par meter findings

[zygote2k]

I borrowed the PAR meter today and tested my light levels at various depths in my tank. Here's what I have:

Just the 2 32w PC bulbs

1" above the surface 052

1" below the surface 039

middle tank 024

bottom of tank 019

 

400w 14k SE and the PC's

 

1" above the surface 111

1" below 080

middle 047

bottom 037

 

@surface of the glass shield 475

 

My light is a PFO 400w MH w/ 2) 32w PC's in a hanging pendant. The distance from the glass shield to the surface of the water is 10"

Are these readings correct? What can I do to get more light to the corals? All my corals are growing though- so maybe I don't need to worry about the numbers so much?

I'll be testing 5 more tanks this week and I'll post the results.

[Sikryd]

What par meter are you using? Is it calibrated for sun or inside lighting? (I'd get technical, but it doesn't really matter - usually they are calibrated for one or the other)

Is it attached to a multimeter? What setting is it on?

 

Most likely those numbers need to be multiplied by something, most DIY meters are setup with some type of multiplyer since the value is off.

 

For example, my buddies is set so you have to multiply the screen reading on the multi-meter by 5x.

Edited August 22, 2009 by Sikryd

[Boret]

If it is the WAMAS one then those readings are way off. I get over 2000 (meter maxes out) a few inches from a SE 400w Radium 20k and about 200 at the bottom of the tank.

[zygote2k]

This is the PAR meter from JM.

It is an Apogee Model QMSS.

[Origami]

A long time ago, I borrowed the WAMAS light meter to measure the PAR from top to bottom of my Coralight Aqualight Pro-lit 90 gallon setup. The light setup used was their dual 150W HQI using 10KK bulbs run off of their magnetic ballast plus 2 each 96W actinic power compact fluorescent bulbs. The bulb height was 6" from the water surface and measurements were as follows: 840 at the surface; 472 @ 3" below the waterline; 314 @ 6"; 225 @ 12"; and 180 @ 18". Despite actually owning a PAR meter, I've never set it up to take readings on the new system. These readings were taken using the WAMAS PAR meter, which is an Apogee quantum meter registering PPFD (photosynthetic photon flux density) in units of micro-moles of photons per square meter per second (1 micro-mole of photons = 1 micro-Einstein).

 

Rob, I don't recall if the WAMAS meter has a low battery indicator, but that may be the issue. Do you still have it with you? If so, take it outside and get a reading. It's pretty cloudy here in Ashburn right now, but I'm getting a reading of 285 umol/m-s out on my back deck.

Edited August 22, 2009 by Origami2547

[zygote2k]

I took it outside just now and it's overcast here as well. The meter reads about 210 umol m-2 s-1.

[Origami]

Well, I can't tell if it's the battery or not, I guess. If you have a spare 9V battery lying around, you can try changing it out. The meter is pretty sensitive to the angle it's placed at. It's best to keep it level, so the sensor's pointed straight up. I suspect that you're already doing that, though.

 

The rate of fall-off in your numbers as you measure further and further down into your water column looks reasonable. What doesn't look reasonable is the PAR measurement that you're getting off the bulb. I'd focus either on the meter battery or on the lighting setup (bulb or ballast).

 

Do you have a kill-a-watt meter by any chance? If so, try putting it on your ballast and see what kind of power you're drawing when the MH is on. Also, is your reflector and bulb clean? Some bulbs, as their spectrum shifts to the blue end, put out lower PPFD per watt consumed, but your values just seem low.

[zygote2k]

new bulb less than 2 weeks old. clean reflector too.

I'm going to test David Beasleys' tank tomorrow and I'll be able to get a comparison. He has an AquaMedic 2x 250 plus 2)54w T5 fixture. I'll also test a tank that has a 400w 14k Hamilton fixture and a 175w 20k Hamilton fixture on Monday. On Tuesday, I'll do another tank with 2 400w 14k Hamiltons.

Thursday will be the 240 with 2) 400w PFO's and a 250w AquaMedic Starlight. Friday will be another setup like Davids. I'll measure the distance from the fixtures to the surfaces as well. If there are any factors that I am missing, LMK and I'll record them as well.

[ctenophore]

Based on your overcast outdoor report of 210, the meter is working correctly. I get about that on cloudy days. I think your light fixture is having issues. Does the bulb appear bright just by looking at it? You should be able to look directly at a light source giving off 111 umol. Is the glass shield clean?

 

I've not seen the WAMAS meter, but does it have the switch for sunlight vs. artificial light? My apogee has a big dial on the front with options for both.

[zygote2k]

The light is bright enough that it leaves an instant retina burn when you look at it. The glass is clean as a whistle and the reflector is clean too. The water is clear and looks like mercury on the surface. The meter doesn't have a dial for electric or sunlight.

[zygote2k]

I went outside today and the sun was bright and measured about 1100 on the meter. I measured David Beasley's light too. It is an Aqua Medic 2x250mh and 2x 54w T5 fixture that is 5" above the water surface.

1" above 1270

1" below 900

middle 500

bottom 335

 

Something is seriously wrong with my light or the bulbs. I'll change the bulbs back to the 10k and then the old unknown brand 14k's and see if there is anything noticeably different. If not, then I need to find a 400w PFO ballast. Anyone got an extra lying around?

[Sikryd]

I went outside today and the sun was bright and measured about 1100 on the meter. I measured David Beasley's light too. It is an Aqua Medic 2x250mh and 2x 54w T5 fixture that is 5" above the water surface.

