So how do you get by without a PAR reading?

[obsessedfishlady]

This is not great advice. People routinely cook their corals with newer LEDs. Get one of those cheap 90 watt popblooms or whatever and you'll see how it's possible.
You'll find 400 par in the center and like 150 par 4 inches to the side on tons of LEDs if they're at an incorrect height and have poor spread.

You are making my point without realizing it. It is not the 400, but rather what spectrum comprises that 400.

200 of the wrong spectrum could burn a coral where 400 of the proper spectrum would allow it to thrive.

PAR and PUR are not interchangeable and we can’t measure PUR, nor do we have a PUR guidebook even if we could.

You might have success without a par meter but telling people that you can crank an LED to 100% and not kill anything is irresponsible.

There was clear context to my statement. Any established fixture will have general sizing guidelines. Follow them and community feedback, and you will be fine. Some China black box with no reliable information? It is not a PAR meter that you need, but rather common sense. You ram the intensity over a period of time and stop when you get a negative impact. It makes no difference what a PAR meter reads.

The point of a PAR meter isn’t to grab an exact measurement (or at least that’s not how I see it)- it’s to aid in choosing an intensity that isn’t too high. Like I said you CAN get by without one just by simply watching your corals but if there’s a tool that can aid that process/the stress and possibly prevent losing any corals to start - why not use it?

Like I said you can take pics to compare days later. However, and this is my opinion and that is yours, PAR meters are helpful in gauging an idea. If your corals are dying and you assume it’s light (when really it was bad water quality or pests) a PAR meter can assist in confirming light isn’t the issue. They literally put PAR readings on the back of light boxes or in the manuals to help assist gauging where the light intensity should theoretically be set. So you claiming to use the manual/manufacture suggestions is still you supporting PAR readings because that’s where those suggestions come from. A manufacture didn’t throw corals in a tank, set the intensity by guessing, and say “hey I’m gonna sell this with this recommended intensity because this is what worked for me”. I would never crank a light to 100% ever to start with like you claimed in your original post but then just contradicted by saying you’d crank it slowly.

If that’s still your opinion that’s totally fine, it’s ok to have a different option!! I agree they aren’t a necessity so we’re halfway on the same page, but it’s ok to enjoy the tool also and I don’t think PAR meters have ever killed any of my corals.

 

[Reefer Matt]

I’m not going to debate par meters, but will offer this: If you (anyone) are curious about them, then get one. Borrow, rent, or buy one. Talking about it isn’t going to establish an objective opinion for you, it will just create arguments. Everyone has a different experience, and sometimes you just gotta find out for yourself.

 

[RaleighReefer]

Look at some online par charts to get an idea, but realistically hobbiest survived 20 years without these readings. Acclimation is key in absence of more data.

 

[BeanAnimal]

The point of a PAR meter isn’t to grab an exact measurement)… it’s to aid in choosing an intensity that isn’t too high.

Those statements are somewhat at odds with each other. There is no known reliable target. A value of, say 250 under 5 different fixtures of varying spectrum is not the same even if there was a known target. Add to that the differences and meters and user error, and there isn’t even a “range” that really means anything. Just feel good numbers that have no real correlation.

They literally put PAR readings on the back of light boxes or in the manuals to help assist gauging where the light intensity should theoretically be set

And for decades car stereo manufactures put meaningless power ratings on product boxes, and we can find countless other parallel marketing examples.

They meant absolutely nothing. Don’t confuse marketing trends and copycat efforts with meaningful data. Of course they put PAR numbers on boxes, it is what the misinformed buying mass expects. There are no standards or accredited procedure being followed, it is BS marketing bullet points.

I would never crank a light to 100% ever to start with like you claimed in your original post but then just contradicted by saying you’d crank it slowly

Nor would I or advise anybody to. At this point you are ignoring rather clear context to argue in bad faith, that’s on you not on me.

If that’s still your opinion that’s totally fine, it’s ok to have a different option!!

I tend to argue based on known facts. In this case regarding what PAR is actually measuring vs what people conflate it with measuring and the insane variance in measurement devices and methods that make the results even less meaningful even if we did have a valid target for a given coral.

Spectrum matters, a lot.

Want to argue PUR and a reasonable way to measure it? I am all ears. Otherwise my point stands. The tool does not do what people think it does and even if it did, there are no targets. So you are certainly free to your opinion, and if you wish we can have a conversation about if the facts supporting it or not.

