Good or Bad Deal on HPS CoolTube Setup?

[Guest]

Maryland Hydro - Complete HPS system

Wattage : 600 (+70)
Reflector : 20.0 Inch Cool Tube External Reflector 6 Inch Diameter (+89)
Bulb : Hortilux 600 (+33)
Digital Thermometer : NO

Total: $321.95.. To those who were born with the gift of bargain shopping, do you think this is a good deal? Anyone have experience with their systems? I wouldn't say I am strapped for cash, but I am always willing to save a few extra dollars Thanks in advance.

 

[Jnugg]

Yes.They seem to have te best deals on the net.If you want to save a few dollars then just get a standard 600 watt bulb rather than the Hortilux Bulb.

 

[Guest]

Lots of people swear by their Hortilux bulbs, thats the only reason I added it to the list. Im such a trendy whore =]

 

[Jnugg]

Don't get me wrong,Hortilux bulbs are sweet.Just saying if you want to save a few bucks you know but 33 bucks ain't that much if you wanna grow good weed!

How big is the area you plan on growing in?Means of exhuast and fresh air intake?

 

[Guest]

I have nothing yet, the plan is to build a simple box that is 3x5x4.5. 8000 btu window shaker vented right into it. As far as exhaust, heres a sill numerical picture.


Filter---cooltube(600w)---cooltube(600w)--------6'' inline fan

Its that simple =]

 

[Jnugg]

So Let me get this right.You're going to build a box that is 3' deep x 5' wide x 4.5' tall (15 square feet/67.5 cubic feet) and two 600 watt HPS (1200 watts total) or just one?

That would work as far as square footage but I don't like the height of your planned box.Try to make it atleast 6 or7' tall and maybe go with a 1000 watt HPS

 

[Guest]

two 600s.

why soo tall of a cab? I might go 5 maybe 5.5ft, anyways if Bushmaster stops the stretch like other users reported, I shouldn't have to worry about height restrictions

 

[bostrom155]

Is security an issue, i'm guessing not with an a/c pumping into the box. If it is though, everything (filter, fans, ect) will fit in a tall box.

Measure everything out, Pots -- Plants -- space -- Light -- Fan
example 12 + 24" 8-10" 9" ?
How high is it all together, and 24" for a plant is not very big, even if your growing low profile now, what about in a few months you want to try different growing styles, or different kinds of weed......gl

I'm in a C24, its 6 feet tall and everything is in thier.

Also go with 2 x 600 rather than 1 x 1000, only reason is because of the footprint....you will be good to go

 

[shiftfoot]

I think you'll b fine w/ the 2 600's but like others have said I'd go a bit higher if ya can.MD Hydro will upgrade ya to the plantastar bulb for free if ya call an place your order,they did for me.I don't feel that the Hortilux is worth 33 more than the PS myself.
You could always hide the filter on top of the box you build w/ another box of some sort.I found that black n white poly to b good for the inside of the box couse it's easy to clean and you can seal it off to light completely behind the doors and add one of the stickon zippers for access.Works great for me,no light leaks>good luck and keep us posted.Hey you could do a step by step tutorial of your box build,I'm sure it would be well received.Oh andd yes that's a great price.Peace,Shiftfoot

 

[Guest]

Is security an issue, i'm guessing not with an a/c pumping into the box. If it is though, everything (filter, fans, ect) will fit in a tall box.

security kind of is an issue...but its more like paranoia. The box is going to be sitting right in front of the a/c, so I really don't think someone would question it, or even notice that it for that matter =p Thanks for the advice bos I appreciate it ^^

I think you'll b fine w/ the 2 600's but like others have said I'd go a bit higher if ya can.MD Hydro will upgrade ya to the plantastar bulb for free if ya call an place your order,they did for me.I don't feel that the Hortilux is worth 33 more than the PS myself.
You could always hide the filter on top of the box you build w/ another box of some sort.I found that black n white poly to b good for the inside of the box couse it's easy to clean and you can seal it off to light completely behind the doors and add one of the stickon zippers for access.Works great for me,no light leaks>good luck and keep us posted.Hey you could do a step by step tutorial of your box build,I'm sure it would be well received.Oh andd yes that's a great price.Peace,Shiftfoot

