Enclosed aircooled lights?
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Scooterman
Well-known member
Hey cracker, I'm working on that with my tank very soon! I have an 18" tall hood, 32" wide & 4' 6" long, so I have room to do things, that there is important. I'm slacking on my latest pics but I have a 7" fan that blows across the water line. I tried blowing air on the reflectors but really hasn't helped much, so I put it across the water surface. I just recently purchased two 120v ac fans, 4 1/2" each. I will try to cut out the holes this weekend & mount them, I will have them both sucking air out the top of the hood, I need to try & get the most out of them & locate them to get maximum suction. I also have a very large 12" fan in the sump area, this blows air completely across the 6 foot sump area & out the side. I do have a chiller & will need it but I'm designing the airflow to run as much fan power as I can, save on electrical power. If you give me a little time, I'll post some pics as I do the upgrades. The thread is under my name in the members showcase forums.
Krish
RF STAFF
This is the lighting I had on my old 75gal using a dual PFO 250w PFO retro kit with 20K XM bulbs. I used 5 fans (3 sucking air out of the top of the canopy and 2 blowing in cool air across the top of the water which you can see on either side). I simply drilled holes in the canopy at each fan location and put stainless steel grills over them to hide everything and it worked out great! One thing you have to be sure not to do is have the fan blow directly on the bulb as it will change the spectrum of the bulb as well as I've heard "may" kill the life of the bulb. 
Scooterman
Well-known member
I forgot how nice those came out Krish, yup, nice!
Krish
RF STAFF
LOL!! Thanks Scooty. I forgot how nice it is to have a tank! Soon time for a new project
Hey Scooterman, Krish Sorry the only pic I have is in my head. My dimensions will be close to yours Scooterman. Not as wide with three 250watt fixtures very much like yours Krish & hung from the ceiling. I want to install glass along the bottom & seal it somewhat, mount an inline fan at one end & blast air out the other end. It will all be hidden. Just kicking the idea around..
Design change! Talked with a friend who has a friend with some old fixtures for sale. Gave him a call.
He said he had a number of these 50$ a piece.
All I had to do was wire up the chord from a 250 mh I have.
This one is on loan with option to buy. It's 22 by 23 by 8" with a tempered glass pane. I hope these will fit my needs. Funny how "sometimes" things just work out. I got just a little info on how some types of glass will filter out light & such.
Krish, I just took a closer look at your hood came out real nice!
He said he had a number of these 50$ a piece.
This one is on loan with option to buy. It's 22 by 23 by 8" with a tempered glass pane. I hope these will fit my needs. Funny how "sometimes" things just work out. I got just a little info on how some types of glass will filter out light & such.
Krish, I just took a closer look at your hood came out real nice!
Last edited:
Krish
RF STAFF
Thanks!!!
Pic doesn't show the intensity very well but you can see the spread fairly well I have just two small dark triangles in each end. All I need is a couple smaller lights for the ends. I know near to nothing about smaller HO fixtures Any suggestions?
Scooterman
Well-known member
I think you could fit some T5 H.O. on an IceCap ballast, whatever else you need, from 24" to 72" I think. That would cover the rest of your tank, add color supplementation also, just be sure to get individual reflectors & they will help out greatly.
Hey guys,
Great questions and answers. Here is the results of some research i have done for this hobby and for my industry.
To maximize your cooling for air cooled fixtures here is what I found to be the most effective:
Saltwater tanks:
Fan blowing accross water column, the fan should push fresh cool air IN to the hood, preferrably from multiple points. Cool air should cross first be in touch with what you want cooled. Vent points should be from the hottest area (on top of the hood).
Electronics.
Fresh cool (and dry) air should be blown across electronics, then cross hot items and vent to an area that will not damage items outside the vent.
How this works: If you push air into an enclosed space... the air will vent out of the point(s) of least resistance. If a fan pushes 10 CFM then 10 CFM of cool air will enter the hood... 10 CFM of air of varying temperature will vent out of every point in the hood.
