How do YOU Par map?

[reef’r]

Rented an apogee from TSA to par map since I finally got my lights where I wanted, coral additions have stopped and I’m going to let the tank ride. I played around with it last night all at peak photoperiod both with current intensity and then where I think I want the tank. Is peak really the only time your usually worried about when par mapping or do you check all points of photoperiod and try and tune them in I feel like this would be most difficult because I would think at peak you would be way high. The apogee meter I rented I didn’t confirm the model but it’s the one with just the sensor on the end not the wand so you have to have your whole arm in the tank when taking readings and I feel like it throws them off a good bit but it’s a good general idea. I have it for another couple of days and I’m going to post up a fts, lighting rundown and show par numbers because I know how In depth I tried searching for this info with a specific lighting setup with percentages and schedules.

 

[EricR]

I only check/map at peak intensity.
Apogee MQ-510 that I've rented and/or borrowed from local reefer has a wand so I think that's basically a necessity.
*only done it 4 times so not a ton of experience but that's what I've done

 

[Lavey29]

Turn off all flow. Place sensor in as many areas as you want to par check throughout the tank with lights at your current intensity setting at their max daily intensity. I've only used the wand but can you place the sensor on a rock or sandbed and remove your arm?

If your par seems low increase intensity to get the numbers you want but be sure to go back to original settings. If you decide to increase intensity raise it 1% per day.

 

[BeanAnimal]

Turn off all flow. Place sensor in as many areas as you want to par check throughout the tank with lights at your current intensity setting at their max daily intensity. I've only used the wand but can you place the sensor on a rock or sandbed and remove your arm?

Not picking on you -- what you suggest is repeated regularly and appears to be the standard advice given. The question is why and under what reasoning, other than it is just passed on from person to person.

Ignoring the argument that PAR meters results (PPFD values) are not accurate and not overly useful to begin with...


What is is the purpose of turning off the flow? Coral do not live with the flow off and therefore spectral power with the lights off is an even more meaningless number that it was to begin with, especially if the returned values are different from those taken with the flow on.

If the idea is a "relative map" then you would want the flow on, even if the numbers themselves aer meaningless, but you are interested in the relative intensity at any area in the tank... then you would want to measure with the flow on, as that is where your coral will live.


:)

 

[Troylee]

Not picking on you -- what you suggest is repeated regularly and appears to be the standard advice given. The question is why and under what reasoning, other than it is just passed on from person to person.

Ignoring the argument that PAR meters results (PPFD values) are not accurate and not overly useful to begin with...


What is is the purpose of turning off the flow? Coral do not live with the flow off and therefore spectral power with the lights off is a meaningless number, especially if the returned values are different from those taken with the flow on.

If the idea is a "relative map" then you would want the flow on, even if the numbers themselves aer meaningless, but you are interested in the relative intensity at any area in the tank... then you would want to measure with the flow on, as that is where your coral will live.


:)

Agreed! I’ve never turned my flow off I just hold it where I want it and I take the average.. if my meter is bouncing 300-350 I call it 325 lol.. not that it’s ever gonna be precise but it gets me a ball park idea of what I’m working with a baseline if you will.. that’s still pointless to be honest haha! It’s fun to tinker thou.

 

[Pntbll687]

Not picking on you -- what you suggest is repeated regularly and appears to be the standard advice given. The question is why and under what reasoning, other than it is just passed on from person to person.

Ignoring the argument that PAR meters results (PPFD values) are not accurate and not overly useful to begin with...


What is is the purpose of turning off the flow? Coral do not liv with the flow off and therefore spectral power with the lights off is a meaningless number, especially if the returned values are different from those taken with the flow on.

:)

Turning off the flow let's you get a flat reading. When the flow is on, all the ripples focus and diffuse the light all over the place. With the flow off, a certain spot might read 300 par, but with the flow on, it could be as low as 150 one second and 500 the next.

You're using the meter to get a general reading, not a "i need to place this coral in exactly 100 par".