Thanks shiftfoot, i'll ask about the plantastar when i get around to ordering ^^ As far as hiding the fan, I was planning on sticking the thing inside a rubber maid tub next to the box. If you walked into a room and saw a cabinet with rubber maid tubs surrounding it, would you think twice about it? Either way I plan on cluttering up the area around the box to draw attention away from it. About the growfaq, I would love to do one, but I think the price would scare many away. The 6'' fan, a complete hps cooltube setup with external 20'' reflector, and another cooltube without the hps, comes out to a total of $626...thats not including shipping. That alone would scare me off...

 

[shiftfoot]

Just detail the box build itself.You could use 1 light on a small rail mover and cover the area a bit cheaper.Although I've never heard of anyone doing a light mover in a box set up.

 

[Guest]

this whole thread nobody noticed he didnt mention which ballasts and how much they cost????????????


dex, which are ya usin? its the most expensive part, the rest of the stuff you mentioned sounds like its priced super!

i suggest ebay and a safe acct/addy for the best deals out there, don't buy bullshit no-name chinese import brands tho, make sure it's good reliable stuff. The old saying you get what you pay for is highly underrated

 

[Guest]

this whole thread nobody noticed he didnt mention which ballasts and how much they cost????????????


dex, which are ya usin? its the most expensive part, the rest of the stuff you mentioned sounds like its priced super!

i suggest ebay and a safe acct/addy for the best deals out there, don't buy bullshit no-name chinese import brands tho, make sure it's good reliable stuff. The old saying you get what you pay for is highly underrated

http://shop.store.yahoo.com/californiahydro/ht-high-pressure-sodium.html

Is it shitty?

 

[shiftfoot]

Yeah,the ballast is included in that price w/ a 6 year warrantee.Not to shabby.On a side note they have also been selling digital ballasts on ebay,the lumitek and future brite ones and folks have been getting some good deals.Someone just picked up a little 400 w digital for 153 new,seems pretty good to me.Might be worth checking out.Later,shiftfoot

 

[Guest]

When digital ballasts become the "new standard" in horticulture, i'll purchase one. Until then, i'll stick to what I know works. A few more question though. Is a 449cfm 6'' Vortex enough to cool two 600w kooltubes? Or get the 8''? How does everyone control their humidity inside their cabs? What do you do when its too low? Thanks.

 

[Jnugg]

Hey Dez,check this out.



ntroduction:

Every serious growing box needs cooling. Most of us use air cooling because it is cheap and very effective. The following steps are used to design a simple fan-cooled box.

This method does not cover active cooling with air conditioning systems or 'CoolTube' designs. It is for grow chambers where the walls are approximately equal to the light pattern, totally enclosed for airflow control, and do not have large radiant heat into or out of the box. Your mileage may vary some for these reasons.

I also picked sane defaults for growing conditions. The formulas diverge if you get too far out of plant growing range. You should be very safe if you are within about 40 to 150 degrees F and 20% to 90% humidity ranges (those are just guesses). Atmospheric pressure was picked as sea level and doesn't really affect anything until about 5,000 or 8,000 feet depending on how accurate you want to get. If extreme conditions apply to you, there may be other FAQ entries with the entire full blown set of pressure/temp/airflow/humidity parameters.



Design

1) Start at the beginning and design this right! Before you ever buy or cut anything for your new project, determine the highest temp (in F) your intake air will ever be when lights run. Get a thermometer and measure it to make sure you have a good value. Call this T(inlet)

2) Use these formulas to determine difference in temp you can tolerate. 81F (27F) is about the optimal for growing, 86F/30C on the higher end.

Tdiff = 81F - T(inlet) (English)
Tdiff = 27C - T(inlet) (Metric)

3) Add up wattage for all power in your box. Lights, pumps, heaters, humidifier, radio, coffee pot, whatever. Add it all up and call it Watts. This will make your number worst-case and therefore a conservative value.