 

[56longroof]

This is not great advice. People routinely cook their corals with newer LEDs. Get one of those cheap 90 watt popblooms or whatever and you'll see how it's possible. You'll find 400 par in the center and like 150 par 4 inches to the side on tons of LEDs if they're at an incorrect height and have poor spread.

You might have success without a par meter but telling people that you can crank an LED to 100% and not kill anything is irresponsible.

Its not the wattage that cooks them. More like improper spectrum. My halide/T5/CF combo puts out way more wattage than probably most if not all LED options available. I haven't cooked anything at all. In fact I have some acros 3" below the waters surface that are growing like crazy.

 

[BeanAnimal]

Its not the wattage that cooks them. More like improper spectrum. My halide/T5/CF combo puts out way more wattage than probably most if not all LED options available. I haven't cooked anything at all. In fact I have some acros 3" below the waters surface that are growing like crazy.

The overarching importance of spectrum is one of things being absolutely lost as people wrongly focus-on and promote PAR as the metric to base suitability on. Spectrum matters, a lot.

 

[rtparty]

Woohoo! Another PAR meter argument

 

[Reign1]

Im trying my local forums to rent a PAR meter and so far no luck. Just wondering how you guys got by without one. My 75 g is narrow and deep vs wide. Im a beginner converting fish only to coral. Main focus for now is Zoa's and a mushroom, pulsing xenia

Most LFS will rent you one. I did that once.
Also if you are running a moderate quality light and have mid settings your Zoas are likely fine.
I keep mine on the bottom and they aren't getting much par. 50-80 idk

 

[obsessedfishlady]

The point of a PAR meter isn’t to grab an exact measurement)… it’s to aid in choosing an intensity that isn’t too high.

Those statements are somewhat at odds with each other. There is no known reliable target. A value of, say 250 under 5 different fixtures of varying spectrum is not the same even if there was a known target. Add to that the differences and meters and user error, and there isn’t even a “range” that really means anything. Just feel good numbers that have no real correlation.

They literally put PAR readings on the back of light boxes or in the manuals to help assist gauging where the light intensity should theoretically be set

And for decades car stereo manufactures put meaningless power ratings on product boxes, and we can find countless other parallel marketing examples.

They meant absolutely nothing. Don’t confuse marketing trends and copycat efforts with meaningful data. Of course they put PAR numbers on boxes, it is what the misinformed buying mass expects. There are no standards or accredited procedure being followed, it is BS marketing bullet points.

I would never crank a light to 100% ever to start with like you claimed in your original post but then just contradicted by saying you’d crank it slowly

Nor would I or advise anybody to. At this point you are ignoring rather clear context to argue in bad faith, that’s on you not on me.

If that’s still your opinion that’s totally fine, it’s ok to have a different option!!

I tend to argue based on known facts. In this case regarding what PAR is actually measuring vs what people conflate it with measuring and the insane variance in measurement devices and methods that make the results even less meaningful even if we did have a valid target for a given coral.

Spectrum matters, a lot.

Want to argue PUR and a reasonable way to measure it? I am all ears. Otherwise my point stands. The tool does not do what people think it does and even if it did, there are no targets. So you are certainly free to your opinion, and if you wish we can have a conversation about if the facts supporting it or not.

I won’t continue to argue anymore for the sake of the poor OP who didn’t ask for it.

I agree spectrum is most important. They do make PAR meters that read spectrum. If I had the money that’s the route I’d go ($500+) - but as I said though I agree it’s not a necessity I’d rather spend my money elsewhere and measure my lights intensity as an aid using my cheap PAR meter personally. If it worked for me (and many others) why demand people shouldn’t have them? It’s not hurting you so there is no reason to be rude just because your opinion differs. It’s ok to agree to disagree.

If they want to explore that option let them explore it - they either will like it or they won’t and they should be allowed to make that decision. They didn’t ask if a PAR meter was worth it - they asked where they could get one and what ways they could go about not having one if they wanted to. Not what the specifics of whether or not having one is tried snd true.

I came here to answer the question not be bashed by some “know it all” in the reefing community. There are many successful reefers that have completely opposite ways of how they do things. It’s totally fine to do things differently than the next person - if it works it works and there is no harm in it.

 

[X-37B]

Never used a par meter until I went to 100% leds.
I use the par meter to get an even blanket of light across my system.
Currently 250 par on the bottom and 450-500 across the top of the rockwork on my 60×30×22 150.
These are just numbers that show me the distribution of light across my system.
Same for my 50g running 3 xr15's.
With 2 the par was, verified by my par meter' as not even across the 30×24 area.
Adding the 3rd 15 helped even out the distribution of light across the 30×24 area.