What size tank and lights are you using? You can probably find someone online who has mapped something close to what you have.

 

[mjszos]

Turning off the flow let's you get a flat reading. When the flow is on, all the ripples focus and diffuse the light all over the place. With the flow off, a certain spot might read 300 par, but with the flow on, it could be as low as 150 one second and 500 the next.

Does this not exactly prove the point that @BeanAnimal was making though? Maybe I'm missing something, but I do my readings with the flow on to see how the tank will look under its normal operating conditions. I leave the reader there for a few seconds, then eyeball the range.

It's not like your coral will ONLY grow under 198.58 PAR. And they can adjust. No reason to overcomplicate these things IMO.

 

[reef’r]

Turn off all flow. Place sensor in as many areas as you want to par check throughout the tank with lights at your current intensity setting at their max daily intensity. I've only used the wand but can you place the sensor on a rock or sandbed and remove your arm?

If your par seems low increase intensity to get the numbers you want but be sure to go back to original settings. If you decide to increase intensity raise it 1% per day.

Okay this is essentially what I did and yeah I tried sitting the sensor flat but wasn’t really doable as the wire wanted to twist it around, also tried a pair of tongs. I just tried to take 3-4 readings around each piece getting the most light I could on it. Like a lot of people have said it’s mostly taking averages I suppose

 

[reef’r]

Not picking on you -- what you suggest is repeated regularly and appears to be the standard advice given. The question is why and under what reasoning, other than it is just passed on from person to person.

Ignoring the argument that PAR meters results (PPFD values) are not accurate and not overly useful to begin with...


What is is the purpose of turning off the flow? Coral do not live with the flow off and therefore spectral power with the lights off is an even more meaningless number that it was to begin with, especially if the returned values are different from those taken with the flow on.

If the idea is a "relative map" then you would want the flow on, even if the numbers themselves aer meaningless, but you are interested in the relative intensity at any area in the tank... then you would want to measure with the flow on, as that is where your coral will live.


:)

Agreed! I’ve never turned my flow off I just hold it where I want it and I take the average.. if my meter is bouncing 300-350 I call it 325 lol.. not that it’s ever gonna be precise but it gets me a ball park idea of what I’m working with a baseline if you will.. that’s still pointless to be honest haha! It’s fun to tinker thou.

Turning off the flow let's you get a flat reading. When the flow is on, all the ripples focus and diffuse the light all over the place. With the flow off, a certain spot might read 300 par, but with the flow on, it could be as low as 150 one second and 500 the next.

You're using the meter to get a general reading, not a "i need to place this coral in exactly 100 par".

What size tank and lights are you using? You can probably find someone online who has mapped something close to what you have.

Does this not exactly prove the point that @BeanAnimal was making though? Maybe I'm missing something, but I do my readings with the flow on to see how the tank will look under its normal operating conditions. I leave the reader there for a few seconds, then eyeball the range.

It's not like your coral will ONLY grow under 198.58 PAR. And they can adjust. No reason to overcomplicate these things IMO.

I took readings with flow off and then just return pump on and the numbers do change but I’m really not looking to be that specific. I will do it again tonight with full flow and see what changes. @Pntbll687 i have a 40g cube running an xr15 pro, 4 t5 blue plus and two or4 60s blue plus. Hoping to be able to grow sticks bottom to top, I think it’s doable

 

[KrisReef]

Great discussion.

Having flow off may help remove some of the noise from the sketchy sensor and give a maximum number easier then trying to get the number steady with flow in the tank.

Light traveling across the air water interface is moving so fast does a coral light receptor protein even notice any reduction in inertia among the light particles it is catchin? ( I bet it's Par Meter is bouncing around like a fusion H+ ion at your favorite bomb testing site during a live test?)

 

[Pntbll687]

I took readings with flow off and then just return pump on and the numbers do change but I’m really not looking to be that specific. I will do it again tonight with full flow and see what changes. @Pntbll687 i have a 40g cube running an xr15 pro, 4 t5 blue plus and two or4 60s blue plus. Hoping to be able to grow sticks bottom to top, I think it’s doable

Sounds like more than enough light.

