk]

I agree with too old that two 600 watt lights will use only twenty percent more power than a 1000 watt light.
As you have probably already read there is quite a bit of information on the web that says two six hundred watt bulbs are more efficient than a 1000 watt bulb and provides more light for the wattage. The way they come to these figures is since a 600 watt bulb is much cooler than a 1000 watt bulb it can be placed closer to the plants and therefore provide more light to the canopy. I bought into this theory and purchased 2 600 watters to go along with my 1000 watt bulb. I wish I hadn't because there is one big flaw to this theory and that is it takes twice as much space to get only two hundred more watts when using the 600 watt bulbs. So for me all the lights I buy in the future will be digital, dimmable 1000 watters. Also as a side note my plants are always happier with a higher wattage light placed farther away from the plants than with a lower wattage light placed closer to the top of the canopy.

 

[SirGrowAlot]

well im glad you all cleared that up for me because I too thought that seemed weird that 2 600watts would use that much more than a 1000. I had read it on a previous thread. but my biggest problem is not cost, it is heat. with my single 600watt in the 4x4 my temps are alrdy at the top of norm. Would a 1000watt dimmable set at 600w put out more heat than a regular 600?
So would you all reccomend getting a 1000watt but dimming down to 600?
What about adding a good CFL or a LED? I know they wouldnt not put out even half the heat, but the problem with those is that they have to be soo much closer to canopy than a HID, and since i already have the 600watt MH/HPS, putting a LED or CFL beside and and 7 inch below it woul block out half the light the other side of tent would have got.

I really do appreciate the help

 

[too old]

I didn't see in your posts anything that said you were limited to space used. If this is the case, you could split your grow into two 3x3 and use a second 600 watt bulb. You would end up with only two more square feet of space used, and have sufficient coverage with the 600 watt bulbs. The added capital costs would be minimal and you would have two happy places to go to.

 

[SirGrowAlot]

Well I kinda am limited in space used, bcuz it is an actual "tent" that is 4x4... Would two 600 watters in a 4x4 get too hott??

 

[Icemud]

I would suggest using 2x 600w bulbs vs 1x 1000w. The reason is with 600w lights you are getting more lumens per watt than a 1000w bulb, so its like this...

Generally a 1000w HPS puts out somewhere around 120,000 lumens...

Usually a 600w HPS puts out around 95,000 lumens....

so for 2x 600w you would be putting out roughly 180,000 lumens for only 200w extra... plus air cooled 600w lights will allow you to get them closer to your plants that 1x 1000. That is the route I would go.

Also if you get a dimmable ballast, if the temps get to hot, you could always turn one down.

even better yet, you could run 1 MH and 1 HPS for a better spectrum blend. From my experience MH bulbs themself's may be hotter on the glass surface, but they seem to put out much less "heat" than the HPS. Since HPS is loaded with a lot of IR band, there is more "heat" projected which will raise your ambient temps... Using 1 MH and one HPS should run cooler than 2x HPS...

 

[SirGrowAlot]

Icemud:
K man.. Thats what ill try to do..
What all things can i do to try to keep temps down? Bcuz I am already right at 80 with just one 600watt.. I already got an outake and intake, cool humidifier.. You all know of anything else I can do?
Do CFL's put out heat?? MOre or less than LED?

 

[Goshawk]

I would suggest using 2x 600w bulbs vs 1x 1000w. The reason is with 600w lights you are getting more lumens per watt than a 1000w bulb, so its like this...

Generally a 1000w HPS puts out somewhere around 120,000 lumens...

Usually a 600w HPS puts out around 95,000 lumens....

so for 2x 600w you would be putting out roughly 180,000 lumens for only 200w extra... plus air cooled 600w lights will allow you to get them closer to your plants that 1x 1000. That is the route I would go.

Also if you get a dimmable ballast, if the temps get to hot, you could always turn one down.

even better yet, you could run 1 MH and 1 HPS for a better spectrum blend. From my experience MH bulbs themself's may be hotter on the glass surface, but they seem to put out much less "heat" than the HPS. Since HPS is loaded with a lot of IR band, there is more "heat" projected which will raise your ambient temps... Using 1 MH and one HPS should run cooler than 2x HPS...

If getting more light to the plants is the main thing someone was trying to accomplish then 1000 watts is the only way to go. The reason is this using your figures of one 600 watt bulb putting out 95,000 lumens then two 600 watt bulbs will put out only 190,000 compared to 240,000 when using 2 1000 watt bulbs. They both take the same amount of space and when using using the 1000 watters you will get an additional 50,000 lumens to your plants over using the 600 watters. Believe me I found out the hard way and bought 2 600 watters which is also way more expensive. This is a perfect example of how real world application can be different then what the numbers on paper would seem to indicate.

 

[Icemud]

600w lights can be put closer to the canopy than 1000w, thus by the square inverse law, the lumen intensity of a 1000w light placed at 18" is the exact same intensity you would get out of a 600w at 15".... that is why 600w's are known for the best lumen to wattage ratio.

 

[Goshawk]

I would suggest using 2x 600w bulbs vs 1x 1000w. The reason is with 600w lights you are getting more lumens per watt than a 1000w bulb, so its like this...

Generally a 1000w HPS puts out somewhere around 120,000 lumens...

Usually a 600w HPS puts out around 95,000 lumens....

so for 2x 600w you would be putting out roughly 180,000 lumens for only 200w extra... plus air cooled 600w lights will allow you to get them closer to your plants that 1x 1000. That is the route I would go.

Also if you get a dimmable ballast, if the temps get to hot, you could always turn one down.

even better yet, you could run 1 MH and 1 HPS for a better spectrum blend. From my experience MH bulbs themself's may be hotter on the glass surface, but they seem to put out much less "heat" than the HPS. Since HPS is loaded with a lot of IR band, there is more "heat" projected which will raise your ambient temps... Using 1 MH and one HPS should run cooler than 2x HPS...

If getting more light to the plants is the main thing someone was trying to accomplish then 1000 watts is the only way to go. The reason is this if one 600 watt bulb is putting out 95,000 lumens then two 600 watt bulbs will put out only 190,000 compared to 240,000 when using 2 1000 watt bulbs. They both take the same amount of space and when using using the 1000 watters you will get an additional 50,000 lumens over using the 600 watters. Believe me I found out the hard way and bought 2 600 watters which is also way more expensive. This is a perfect example of how real world application can be different then what the numbers on paper would seem to indicate............

 

[SirGrowAlot]

If getting more light to the plants is the main thing someone was trying to accomplish then 1000 watts is the only way to go. The reason is this if one 600 watt bulb is putting out 95,000 lumens then two 600 watt bulbs will put out only 190,000 compared to 240,000 when using 2 1000 watt bulbs. They both take the same amount of space and when using using the 1000 watters you will get an additional 50,000 lumens over using the 600 watters. Believe me I found out the hard way and bought 2 600 watters which is also way more expensive. This is a perfect example of how real world application can be different then what the numbers on paper would seem to indicate............

Yeah I see what you are saying Goshawk. BUt i already have a 600watt. And the thing was either get one 1000watter and use it by itself or get one more 600watter (then have two 600watters) and use them together. The space is only a 4x4. Two 1000watters would have temps krazy high.. But thanks for the input tho. I see what you are saying about two 1000watts being better than two 600watts.

 

[SirGrowAlot]

What is the best light to use for trying to get seeds to sprout after they have been germinated? I have read that daylight CFL's are better. But i figured that a MH would do better ( of course it would have to be set higher up).
What do you all think?