So I don't really use the meter for a number per say but to ensure complete coverage of my systems.

 

[obsessedfishlady]

Woohoo! Another PAR meter argument

This is common? Noted I’ll avoid PAR discussions for now on due to my lack of impulse on replying . I hate to disappoint but I blocked him to avoid my temptation to continue arguing .

 

[BeanAnimal]

They do make PAR meters that read spectrum.

Yes, but not in a meaningful context here. Unfortunately It is more data that feels like it should be important, but has no means to correlate it to a standard target or tie it to PUR.

If it worked for me (and many others) why demand people shouldn’t have them? It’s not hurting you so there is no reason to be rude just because your opinion differs. It’s ok to agree to disagree.

1. Confirmation bias and false correlation are powerful forces and they’re central to this discussion. Much of the hobby clings to certain practices not because they’re proven, but because they’ve been repeated and accepted without challenge. This isn’t a critique of anyone’s intelligence; it’s a reflection of how groupthink operates in any community. This is but one of dozens of examples in reefing.

2. I’ve been neither rude nor personal. My posts have been direct, factual, and respectful. Disagreement is not hostility.

3. Your wording implies that I’m demanding compliance or wish to restrict others, which isn’t accurate. I’m offering a fact based perspective to counter common misconceptions and share knowledge. See point #1 for why that matters.

They didn’t ask if a PAR meter was worth it - they asked where they could get one and what ways they could go about not having one if they wanted to. Not what the specifics of whether or not having one is tried snd true.

Context in a conversation matters. Broader discussion often emerges in these threads and that's how knowledge gets shared. It’s about offering perspective for the OP or anyone following along.

I’m not being combative or disrespectful, but rather just contributing to the exchange of ideas. Disagreement isn’t a personal attack. If we reduce every thread to narrow answers, we miss the opportunity to actually learn from each other.

I came here to answer the question not be bashed by some “know it all” in the reefing community.

You chose to engage, and I’ve responded respectfully to each of your points. Disagreement is not the same as being “bashed.” If you’re allowed to disagree with me, surely I’m allowed to do the same.

That said, personal attacks have no place here. They don’t add to the discussion and only undermine your position.

I don’t claim to know everything, but I speak where I have experience and understanding. I try to stay out of discussions or debates where that’s not the case.

 

[fish_collector]

I came here to answer the question not be bashed by some “know it all” in the reefing community.

I rarely enter into lengthy debates because I just don't care enough about it to do so. But I feel the need to point something out here, no one is "bashing" anyone, not once did BeanAnimal say anything about you personally. He will often quote a post that he feels is inaccurate and try to offer insight as to why, but he never "bashes" anyone.

I'm not exactly sure what BeanAnimal's technical background is, but he's been around these forums for perhaps 20 years or more and has tried very hard to debunk the myths and untruths in the reefing community, so I guess you could say he is a "know it all".

I've been a professional auto mechanic for nearly 40 years, in a car repair forum anything that I'd say I would expect to be taken as gospel without debate, in that case Id also be a "know it all". My point is, before you go getting all offended over someone's words, take a step back and reread what the person is trying to say, it is possible that person DOES know what they're talking about.


I don't know BeanAnimal personally, but I've headed his advice with a lot of things regarding my reef tank.

I own an Apogee PAR meter, I've used it a few times here and there. I'm not so sure that the information I get from it is useful or not. I can get a better understanding of my corals light needs with some simple trial and error adjustments, the $500 that I spent on the Apogee could have gone towards something else, retirement perhaps.

 

[Hooz]

Do it old school like we did 20 years ago. 2.25 watts per gallon for SPS and 1 watt per gallon for LPS. Par meters on Amazon cost ~$120 though.

Ryan did a test recently over at Serious Reefs and found that 1 watt per gallon with 75% of the wattage dedicated to "blue" channels and 25% of the wattage dedicated to "white" channels got right in the ballpark for LPS using 7 or 8 different fixtures (from Ecotech, to AI to Nicrew to Popbloom.

The number for SPS was right around 2.75 watts per gallon with the same color mix.

That assumes that the mounting height is "correct", but he did it using a $30 Amazon watt meter. It was pretty cool to see.

 

[Hooz]

The overarching importance of spectrum is one of things being absolutely lost as people wrongly focus-on and promote PAR as the metric to base suitability on. Spectrum matters, a lot.

