PAR readings T5

[cubbyman60]

I was fortunate to borrow a friend's Apogee PAR meter and take some readings on my tank. My tank is a 125 gallon (6 feet) with two 36 inch 6 bulb old Tek fixtures about 10 inches from the waterline. My bulbs are Coralife bulbs that are about 6 months old. I currently run 5/6 channels with a mix of white and blue bulbs. They were not purchased by me so I will only call them "white" and "blue.

My readings were as follows:
At the bulb (out of the water): about 500 for white bulbs and 350 for blue bulbs.
At the top 6 inches of the tank: about 120.
Half way down: 60-70.
Sandbed: about 30.

Now my questions:
1) These readings seem like a drastic PAR drop, especially with only 30 at the sandbed. Is this to be expected. Or, could it be attributed old lights and a poor fixture.
2) If I change the bulbs to ATI bulbs, will I expect a higher PAR reading.
3) If I change, specifically, to ATI Blue plus, will I get similar readings with a correspondingly increased PUR due to the usable wavelength I don't get from the "white" bulbs.
4) Are these PAR levels too low to grow coral? I don't have great coral growth overall except for Soft corals. Could the low PAR readings be partially attributing to this? I compared the PAR to the setups at my LFS who has great coral: and he is mostly running 50-100 for Soft corals, zoas, and LPS. He was around 200 for SPS. However, he runs a distinctly blue spectrum from LEDS, which could theoretically produce a lower PAR value and a higher PUR due to the spectrum.

I know that's a lot, but I found it interesting to have some more firm data regarding the output of the lights. Thanks for any input.

 

[drummerboyevil]

Get a 60" ATI 6 bulb and ATI bulbs. I run a 48" on my 60" 150 and I can easily get 250 at the sand if I want to


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[Ron Reefman]

1) These readings seem like a drastic PAR drop, especially with only 30 at the sandbed. Is this to be expected. Or, could it be attributed old lights and a poor fixture.
The drop in PAR from water surface to the bottom of the tank is normal. The PAR levels are too low for good coral growth.

2) If I change the bulbs to ATI bulbs, will I expect a higher PAR reading.
I've never used my PAR meter on t5's, so I can't say for sure.

3) If I change, specifically, to ATI Blue plus, will I get similar readings with a correspondingly increased PUR due to the usable wavelength I don't get from the "white" bulbs.
It works that way with leds, I'd assume the same thing should work with t5's.

4) Are these PAR levels too low to grow coral? Not too low for some very easy corals, but yes, generally way too low. I don't have great coral growth overall except for Soft corals. Could the low PAR readings be partially attributing to this? Absolutely! I compared the PAR to the setups at my LFS who has great coral: and he is mostly running 50-100 for Soft corals, zoas, and LPS. He was around 200 for SPS. However, he runs a distinctly blue spectrum from LEDS, which could theoretically produce a lower PAR value and a higher PUR due to the spectrum. PAR of 100 or more is just enough for most lps and 150 to 200 is enough for most sps. Higher PAR is better, but those numbers will work IMHO. I run 150 to 200 PAR at the sand in my mostly sps tank. Light being more blue is probably better PUR for most corals. But every zooxanthellae, algae and plant has a different PUR requirement, so generalizing is probably not a good idea.

 

[oreo57]

A reference chart. Take the PAR, divide by 2 for NO vs HO.
Multiply by # of bulbs.. Possibly then subtract about 20%

120PAr @16"..
Say 5 tubes..20PAR per tube approx..
According to the above chart (all all the assumptions) 27PAR is "expected"....

Assuming your effective total depth, light to sandbed is 32"..12.5PAR-25PAR..

On paper your readings seem fairly expected..
There is a LOT of assumptions and errors possible.. Including the meter being out of calibration .....

another one

Taking a few more generic readings and some interpretation..
At your depth and 6 bulbs NO t5 60PAR seems to be close to max average..

 

[2una]

Active cooling & good reflectors make a world of difference with T5's.
Red sea S650 stock T5 lighting (10x80W) uses same ballasts as whats in the Ati Sunpower unit - the Rsea don't use active cooling.
I doubled my par switching to a Ati Sunpower (8x80W) using the exact same tubes i pulled out of the rsea unit.

 

[cubbyman60]

These are all very informative and interesting responses. Thank you all for your time and input.

Now, I have to figure out a solution.

 

[rtparty]

1) Tek fixtures need to be cooled somehow. If you can get some small fans blowing across the TOP of the fixture, it will increase PAR. Do not cool the bulbs directly because overcooling can hurt PAR just as much as overheating.

