how many lights on a 4*8 tray

so i have a 4 * 8 tray for a hydroponic grow and 2 raptors, 1000w, but someone told me that it would be better to put 3 1000w lights with smaller hoods instead of the 2 1000w raptors because the light is more intense. does anybody have any ideas? or is there anybody that has done it? i was gonna try it next time dunno yet though thanks.

3k over a 4x8 is alot of heat. Its possible and youll get donkey colas IF you can control the heat. Id stick with 2k in raptors, proven method

No doubt 3k is going to be better.Like mentioned ,heat and electric cost need to play into your desition. I know people that run 3 600's instead of 2x1000's and they swear by it. 2x1000 on a 4x8 puts you at 62.5 watts per sq ft. Thats pretty optimal if you ask me. When you are running a large hood like a raptor you typicly can run the lights lower. No need to have them in the sky to cover a the canopy.

Im running raptors right now and I definitely say stick with the 2 for the reasons stated above.

2-1ks or 3-600's do a 4x8 nicely

how do you like the coverage of the raptors on the 4x8 i run 3 600s in radiant 6" hoods and i am thinking about switching to raptors or xxxl hoods and 1000s

covarage is really good they dont have to be far at all to cover entire tray. anyone else have any input?

Go for 2 in the large hoods much better

I run High Tech Garden supplys version of the raptor,same type huge hood sized at 28" X 36" & they call it The Big Kahuna.

I run 8 seperate 4ft x 8ft tables,before i set up the big tables i was running 4ft x 4ft tables with a single 1,000 watt with a Big Kahune hood so i allready had some 1,000 watters,when i set up the big tables 6 of the 4ft x 8ft tables got set up with new 600 watters & new Big Kahuna hoods,the other 2 got set up with 2 1,000 watt lights with Big Kahuna hoods.

All the tables were set up 1 week apart for obvious harvest reasons,it didnt take long comparing the difference between the tables for me to replace the dual 1,000 watters with 3 600 watters,the 600,s flat out smoke the bigger lights.

When you set up the hood if you set it up with the short sides of the hood where they are on the long side of the table with the air intake/exhaust ports facing the long side of the table it gives the best coverage.

With all 3 hoods set up this way there will be a 2" gap inbetween hoods the full length of the table,at the end of the table if you hang a string from the hood you can see the side of the hoods on each end hang perfectly with the end of the table,every last ince of the table is covered by a reflector aside from the gaps between lights which are 2" gaps,so a total of 4" of the table isnt covered by the reflector.

This configuration smokes the dual 1,000's in every way because every square inch of the table is under the reflector,also if you have good air flow you can let the glass ride the canopy.

On my tables approx 25% of the plants have some touching the glass with no burn,the plants are roughly 3ft tall from the top of the net pot.

Before i rushed out & ordered more lights & shit i did my homework,i checked deep penetration on both the 1,000 & the 600's with my light meter,at canopy both lights were close but the smaller lights had a small advantage because they can be placed so close with no light loss,every inch deeper into the canopy i measured the 600 gained advantage over the larger 1,000,by the time i was measuring down about 18 inches into the canopy the 600's were clearly giving much better penetration,which again i atttibute to being able to place the smaller lights much closer,the 1,000 watters were kept at roughly 10" away from the canopy,any closer & plants fried.

Its harder to cool all 3 lights running them with the intake & exhausts ports being on the short side of the table instead of all 3 lights in a straight line but light coverage is so much better,if you put 3 raptors in a line where the intake ports are inside the table making venting a straight shot coverage is at a loss,both ends of the table have hood over hanging the table which is wasted light,this is why you had people tell you to run 3 smaller hoods.

I had the same problem & thats why i flipped the hoods the other direction & in the process i got the best light coverage possible,in order to properly vent the lights set up with all the turns in the pipe you will need to use 2 6" centrifugal fans in a push pull configuration,one fan sucking hot air out of the last light in the run & one fan blowing cool air into the 1st light into the run,set up like this the glass is cool where you wont burn leaves touching the glass.

If you have the extra cash for a 3rd light & an extra fan using 3 of the 600's is a way better set up & your 1st harvest will make up the extra cash spent because you get very little popcorn because penetration is better & the ENTIRE TABLE is basicaly covered by one big ass hood with 3 bulbs.

I have about the same square footage, 7' round is 35 square feet.
I use 4000 watts over the plants. All of the same reasons as posted by panhead but I use 10 x 400 watts in 5 separate spectrums and have them distanced to overlap on the canopy.
Every single square inch is covered with the maximum light, and that works very well.

and because I am a math person

1800 watts HPS at 140 lumens/watt = 25,200 lumen at glass.
4000 watts HID at 93 lumens/watt = 37,200 lumen/18" distance = 24,801 lumen on plants.

Twice the wattage needs more cooling or more distance, penetration is tremendous with that many lights.

A high ceiling is necessary, light reaches across the room for side lighting.

Electric cost more than doubles, custom spectrum gives early harvest.

HPS is less expensive, HID has colors.

Choices, choices. Panhead chose one, I chose the other, he is happy, I am happy. Must be more than one way to grow.

Mypoopcanfly: get what you feel in your gut you will like, the pot will grow and you will be happy. You like to balance input, my input is, more sources of light are better, big or small, more directions win. Good luck with the final choice.