Push the air across what you want to cool 1st. If you want to cool the water, vent across the water... if you want to cool the light... blow the air across the light.
If you choose to have a fan PULL air. the following will most likely occure.
A fan that runs 10CFM of air pulling from a vent... must pull from a restricted place. Most likely it will cavitate and produce far less than it's optimum place. Also, the air is HOT in the hood... AND is very moist. Heat and moisture is not good for electronics.
My experience: I have put fans pulling in my hood first (I mounted them wrong and didn't pay attention). They burned out within 1 year. My tank maintained 81 degrees in the water. When I replaced the fans... i paid attention to how i mounted them. My tank dropped to 79 deg and was more consistent. My fans ran 4 years before I dropped the hood and increased lights.
Sorry for the long ramble... i can give you industry examples and more studies I've done with air handling and current in enclosed environment. Also... the water evaporating from my tank had a PH level on 6.4 (that is slightly acidic.)
Thanks
Great questions and answers. Here is the results of some research i have done for this hobby and for my industry.
To maximize your cooling for air cooled fixtures here is what I found to be the most effective:
Saltwater tanks:
Fan blowing accross water column, the fan should push fresh cool air IN to the hood, preferrably from multiple points. Cool air should cross first be in touch with what you want cooled. Vent points should be from the hottest area (on top of the hood).
Electronics.
Fresh cool (and dry) air should be blown across electronics, then cross hot items and vent to an area that will not damage items outside the vent.
How this works: If you push air into an enclosed space... the air will vent out of the point(s) of least resistance. If a fan pushes 10 CFM then 10 CFM of cool air will enter the hood... 10 CFM of air of varying temperature will vent out of every point in the hood.
Push the air across what you want to cool 1st. If you want to cool the water, vent across the water... if you want to cool the light... blow the air across the light.
If you choose to have a fan PULL air. the following will most likely occure.
A fan that runs 10CFM of air pulling from a vent... must pull from a restricted place. Most likely it will cavitate and produce far less than it's optimum place. Also, the air is HOT in the hood... AND is very moist. Heat and moisture is not good for electronics.
My experience: I have put fans pulling in my hood first (I mounted them wrong and didn't pay attention). They burned out within 1 year. My tank maintained 81 degrees in the water. When I replaced the fans... i paid attention to how i mounted them. My tank dropped to 79 deg and was more consistent. My fans ran 4 years before I dropped the hood and increased lights.
Sorry for the long ramble... i can give you industry examples and more studies I've done with air handling and current in enclosed environment. Also... the water evaporating from my tank had a PH level on 6.4 (that is slightly acidic.)
Thanks
All good info! If your trying to vent a light where airflow will be restricted like the hood pictured above You need a Squirel cage type fan. In very Simple terms,These "blowers" produce pressure much like a water pump where as a flat blade type fan does not.
I was looking into these hoods I have, they are designed for horticultural use. I was amazed at the lengths those guys go to to cool their lighting!
I was looking into these hoods I have, they are designed for horticultural use. I was amazed at the lengths those guys go to to cool their lighting!
Scooterman
Well-known member
If you push air into an enclosed space & you get the same out as it goes in, you also have to consider that blowing cool air in could blow cool air out if you don't have vents in the proper place, as we know heat rises so location of the vented air is just as important otherwise your pusing the some of the same cool air out, this won't be efficient. There is a lot to it, also the reverse could be true, two fans pulling hot air from top of the hood (enclosed area) would suck some cooler air from gaps in the lower regions & suck some hot air out. Now as in krish's hood he does both, three fans pulling heat out from up top & on the sides fans blowing in cooler air from the room. Also across the water surface, we know this is very efficient in cooling water through evaporation. One other impact is room air, rooms are for the most part closed & you could recirculate heated air, or humid air, something else to consider.