2) Sorry to say but Coralife bulbs are junk. Switch to ATI or KZ bulbs. Just be careful when you do. You'll need to acclimate the tank slowly. Replace a couple bulbs a week for 3 weeks. I'd start with something like 3 Blue Plus, 1 Actinic, 1 Purple Plus and 1 Coral Plus. Put a blue and Actinic on your dusk/dawn channel.

 

[cubbyman60]

Again, thanks for the replies.

Based on the charts and the responses: could the simple fix be lowering the fixture? I personally don't think that would significantly help looking at the graphs.

Also, I don't have any quantifiable evidence how much PAR increase I would get from a bulb change alone. I know it would improve, but I don't know how much.

How high do you all typically mount fixtures like ATI?

Thank you.

 

[2una]

It wont hurt to lower it - will only help to raise the par some but do it slowly.
If the bulbs & or ballasts aren't getting cooled properly because of the way the unit does its cooling it probably would be minimal gain switching to higher spec tubes...
If the ballasts get too hot they back off the output so there's something to remember,
With that redsea t5 fixture of mine it had Aluminum heatsinks above the tubes - I rigged up some fans to blow over those heatsinks & got a 40 par increase.
But even with that i'm guessing the reflectors in it were junk after getting a double the par increase with the Ati unit.(with 2 LESS tubes too i might add)
+/- around 8-12 inch's off the water line is where you'll see most have them.

 

[rtparty]

Again, thanks for the replies.

Based on the charts and the responses: could the simple fix be lowering the fixture? I personally don't think that would significantly help looking at the graphs.

Also, I don't have any quantifiable evidence how much PAR increase I would get from a bulb change alone. I know it would improve, but I don't know how much.

How high do you all typically mount fixtures like ATI?

Thank you.

10" is quite high. Do your fixtures have acrylic shields on them? If so, lower them down an inch per week and get them closer to 4-6" from the tank. That will definitely increase PAR.

With lowering, change of tubes and cooling you could see nearly double the output in spots.

IIRC, Tek fixtures increase output nearly 30% from proper cooling alone. Not to mention your bulbs last 10-12 months this way. Non cooled T5s really should be replaced almost every 6-7 months.

ATI bulbs put out 10-20% more PAR than Giesemann bulbs and Gmann are considered a good bulb. It wouldn't surprise me one bit if ATI bulbs aren't putting double the PAR of Coralife tubes. I'd have to dig through some old threads and find Coralife readings. I remember testing Current USA bulbs and while the daylights had okay PAR, the actinic tubes they used were terrible. Coralife isn't much better if at all

 

[cubbyman60]

It wont hurt to lower it - will only help to raise the par some but do it slowly.
If the bulbs & or ballasts aren't getting cooled properly because of the way the unit does its cooling it probably would be minimal gain switching to higher spec tubes...
If the ballasts get too hot they back off the output so there's something to remember,
With that redsea t5 fixture of mine it had Aluminum heatsinks above the tubes - I rigged up some fans to blow over those heatsinks & got a 40 par increase.
But even with that i'm guessing the reflectors in it were junk after getting a double the par increase with the Ati unit.(with 2 LESS tubes too i might add)
+/- around 8-12 inch's off the water line is where you'll see most have them.

Those are impressive changes.

10" is quite high. Do your fixtures have acrylic shields on them? If so, lower them down an inch per week and get them closer to 4-6" from the tank. That will definitely increase PAR.

With lowering, change of tubes and cooling you could see nearly double the output in spots.

IIRC, Tek fixtures increase output nearly 30% from proper cooling alone. Not to mention your bulbs last 10-12 months this way. Non cooled T5s really should be replaced almost every 6-7 months.

ATI bulbs put out 10-20% more PAR than Giesemann bulbs and Gmann are considered a good bulb. It wouldn't surprise me one bit if ATI bulbs aren't putting double the PAR of Coralife tubes. I'd have to dig through some old threads and find Coralife readings. I remember testing Current USA bulbs and while the daylights had okay PAR, the actinic tubes they used were terrible. Coralife isn't much better if at all

I do have an acrylic shied on the fixture. Can I just take it off? It will be difficult to cool the tubes for aesthetics. I have the lights in my living room and would like to avoid the extra cords and mechanics. (I know, being difficult)

Thank you.

 

[ksc]

ATI bulbs aren't that good. You can gain a significant amount of par by lowering the fixture as low as feasible. Here's some par numbers from the different t5 makers. On the last page there are some readings after lowering the fixture from 11" to 5".

http://www.reefcentral.com/forums/showthread.php?t=918935

 

[gus6464]

There is quite a bit of wrong information in this thread.

For starters T5 ballasts don't back up on the output when they get hot. All modern electronic ballasts are designed to run in an sealed environment.