4) Compute the absolute minimum fan power you will need using the following formulas. This is the minimum fan rating you must have to achieve your temperature goals. You will have to increase fan power to compensate for duct constrictions, small inlets, carbon scrubbers, screens, or other items that block airflow.

CFM = 3.16 x Watts / Tdiff (English)
CMH = 2.98 x Watts / Tdiff (Metric)

The formulas are almost identical, due to the counteracting effects of converting airflow from CFM to CMH, and converting temp from Fahrenheit to Centigrade.

formulas can be found on this web page:

(This web site also lists the above formula and uses a constant of 3.16 as shown above)

5) If you have more than one fan, they should be mounted side-by-side rather than inline if you want to add their different CFM ratings.

For inline fans, use the lowest airflow rating of all fans in the path. A fan on the inlet and a fan on the exhaust of the box are considered inline fans. Fans inside the box should not be counted for airflow but must be included in wattage. A standard computer fan is normally right around 30 CFM (50 CMH).

The two lookup charts solve this equation for common lights. Make sure you get the proper one (English or metric). For those of you who are wondering if you did this right, here are a few numbers in English units :


Watts CFM Tdiff
70 30 7.4
150 30 15.8
150 60 7.9
150 130 3.6
250 130 6.1
250 265 3.0
250 400 2.0
400 130 9.7
400 265 4.8
400 400 2.7
600 265 7.2
600 465 4.1
1000 30 105.3
1000 265 11.9
1000 465 6.8

Note: a 30cfm computer fan is trying to cool a 1000w HID bulb, in the 3rd from the last row, as an extreme example

If you are adding any carbon scrubbers or extensive ductwork, this is where you add to the fan size to account for air pressure losses. You have to move this many CFM, or the numbers don't come out right. The deciding factor for these items depends on your exact configuration and is beyond this discussion.

6) When your box is built, buy a thermometer and measure the air blowing out of the box (temp probe or thermometer should be in the air stream just after the fan, outside of the box enclosure) and the temp of the air entering the box (again, from outside the box perimeter). Make sure there is no direct light shining on the thermometers to ruin the measurement. DON'T MEASURE THE TEMP INSIDE THE BOX YET!!!! It's best to do this with 2 thermometers or a single thermometer with a remote probe. Cheap thermometers don't work well because they aren't very accurate. If you only have cheap thermometers, use the same one for all measurements to avoid accuracy issues.

7) Subtract your measured inlet from measured outlet temp. Compare to Tdiff from above. Is your measured difference as good or better than your estimated from step 2? If not, go find out why. Your problems are probably:

A. Heat source you didn't account for (the ballast?)
B. Your fan is overrated
C. You have blocked airflow
D. Your temperature measurement was inaccurate
E. Air leaks into the box (especially around the fan!) that ruin efficiency.

8) Once you get your measured temp difference equal to step 2, measure temps inside the box. Don't let the light shine right on the sensor, it will give faulty readings!! Use a light shield made from a tin can or something. If temps inside the box are higher than your exhaust temp at a reasonable distance from the bulb, you have air circulation problems inside the box. Get some kind of fan to stir up the air in there or look for airflow paths that allow air to travel from inlet to exhaust without spending any time in the box.

9) Always monitor the temperature difference between inlet and outlet temps every time you water the plants. If it varies much more than a degree or two, find out why. I use digital indoor/outdoor thermometer. It tracks high and low for both locations, outdoor probe is on a long wire, $14 at Kmart. No part of the thermometer is inside the box, just in the measuring air blowing in and out from the outside.

Please note that conversion values have been slightly rounded off to make this easy. Using the metric and english formulas will yield slightly different answers if compared. The difference should be less than one percent and can be ignored.

You can use the two load graphs attached if you prefer to do calculations visually rather than using the formulas listed above. Find the line for your light wattage and ignore all others. Each axis is logarithmic, make sure you count along each axis properly. The formulas listed in step 4 were used to make the graphs.