Thanks!
Squirrel cage fans are really efficient, and designed to PULL air from enclosed spaces. Love em. But they are a little large for most people... and they can get a little loud when they get older.
Venting out the top is by far the best place for exhaust. Or, if your hood isn't air tight... which none are... forcing air in forces air to vent from many points. Not as efficient, but effective.
If you have the tools, try the following.
2 identical calibrate digital thermometers
2 calibrated humidity gauges
1 fog machine
several identical fans.
spare 20 gallon clear tupperware container.
Air flow test.
Consider the tupperware your hood.
1. Drill it where you want to place your fans, and drill where you want the exhaust.
2. Mount fans
3. Fill the container with fog. (I used one from our shop) You can also use a metal pie tin and burn mineral oil... please do so outside) Note the numer of seconds the machine ran to fill, or the # of oz. of oil burned.
4. Turn on the fans with the air pulling the air out... and time it.
Result. you will see air flow, currents, and "dead" spots where the fog circulates. I also noticed in my experiments that the fans created fast currents, but not even flows.
Test 2: Same thing, but mount the fans pushing air into the enclosed container. You can even tape over the big exaust points in the top that had fans... instead consider small holes/ports all along the top. This was best for me.
1. Fill the container with the same amount of fog. It should be the same visually.
2. Turn on the fans and time away!
Result. You should see that there will be an initial "poof" of exhausted fog, then it slows for a second... then fog will begin flowing from every point that isn't air tight. There will still be dead spots in the corners... but you should notice they are smaller in nature and prone to moving around (like small tornadoes that form... move... disolve... a new one forms (fresh air).
With either test... feel free to add more fog while the fans run. you'll see the dynamic air flow of both systems.
Running both IN and OUT is by far the most efficient... but I believe you will torch the fans that are sucking air out.
Test 2, PH.
Place a piece of celophane over part of your tank... place a weight on it so it forms an upside down pyramid.
Place a small cup under the point of the pyramid.
This will collect water as it evaporates.
Once you have enough... run fresh water tests on it.
I found the PH to be very low... stripped of salts and such that don't evaporate... this water is slightly acidic. (notice how fast things rust?)
That is the water you are pulling across your fan's brushes.
TEMP/Humidity test
Place 1 gauge (of each type) in your hood, and 2 feet from your hood.
measure air temp and humidity several times a day for 2 days.
Reverse your fan direction. wait 1 day. Test several times a day over 2 days.
Results: (i did this in the summer time)
Fans Pulling air out: My air temp and humidity in and out of the hood was constant during my "day" cycle of lights.
Fans Pushing air IN the hood: My air temp in the hood fluctuated as much as 6 degrees but was an average of 8 degrees cooler. My water temp dropped a couple degrees. humidity in the tank fluctuated slightly but was overall slightly higher. Outside air temp only fluctuated a degree or two. Humidity outside the tank rose slightly in the evening when the lights shut off and the air temp all around cooled.
Results. it was my opinion that the air in the tank was cooler due to more efficiency in the air handling. having direct air over the water cooled and evaporated more water. The air temp fluctuation was most likely due to the air vents from my HVAC blowing generally at the tank (cool air sucked in fast) and occasional air currents recirculating tank air.
Also... if you are worried about dust... most fans have room for a small sponge style filter... this will impact your efficiency a little... but not much.
Good luck.
For electronics... we cool our systems, racks, rooms, etc by focing in fresh cool air at the floor or the hottest items... and pull air from the cieling to the outside or to the air conditioner... but there is no humidity factor here.
Venting out the top is by far the best place for exhaust. Or, if your hood isn't air tight... which none are... forcing air in forces air to vent from many points. Not as efficient, but effective.
If you have the tools, try the following.
2 identical calibrate digital thermometers
2 calibrated humidity gauges
1 fog machine
several identical fans.
spare 20 gallon clear tupperware container.
Air flow test.