Active cooling has more to do on fixture design than a requirement. Why do Ati units have fans? Because of the splash guard. T5 bulb output is dependant on the ambient temp surrounding the bulb. Running to hot and too cold kills the output. Because of the splash guard the unit has to vent the buildup of hot ambient air surrounding the bulb somehow and that's where fans come in.

T5 has an optimal ambient temp of 35C. This means that if the surface area surrounding the bulb is kept at 35C then bulb out is maximized. In an open air fixture without a splash guard in a temperature controlled room fans and not needed and will actually hurt the output as the bulbs will be too cool.

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[rtparty]

There is quite a bit of wrong information in this thread.

For starters T5 ballasts don't back up on the output when they get hot. All modern electronic ballasts are designed to run in an sealed environment.

Active cooling has more to do on fixture design than a requirement. Why do Ati units have fans? Because of the splash guard. T5 bulb output is dependant on the ambient temp surrounding the bulb. Running to hot and too cold kills the output. Because of the splash guard the unit has to vent the buildup of hot ambient air surrounding the bulb somehow and that's where fans come in.

T5 has an optimal ambient temp of 35C. This means that if the surface area surrounding the bulb is kept at 35C then bulb out is maximized. In an open air fixture without a splash guard in a temperature controlled room fans and not needed and will actually hurt the output as the bulbs will be too cool.

Sent from my Nexus 6P using Tapatalk

T5 ballasts will cut output if they recognize the internal pressure of the bulbs is too high. It's to protect everything. I've talked to more than one company about this exact thing. If the ballasts aren't monitoring that, they aren't true T5HO ballasts. Admittedly, I have no idea how hot the bulbs have to get before they go into "protection" mode.

When I ran a tank in my basement for months the ambient air temp was 64°F and the bulbs still needed to be actively cooled. I don't remember which thread I posted all my findings in. It was 4 or 5 years ago.

 

[cubbyman60]

ATI bulbs aren't that good. You can gain a significant amount of par by lowering the fixture as low as feasible. Here's some par numbers from the different t5 makers. On the last page there are some readings after lowering the fixture from 11" to 5".

I rechecked my mount. Can't lower it unfortunately.

http://www.reefcentral.com/forums/showthread.php?t=918935

There is quite a bit of wrong information in this thread.

For starters T5 ballasts don't back up on the output when they get hot. All modern electronic ballasts are designed to run in an sealed environment.

Active cooling has more to do on fixture design than a requirement. Why do Ati units have fans? Because of the splash guard. T5 bulb output is dependant on the ambient temp surrounding the bulb. Running to hot and too cold kills the output. Because of the splash guard the unit has to vent the buildup of hot ambient air surrounding the bulb somehow and that's where fans come in.

T5 has an optimal ambient temp of 35C. This means that if the surface area surrounding the bulb is kept at 35C then bulb out is maximized. In an open air fixture without a splash guard in a temperature controlled room fans and not needed and will actually hurt the output as the bulbs will be too cool.

Sent from my Nexus 6P using Tapatalk

T5 ballasts will cut output if they recognize the internal pressure of the bulbs is too high. It's to protect everything. I've talked to more than one company about this exact thing. If the ballasts aren't monitoring that, they aren't true T5HO ballasts. Admittedly, I have no idea how hot the bulbs have to get before they go into "protection" mode.

When I ran a tank in my basement for months the ambient air temp was 64°F and the bulbs still needed to be actively cooled. I don't remember which thread I posted all my findings in. It was 4 or 5 years ago.

Should I remove the splash guard over the lights as a first move? Eventually, I'm going to have to start introducing more light whether it's with this fixture or an alternative option. Removing the splash guard theoretically will increase PAR and possibly increase the light output by improving passive cooling. Right?

Thank you.

 

[rtparty]

Should I remove the splash guard over the lights as a first move? Eventually, I'm going to have to start introducing more light whether it's with this fixture or an alternative option. Removing the splash guard theoretically will increase PAR and possibly increase the light output by improving passive cooling. Right?

Thank you.

Yes. Remove the splash guard if you can. If you have crazy fish that will splash the fixtures pretty bad, it might be better to leave it on and still lower the fixtures

 

[cubbyman60]

The risk of removing the guard being the obvious- splash burning out the fixture?

Thank you.

 

[rtparty]

The risk of removing the guard being the obvious- splash burning out the fixture?

Thank you.

That can happen. What I worry more about is the hot bulbs possibly cracking when cooler water hits them. It's a lot of work to take them down and constantly clean off the bulbs and reflectors when you have splashers as well

 

[drummerboyevil]

ATI bulbs aren't that good. [/url]

LOL... what?