Sidenotes:

You can measure your fan airflow very accurately if you use a standard trouble light with a 60 or 100 watt bulb in it. These are very good test loads for calibrating things.
Just put it in and work through the formulas using a good thermometer to determine airflow. If you doubt the accuracy of your bulb and are really anal about it, you can calibrate the bulb against your electric meter over several minutes. You could also stick in a different brand of bulb at the same wattage and compare results. I haven't tried this, but I would just trust the bulb until proven wrong.

Testing and measuring duct losses:

Ducting losses are hard (to measure) because they rely on knowing your duct material coefficients. You can measure the losses in the duct after it is built and running, if that would help. You could measure a test section to calibrate that material, then extrapolate. Here's how:

Take a known fan (or the fan you will be using) and blow it into a plenum that has a heat source and some of your sample duct mounted to it. To do this, you need a trouble-light or other low wattage known source and a cardboard box to put it in, then mount the fan on the box and stick the duct on the other side.

Calibrate the box by measuring temps without the ducting, then compute CFM. Add the duct, measure the new temp, compute the new CFM. The difference is duct loss. Basically, use temperature and wattage to measure airflow and compute duct loss.

If you have an existing room, just measure inlet and exhaust temps, add up the watts, and then compute effective airflow. I just did this for my box and it's pretty much dead on. I think it varies by about +/- 0.2 DegF for 150 watts and two computer fans.

Once you have the value for your ducts, you can estimate loss by adding up the length. We would have to come up with adjustment for going around corners.

I once saw a Mech Eng. book that had different shapes of pipe listed (Tee, 45 Deg bends, 4-way branches, Y-branches, etc) and then gave an equivalent length of straight ducting they add for flow resistance.

 

[Jnugg]

And this



What temperature will my growspace get and how much ventilation will I need?
Overheating is a common problem encountered by growers, especially in closet or 'box' setups. High temperatures cause whispy buds and is often a sign of inadequate ventilation, which brings a whole host of other problems.

Whether at the design stage or struggling with an existing problem, the following formula can be useful in assessing your situation. Its pretty basic in terms of heat transfer but from experience has proved to be pretty accurate for our purposes.

The formula is:

Q = V x P x C x dT

where:
Q = Amount of lighting (kW)
V = Volume of air being ventilated (m3/s)
P = Density of air (assume 1.2 kg/m3)
C = Specific heat capacity of air (assume 1.02 kJ/kgK)
dT = Temperature difference between ambient and growspace air in degC

You can use this to determine what the temperature rise in your space will be (dT), or given a desired temperature rise you can use it to work out how much ventilation you will require (V)

To get from CFM to m3/s divide the CFM by 2119.

Examples
Here are some examples of how you could use the formula in three different ways, each using the same basic figures for clarity.

What temperature am I likely to get in my growspace?
Assume: Lighting = 400W (0.4kW), ventilation = 240m3/hr (0.067m3/s) and temperature of air entering room = 21degC

Q = V x P x C x dT
=> dT = Q / (V x P x C)
=> dT = 0.4 / (0.067 x 1.2 x 1.02)
=> dT = 4.87, i.e. 21 + 5 = 26degC in growspace

How much ventilation am I likely to need?
Assume: Lighting = 400W (0.4kW), temperature of air entering room = 21degC and temperature of growspace to be no more that 26degC

Q = V x P x C x dT
=> V = Q / (P x C x dT)
=> V = 0.4 / (1.2 x 1.02 x (26-21))
=> V = 0.065 m3/s i.e. 240 m3/hr

What is the most lighting I can put into my growspace?
Assume: Ventilation = 240m3/hr (0.067m3/s), temperature of air entering room = 21degC, temperature of growspace to be no more that 26degC

Q = V x P x C x dT
Q = 0.067 x 1.2 x 1.02 x (26-21)
Q = 0.41 kW i.e. 400 W

 

[Jnugg]

When in doubt always go with a larger than needed fan,afterall you could always run it with a solid state speed controller so it runs quieter but still moves an assload of air!

 

[Guest]

wooooooooooooooooot!!!!!!! Thanks for the extra knowledge

 

[Jnugg]

No problem.But I feel for some reason that someone will be chiming in to scorn me for showing an ever so precious peice of knowledge........