Consider the tupperware your hood.
1. Drill it where you want to place your fans, and drill where you want the exhaust.
2. Mount fans
3. Fill the container with fog. (I used one from our shop) You can also use a metal pie tin and burn mineral oil... please do so outside) Note the numer of seconds the machine ran to fill, or the # of oz. of oil burned.
4. Turn on the fans with the air pulling the air out... and time it.
Result. you will see air flow, currents, and "dead" spots where the fog circulates. I also noticed in my experiments that the fans created fast currents, but not even flows.
Test 2: Same thing, but mount the fans pushing air into the enclosed container. You can even tape over the big exaust points in the top that had fans... instead consider small holes/ports all along the top. This was best for me.
1. Fill the container with the same amount of fog. It should be the same visually.
2. Turn on the fans and time away!
Result. You should see that there will be an initial "poof" of exhausted fog, then it slows for a second... then fog will begin flowing from every point that isn't air tight. There will still be dead spots in the corners... but you should notice they are smaller in nature and prone to moving around (like small tornadoes that form... move... disolve... a new one forms (fresh air).
With either test... feel free to add more fog while the fans run. you'll see the dynamic air flow of both systems.
Running both IN and OUT is by far the most efficient... but I believe you will torch the fans that are sucking air out.
Test 2, PH.
Place a piece of celophane over part of your tank... place a weight on it so it forms an upside down pyramid.
Place a small cup under the point of the pyramid.
This will collect water as it evaporates.
Once you have enough... run fresh water tests on it.
I found the PH to be very low... stripped of salts and such that don't evaporate... this water is slightly acidic. (notice how fast things rust?)
That is the water you are pulling across your fan's brushes.
TEMP/Humidity test
Place 1 gauge (of each type) in your hood, and 2 feet from your hood.
measure air temp and humidity several times a day for 2 days.
Reverse your fan direction. wait 1 day. Test several times a day over 2 days.
Results: (i did this in the summer time)
Fans Pulling air out: My air temp and humidity in and out of the hood was constant during my "day" cycle of lights.
Fans Pushing air IN the hood: My air temp in the hood fluctuated as much as 6 degrees but was an average of 8 degrees cooler. My water temp dropped a couple degrees. humidity in the tank fluctuated slightly but was overall slightly higher. Outside air temp only fluctuated a degree or two. Humidity outside the tank rose slightly in the evening when the lights shut off and the air temp all around cooled.
Results. it was my opinion that the air in the tank was cooler due to more efficiency in the air handling. having direct air over the water cooled and evaporated more water. The air temp fluctuation was most likely due to the air vents from my HVAC blowing generally at the tank (cool air sucked in fast) and occasional air currents recirculating tank air.
Also... if you are worried about dust... most fans have room for a small sponge style filter... this will impact your efficiency a little... but not much.
Good luck.
For electronics... we cool our systems, racks, rooms, etc by focing in fresh cool air at the floor or the hottest items... and pull air from the cieling to the outside or to the air conditioner... but there is no humidity factor here.
Scooterman
Well-known member
RSD good information, seem like you have done you homework, when you get time maybe you can look at my hood & help me in placement of my two AC fans to help with cooling. I'm still undecided on where I should place them, also now you have me thinking maybe I should pump air inside rather than suck air out, we just mentioned how fans don't last, I realize that the air quality is crappy for them in that situation & we want stability but that large drop in temps If we could stabilize it might be nice if we don't burn out fans so much. My hood is open in the back & sides completely, so air movement should be easy If done right.
No Problem. Do you have pics?
Also, I have to be honest... what spurred most of my research wasn't this hobby, rather the best way to cool amp racks that are in the sun... and keep them clean on the inside. I am partner in a company that handles alot of the concerts, events, installs, etc. in the Pacific Northwest. So when I had to educate myself with tanks... I attacked it with the same meathods of testing.