Instead of mapping out the par, why not just put some test frags in and see how they do?

 

[BeanAnimal]

I took readings with flow off and then just return pump on and the numbers do change but I’m really not looking to be that specific.

Why are you looking at all would be my question. .

Spectral intensity is higher at the top, lower at the bottom. Even lower in shadows. A bit higher near clean glass (reflection) and directly under lenses or lamps and lower the further outward you move.

All "par maps" look pretty much the same with regard to the pattern dictated by the number of fixtures and location of the lamp or emitters in each.

The actual numbers are insanely meaningless if any reasonable fixture is being used.

IMHO -- renting (or buying) a PAR meter is pointless for 99.99% of the people in this hobby. It is a misunderstood tool that amounts to an expensive feel good toy that for whatever reason, this hobby has decided is a must have instrument....

Nobody here can tell me what "PAR" a given coral needs, be it 182 or 473. There are just too many variables.

Flow on or off?
Angle of meter?
Cosine correction of sensor?
Brand of Sensor?
Meter compensation Curve?
Lack of Spectral information?
to name a few :)

So your reading and my reading could EASILY vary by as much as 50% fr the same fixture at the same settings and depth. 182 or 364? Which number is correct? What does the manual that came with the coral say? How do we know WHAT specific spectrum that 182 or 364 should be comprised of?

 

[KrisReef]

Why are you looking at all would be my question. .

Spectral intensity is higher at the top, lower at the bottom. Even lower in shadows. A bit higher near clean glass (reflection) and directly under lenses or lamps and lower the further outward you move.

All "par maps" look pretty much the same with regard to the pattern dictated by the number of fixtures and location of the lamp or emitters in each.

The actual numbers are insanely meaningless if any reasonable fixture is being used.

IMHO -- renting (or buying) a PAR meter is pointless for 99.99% of the people in this hobby. It is a misunderstood tool that amounts to an expensive feel good toy that for whatever reason, this hobby has decided is a must have instrument....

Nobody here can tell me what "PAR" a given coral needs, be it 182 or 473. There are just too many variables.

Flow on or off?
Angle of meter?
Cosine correction of sensor?
Brand of Sensor?
Meter compensation Curve?
Lack of Spectral information?
to name a few :)

So your reading and my reading could EASILY vary by as much as 50% fr the same fixture at the same settings and depth. 182 or 364? Which number is correct? What does the manual that came with the coral say? How do we know WHAT specific spectrum that 182 or 364 should be comprised of?

18+

 

[Lavey29]

Okay this is essentially what I did and yeah I tried sitting the sensor flat but wasn’t really doable as the wire wanted to twist it around, also tried a pair of tongs. I just tried to take 3-4 readings around each piece getting the most light I could on it. Like a lot of people have said it’s mostly taking averages I suppose

It was easier with a wand but do the best you can. Fixing my par was the best improvement in my tank in 4 years.

 

[reef’r]

Sounds like more than enough light.

Instead of mapping out the par, why not just put some test frags in and see how they do?

Tank has a lot of frags already. Growth is slow on some good on others. Have a lot of money hanging above the tank in lights and wanted to “put a cap on it” to say and just check par readings. I’m only a handful of months in to SPS and my eye for health on them goes about as far as polyp extension or tissue falling off

 

[SaltyWalty]

I took readings with flow off and then just return pump on and the numbers do change but I’m really not looking to be that specific. I will do it again tonight with full flow and see what changes. @Pntbll687 i have a 40g cube running an xr15 pro, 4 t5 blue plus and two or4 60s blue plus. Hoping to be able to grow sticks bottom to top, I think it’s doable

I agree. I took a reading with flow off, then took a reading with the flow on. I made note of the lowest and highest numbers I saw with flow on. This gave me a range as well as an average par number. Probably more than I needed but I enjoyed it

 

[BeanAnimal]

It was easier with a wand but do the best you can. Fixing my par was the best improvement in my tank in 4 years.