1" above 1270

1" below 900

middle 500

bottom 335

 

Something is seriously wrong with my light or the bulbs. I'll change the bulbs back to the 10k and then the old unknown brand 14k's and see if there is anything noticeably different. If not, then I need to find a 400w PFO ballast. Anyone got an extra lying around?

 

Sounds like you are figuring it out. Its kind of nice to have a par meter handy sometimes to be able to test stuff like this, since you don't really know the amount of "energy" it is putting out the naked eye.

Good luck, hopefully it is something simple.

[zygote2k]

I bought this '400' watt fixture that I currently have and use with the low PAR readings. Is it possible that I really have a 250w ballast running a 400w bulb? There are no numbers on the PFO ballast anywhere that I can find. Can a 250 power a 400w bulb? Do ballasts start producing less power as they get older?

[zygote2k]

I changed bulbs from a new 14k to a new 10k and I get the same results. I think it's time for a new ballast. I'm going to buy the one that Leishman has for sale.

[Origami]

I bought this '400' watt fixture that I currently have and use with the low PAR readings. Is it possible that I really have a 250w ballast running a 400w bulb? There are no numbers on the PFO ballast anywhere that I can find. Can a 250 power a 400w bulb? Do ballasts start producing less power as they get older?

 

Rob, do you have a kill-a-watt meter? I have one you could borrow for a couple of days. It would allow you to get a power consumption reading off of that ballast as it drives your bulb.

[zygote2k]

Tom- I would like to borrow that meter and some instructions on how to use it. Can I pick it up from you at work?

[Origami]

Yes, it's at home today but I can bring it in tomorrow. I have to be out of town on Wednesday, so hopefully we can hook up tomorrow. I'll show you how to use it then.

[JMsAquarium]

I bought this '400' watt fixture that I currently have and use with the low PAR readings. Is it possible that I really have a 250w ballast running a 400w bulb? There are no numbers on the PFO ballast anywhere that I can find. Can a 250 power a 400w bulb? Do ballasts start producing less power as they get older?

 

Rob,

 

Here's a link to the readings we've done back in 2005 Par meter readings

 

You will find some info on 400W PFO ballasts readings (look for rows 60 to 62 and 68 to 73), which are way much higher than what you've got. I suspect a faulty ballast.

 

Happy readings

 

JM

[Boret]

I have a magnetic 400w PFO ballast if you want to borrow.

[zygote2k]

Here's the readings from the 150 tank that's 30" deep. On one side is a Hamilton 400w 14k and on the other side is a Hamilton 150w 20k. Both are suspended 9" above the water. Both are HQI South Pacific Supply bulbs.

 

400w

1" above 600

1" below 450

middle 125

bottom 70

 

150w

1" above 150

1"below 100

middle 35

bottom 20

 

This tank has a mix of softies and LPS which grow fast. There is a chunk of green slimer which is growing slowly and several different montiporas which grow fast.

[zygote2k]

Here's the readings from another maintenance tank. 125 gallon with 2) Hamilton 400w 14k DE fixtures 4" above the water.

 

1" above 710

1" below 520

middle 200

bottom 100

 

between the lights near the center brace:

 

1" above 015

1" below 020

middle 070

bottom 050

 

In hindsight, I've realized that the Hamilton fixtures with the beaded metal reflectors are inefficient.

 

 

I checked out Boret's incredibly vibrant colored 92g tank as well. He uses a Lumenarc with a 400w mh and 2 VHO actinics. I think his fixture was about 9" above the water.

At the lens 2000+

1" above 900

1" below 750

middle 500

bottom 250

 

Here's another maintenance tank- 90 gal with Current 2x250 mh w/ 4 T-5 actinics suspended 9" above the surface.

At lens 1400

1" above 550

1" below 350

middle 150

bottom 100

 

Here's an Aquapod 12

 

1" above 250

1"below 150

middle 075

bottom 050

 

Here's the recent 240 with 2) PFO 14k DE's suspended 14" above water surface. 30" deep tank

 

At lens 2k+

1" above 750

1" below 500

middle 250

bottom 100

 

Here's David Beasleys 75 with an AquaMedic 2x250 mh w/ 2 T-5's suspended 5" above the surface

 

1" above 1250

1"below 900

middle 500

bottom 350

 

 

After much testing, I'm beginning to realize the value in a good reflector like a Lumenarc. I also am seeing bigger PAR readings with 400w bulbs as opposed to 250's or less. Most of these tanks do not have chillers and run temps as high as 82. My opinion of a good light set-up to grow anything would be a 400w SE Mh with a Lumenarc reflector suspended about 10" above the water surface. As long as you have good ventilation, a chiller won't be necessary.

 

If anyone has PAR readings for their tank(s), please post them on this string so noobs and pros alike can use it for a database.

Edited August 29, 2009 by zygote2k

[zygote2k]

Borrowed an Aqua-Medic Starlight 20k 175DE with hammertone reflector while the 400 is getting fixed. Still 9" above water.

 

At lens 2k+

 

1" above 250

1" below 150

middle 75

bottom 50

 

This light reminds me of the days when I used to drop acid and look at the blacklight posters....

[Boret]

Good report of the findings. Where you able to test your light with the 400w magnetic ballast?

 

A small correction, my reflector is 8" from the water, and the light bulb is 9 to 9

[zygote2k]

New tank reading- "Amos" 90 gal with a 4bulb T5 setup about 6" above the water.

 

At lens 900

1"above 615

1"below 400

middle 150

bottom 75

 

The sps were all in the zone of 150+ and growing nicely.

[Boret]

Now that I think about it, we should have measured the PAR on the frag tank with the T5s.... oh well, next time.