Feel free to send me photo's through e-mail or here on the post. If you are open on the back and sides of the hood. This should be pretty simple to cool.
Currently I use two light fixtures that are enclosed... but have no hood on the tank. The manufaturer has fans pulling air out the top of the MH fixture... and 2 micro fans pushing air directly over the ballast... it also has vents on the side. I plan on adding 2 fans to those vents if it becomes too hot this summer.
My tank... I have 2 fans mounted 4" from the wall drawing cool air from behind/below the tank and blowing directly across the tank top (I have a glass lid with screened openings,) the screened openings draw air in, across the water, and then out again. I also have a 4" fan that blows air into my sump/fuge area to vent warm air out of the underside of the tank/stand. There is no vents in the stand... but when that fan comes on it pushes the doors open. I usually prop them open 1/4" on hot days.
all 3 fans are plugged into an outlet that is regulated by a thermostat that normally would be used to regulate attic fans. Then, when my air temp in the house (our new house doesn't have AC) reaches 75 deg all these fans come on.
Through last years heat wave (90+ deg) my tank stayed at 79.9 at night, and 80.2 during the heat of the day. The fans stayed on until the house fell below 73 deg... and didn't turn on till the house was at 75. The hottest my house hit was 82. Almost made me pay for AC. Oh yeah... I have 450watts MH and 768 watts PC and I don't have a chiller.
180 gallon tank, 40 gallon sump. Winter evaporation rate... 4 gallons/week. Summer evaporation rate (highest temp) 5 gallons/week.
Hopefully that helps define what the I face.
Also, I have to be honest... what spurred most of my research wasn't this hobby, rather the best way to cool amp racks that are in the sun... and keep them clean on the inside. I am partner in a company that handles alot of the concerts, events, installs, etc. in the Pacific Northwest. So when I had to educate myself with tanks... I attacked it with the same meathods of testing.
Feel free to send me photo's through e-mail or here on the post. If you are open on the back and sides of the hood. This should be pretty simple to cool.
Currently I use two light fixtures that are enclosed... but have no hood on the tank. The manufaturer has fans pulling air out the top of the MH fixture... and 2 micro fans pushing air directly over the ballast... it also has vents on the side. I plan on adding 2 fans to those vents if it becomes too hot this summer.
My tank... I have 2 fans mounted 4" from the wall drawing cool air from behind/below the tank and blowing directly across the tank top (I have a glass lid with screened openings,) the screened openings draw air in, across the water, and then out again. I also have a 4" fan that blows air into my sump/fuge area to vent warm air out of the underside of the tank/stand. There is no vents in the stand... but when that fan comes on it pushes the doors open. I usually prop them open 1/4" on hot days.
all 3 fans are plugged into an outlet that is regulated by a thermostat that normally would be used to regulate attic fans. Then, when my air temp in the house (our new house doesn't have AC) reaches 75 deg all these fans come on.
Through last years heat wave (90+ deg) my tank stayed at 79.9 at night, and 80.2 during the heat of the day. The fans stayed on until the house fell below 73 deg... and didn't turn on till the house was at 75. The hottest my house hit was 82. Almost made me pay for AC. Oh yeah... I have 450watts MH and 768 watts PC and I don't have a chiller.
180 gallon tank, 40 gallon sump. Winter evaporation rate... 4 gallons/week. Summer evaporation rate (highest temp) 5 gallons/week.
Hopefully that helps define what the I face.
DonW
R.I.P.
DonW
I've used a powerhead to stir things up, break up the sand, free detritus for filtering... like a mini storm. I've never thought about creating a hurricane.
I think that fan would cool most tanks. I do think it may be a little loud though. I'd have to turn the radio up ALOT.
I've used a powerhead to stir things up, break up the sand, free detritus for filtering... like a mini storm. I've never thought about creating a hurricane.
I think that fan would cool most tanks. I do think it may be a little loud though.
I'd have to turn the radio up ALOT.