I will bite:

Keeping in mind that two fixtures with wildly different spectrums but the SAME "PAR" (PPFD) for a given spot in a tank will grow the same coral vastly differently...

What is exactly is "fixing your PAR"?

How were the "target" numbers derived?

Hows was the specific spectrum that correlates to the "target PAR" chosen?

How do you account for coral growing and the PPFD at all (any) areas of the tank being in a constant state of change (coral growth shadowing other corals and its own growth).

Sometimes we create false correlations because they feel and sound reasonable... when in reality we just got lucky :)



Take a look below:

Those two lamps (both great lamps) are worlds apart with regard to spectral output. They happen to have the same PAR (PFFD) readings. Without question, two tanks full of the same coral in each will have VASTLY different growth rates and coloration under these lamps. The real kicker is that some coral may thrive in one tank and some in the other....

Image courtesy of Dr. Sanjay Joshi as part of his Metal Halide lamp database and discussions from a dozen or so years ago....

 

[keithw283]

Turn off all flow. Place sensor in as many areas as you want to par check throughout the tank with lights at your current intensity setting at their max daily intensity. I've only used the wand but can you place the sensor on a rock or sandbed and remove your arm?

If your par seems low increase intensity to get the numbers you want but be sure to go back to original settings. If you decide to increase intensity raise it 1% per day.

Turning the flow off seems counter productive. Why wouldn’t you want to know the numbers for what the corals are actually experiencing?

 

[reef’r]

Great discussion.

Having flow off may help remove some of the noise from the sketchy sensor and give a maximum number easier then trying to get the number steady with flow in the tank.

Light traveling across the air water interface is moving so fast does a coral light receptor protein even notice any reduction in inertia among the light particles it is catchin? ( I bet it's Par Meter is bouncing around like a fusion H+ ion at your favorite bomb testing site during a live test?)

Why are you looking at all would be my question. .

Spectral intensity is higher at the top, lower at the bottom. Even lower in shadows. A bit higher near clean glass (reflection) and directly under lenses or lamps and lower the further outward you move.

All "par maps" look pretty much the same with regard to the pattern dictated by the number of fixtures and location of the lamp or emitters in each.

The actual numbers are insanely meaningless if any reasonable fixture is being used.

IMHO -- renting (or buying) a PAR meter is pointless for 99.99% of the people in this hobby. It is a misunderstood tool that amounts to an expensive feel good toy that for whatever reason, this hobby has decided is a must have instrument....

Nobody here can tell me what "PAR" a given coral needs, be it 182 or 473. There are just too many variables.

Flow on or off?
Angle of meter?
Cosine correction of sensor?
Brand of Sensor?
Meter compensation Curve?
Lack of Spectral information?
to name a few :)

So your reading and my reading could EASILY vary by as much as 50% fr the same fixture at the same settings and depth. 182 or 364? Which number is correct? What does the manual that came with the coral say? How do we know WHAT specific spectrum that 182 or 364 should be comprised of?

I do agree. I posted a thread in reef chemistry asking about finding stability in hobby grade test kits as I was having fluctuations from test to test. And then another happened last night. Hannah salinity stick saying tank was 1.019, refracto with BRS cal fluid reading like 40ppt (can’t remember the sg reading). Went and picked up a new bottle of fauna marin cal fluid and it’s bang on 1.026. Who the heck knows and seems as though par reading is just as back and forth I think when your taking in all the info that there is in this hobby and trying to find the all mighty STABILITY with parameters, lights, flow, nutrients, there’s just way too many tails to chase and probably end up doing more harm than good #allmy#allmymoneygoestocoral

 

[Lavey29]

Turning the flow off seems counter productive. Why wouldn’t you want to know the numbers for what the corals are actually experiencing?

Your premis seems accurate but I think the reason is the sensor is not as accurate with flow on so you're not getting a true reading from the sensor. The actual par to the coral is probably the same with flow on or off but not for the sensor.