And the point seems to be continually lost on you that pretty much EVERY current reef-centric LED fixture uses very similar diodes and have very similar spectrums. You could (and will) split hairs on one peaking at 445nm and another peaking at 455nm, or one having a touch less 450nm and a touch more 400nm, but in reality it is "close enough".

Overlay a Radion spectral graph on a Nicrew spectral graph. They might not be identical, but they're darned close.

You also like to talk about 5% differences in PAR meters, or us not knowing if a coral likes 83 PAR or 88 PAR or whatever... To that I say there are recommended RANGES for different coral types. 50-150 PAR for LPS and softies is a pretty broad range. Just shoot for the middle and then it doesn't matter if your meter is off. It's not as difficult as you make it out to be. And the argument that "we don't know if it's off 5% or 10% so it's useless" is a tired one, and just plain bad advice.

And, yes... I have an IM Nuvo 10 with a single AI Prime over it. If I run my schedule at its max as you suggested earlier, the entire tank is 300 or more PAR, peaking at almost 600 at the top of the rockwork. I'd pity the person trying to grow a zoa garden or mushrooms in there. But, hey, you said it'd be fine, right?

 

[BeanAnimal]

And the point seems to be continually lost on you that pretty much EVERY current reef-centric LED fixture uses very similar diodes and have very similar spectrums.

Nothing is “lost on me” and they don’t have similar spectrums at 100% all channels, and that is ignoring presets or user adjustments.

, but in reality it is "close enough".

I would ask what By what metric is “close enough”. Is the difference 2%, 20% or some other arbitrary number? How does that correlate to PUR?

Your argument is and has been fixtures — although with different diodes, drivers, counts, optics and bins — are close enough. PAR meters —although different — are close enough. User settings, measurement error differences from tank to tank and person to person and everything else is close enough.

That is a dizzying number of variables — error stacking we would call it — to be “close enough” — especially given that nobody can actually define a valid target to begin with.

And, yes... I have an IM Nuvo 10 with a single AI Prime over it. If I run my schedule at its max as you suggested earlier, the entire tank is 300 or more PAR, peaking at almost 600 at the top of the rockwork. I'd pity the person trying to grow a zoa garden or mushrooms in there. But, hey, you said it'd be fine, right?

Or a 150w halide — It is not a reasonable scenario to begin with and I suggested nothing of the sort unless you purposefully ignore context and reframe it in favor of creating a ridiculous scenario.

 

[EliMelly]

There is simply no need for a PAR meter. Use any common fixture and size according to manufacturers guidelines, even at 100% you are not likely going to have too much light. Low light corals deeper and in shade, high light corals higher.

Without getting into details, PAR meters are not nearly as useful as people think they are. The hobby promotes them due to misunderstanding, people feeling they are measuring something important to some arbitrary level of accuracy and imaginary guideline… and simple confirmation bias. Advice that they are must have devices is well meaning, but misguided.

The number on a meter doesn’t matter at all… how a given coral responds does matter. You will quickly start to understand how moving corals around affects their growth. Way too much light becomes obvious as tips burn and way too little light as they wither. There is no magic PAR number, or dare I say “ballpark” for any coral. It depends on spectrum, flow and system biome. The same coral in one tank under 400 ppfd may thrive under a different fixture in a different tank under 200 ppfd.

I am following this lately and it’s going great.

 

[robanister]

Search or ask others with similar setups what they have theirs at. Of course someone who has measured par

 

[Hooz]

Or a 150w halide — It is not a reasonable scenario to begin with and I suggested nothing of the sort unless you purposefully ignore context and reframe it in favor of creating a ridiculous scenario.

If you browse the nano tank forum right here on R2R, I think you'll find that the 10-15g nano tanks are VERY popular, and the AI Prime (or similarly powered lights) are overwhelmingly "the choice" for those tanks.

Not only is it a "reasonable scenario", it's a VERY common one. Following your advice would have a lot of people melting coral and wondering why. A quick check with a PAR meter would save a lot of headaches (and coral).

 

[redfishbluefish]

Not interested in getting into the minutia of PAR and PUR, but for what little time you use these meters and their associated costs, get a LUX meter. For 15 to 20 bucks you get the numbers you need to get into the ballpark. Unless you're doing heavy duty research, LUX is the way to go. He's no longer here, but search @saltyfilmfolks . To simplify the work he did, for LEDs, a peak LUX of 20-25K at the surface will keep your corals happy.