Need help with Cooling T5HO

Chrisss · Jan 5, 2016

I've been playing around with fan placement for a few weeks now on trying to figure out best fan placement for my DIY 4x54w T5Ho.

I have read up somewhere that you want to cool the "cool spot of the end cap" however I'm running waterproof end cap which do no have vent for air to come through. So I decided to go with the setup I have now. But I feel like I'm losing too much par because the fans are too powerful and cooling down the lights to fast. So I had these spare fans (computer fans) which were going to be the primary cooling of my T5ho but I decided to go with the bigger fans. But since I go a par Meter I've seen par drops in places.

So the big question is, should I keep those big fans going or install the small fans. And where should I install them? Should I put them at the ends and blowing air down at the end of the Endcaps or should I have them running across the lights like I do now??

Thanks!

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saltyfilmfolks · Jan 5, 2016

How much drop in par? thats weird.
in general lighting fixtures, smooth even cooling is best.
if your set up is open, dont worry about it. its already cooling the best it can and is designed for those temps. So the fixture is fine.
If your doing it to control the heat into the tank, get an acrylic cover for the lamps. or cooling fans into the tank on a temp sensor is best.

be careful chasing par or any meter reading. esp if its the first time you've done so. you can end up chasing your tail.
example, how much voltage is in your house outlet. wanna bet? watch what happens over a 24hr period with a recorder.

Chrisss · Jan 5, 2016

saltyfilmfolks said:
How much drop in par? thats weird.
in general lighting fixtures, smooth even cooling is best.
if your set up is open, dont worry about it. its already cooling the best it can and is designed for those temps. So the fixture is fine.
If your doing it to control the heat into the tank, get an acrylic cover for the lamps. or cooling fans into the tank on a temp sensor is best.

be careful chasing par or any meter reading. esp if its the first time you've done so. you can end up chasing your tail.
example, how much voltage is in your house outlet. wanna bet? watch what happens over a 24hr period with a recorder.

For example the par right above the water is 350 on both ends with a max of 620 in the middle. I just wanted to make sure my lights are being cooled enough so they last 9+ months and I'm not changing them every 6 months due to not cooled properly.

And I see what you mean, I just don't want to be having to change bulbs for no reason or losing out on par. I mean I can just keep lowering the lights that is not a problem, just wanted to make sure my lights were correctly working I guess. First T5ho Retofit setup so still playing around with it.

Chrisss · Jan 5, 2016

And Yes my setup is open, the heat it gives off doesn't really do anything to them temperature in the tank so the main reason for the fans were to cool the lights. @saltyfilmfolks

saltyfilmfolks · Jan 5, 2016

sigh. Par.
par is variable with the location of the sensor. a blue wall or white wall (or shirt or shadow of hand) can change the reading.
its different than intensity. intensity should be even across the fixture mostly except the ends.
Par really should be read in the tank. then averaged.
Check out Melevs reefs. He has a GREAT write up and walkthrough on measurements.

and yea out of the fixture they should last a lot longer than that. its designed to be in a hot little box.
If you want an average to watch. Take the same reading from the same exact place. and youll more accurately gauge the change over the course of weeks or months.

gus6464 · Jan 5, 2016

T5HO bulbs are most efficient at ~35C. Best way to figure out what you are running is to get an infrared thermometer at home depot and measure the bulb temp. If the bulb is running at around that temp then don't worry about cooling it.

Chrisss · Jan 5, 2016

saltyfilmfolks said:
sigh. Par.
par is variable with the location of the sensor. a blue wall or white wall (or shirt or shadow of hand) can change the reading.
its different than intensity. intensity should be even across the fixture mostly except the ends.

Par really should be read in the tank. then averaged.
Check out Melevs reefs. He has a GREAT write up and walkthrough on measurements.

and yea out of the fixture they should last a lot longer than that. its designed to be in a hot little box.
If you want an average to watch. Take the same reading from the same exact place. and youll more accurately gauge the change over the course of weeks or months.

Good points. But even in the water the par varrys like a few inches away same height the light drops like 50 to 100 par. So that's why it seems weird to me and thought I was cooling it wrong. But I'm just using it to see like the range not exactly its like a good estiment. Never ran it without fans on it so I'll test it out tomorrow

I will look into meleves write up when I get home. But that is a good idea to take the average every month or so. Thanks

Chrisss · Jan 5, 2016

gus6464 said:
T5HO bulbs are most efficient at ~35C. Best way to figure out what you are running is to get an infrared thermometer at home depot and measure the bulb temp. If the bulb is running at around that temp then don't worry about cooling it.

Ooo!! Never knew how cheap these things were that's why I never thought about it. I will definetly go to home depot or Lowes tomorrow and see how much I can pick up one!

Chrisss · Jan 6, 2016

gus6464 said:
T5HO bulbs are most efficient at ~35C. Best way to figure out what you are running is to get an infrared thermometer at home depot and measure the bulb temp. If the bulb is running at around that temp then don't worry about cooling it.

Bought one thanks for the idea this is exactly what I needed

gus6464 · Jan 6, 2016

Chrisss said:
Bought one thanks for the idea this is exactly what I needed

Nice. What temp your bulbs running at?

Chrisss · Jan 6, 2016

gus6464 said:
Nice. What temp your bulbs running at?

There are running at 96F to 101F or like 35.5C to 38.33C going to see what temp is tomorrow to make sure its accurate. It is a bit warm in my room right now

gus6464 · Jan 6, 2016

Chrisss said:
There are running at 96F to 101F or like 35.5C to 38.33C going to see what temp is tomorrow to make sure its accurate. It is a bit warm in my room right now

That's perfect. The reason why your bulbs didn't need extra cooling is because you do not have them contained under a splash guard. When BRS did the temp and PAR tests on the sunpower they found that if they took out the splash guard all they needed to do was run the fan at 3v to get it to the right temp. When splash guard was on it had to be run at 9v.

If your lights were inside a canopy you would need a fan to take the hot air contained within the canopy out and not blow it right at the bulbs. T5 bulbs are designed to run at their most efficient in open air in a climate controlled room.

Chrisss · Jan 6, 2016

gus6464 said:
That's perfect. The reason why your bulbs didn't need extra cooling is because you do not have them contained under a splash guard. When BRS did the temp and PAR tests on the sunpower they found that if they took out the splash guard all they needed to do was run the fan at 3v to get it to the right temp. When splash guard was on it had to be run at 9v.

If your lights were inside a canopy you would need a fan to take the hot air contained within the canopy out and not blow it right at the bulbs. T5 bulbs are designed to run at their most efficient in open air in a climate controlled room.

Thats the exact video I watched that made me trying to figure out different ways to cool my T5ho haha. And yeah I guess I was just overthinking that I need fans to cool it down.

Never really looked into cooling that much and those are probably the exact reasons why I don't have to cool. Guess I've been cooling down my lights for no reason for the last 8 months:mad:

gus6464 · Jan 6, 2016

Chrisss said:
Thats the exact video I watched that made me trying to figure out different ways to cool my T5ho haha. And yeah I guess I was just overthinking that I need fans to cool it down.

Never really looked into cooling that much and those are probably the exact reasons why I don't have to cool. Guess I've been cooling down my lights for no reason for the last 8 months:mad:

If anything your lights are going to be a bit stronger now as over cooling bulbs has a negative effect on par.