So how do you get by without a PAR reading?

[BeanAnimal]

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).

You still ignoring the context of my comments and any common sense.

I did not say the AI prime was not usable on a 10g. I said the scenario that you proposed with low light soft coral at the surface right under the fixture at full output was ridiculous.

My advise and context was clearly not to put such a coral at the water surface and run the fixture at full intensity be it a 10 gallon tank or a 10,000 gallon tank — no matter how many ways you reframe it.

To that end, your premise regarding the nano somehow changing things makes no sense anyway. The intensity would be the same at the same xyz distance in relation to the light, it has nothing to do with tank size other than some possible reflective gain diminishing fall off near the edges. But that is countered by the fact that a larger tank with overlapping fixtures would have higher intensity at a given depth and similar reflective gain anyway.

Please stop reframing my words — it distracts from the actual topic at hand — my context was very clear and reiterated several times already.

 

[56longroof]

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.

Or just download the Photone app. Its free and reviews state it's fairly accurate. I downloaded it just out of curiosity to see what my halides were putting out at the waters surface.

 

[Punchanello]

If you are newer to the hobby or don't have a trusted buddy with experience who can come and take a look, a par meter can save a lot of time, money and frustration. Even if it's only to rule light out as a problem or give you a sense of where the light is stronger or weaker comparatively. Manufacturers guidelines are a good start but they are rarely that detailed and often don't account for things like tank depth or other variables.

Personally, I don't trust manufacturer advice because often you are getting a rosy description of the light's performance and not sensible advice on placement and intensity. eg. one leading manufacturers advice on a unit I bought was that it was so well designed and tuned I could just wack in on and turn it up to 100%.

 

[cba191]

I've heard good things about this one.

https://a.co/d/1t31DmC

 

[Dannyboy402]

I've heard good things about this one.

https://a.co/d/1t31DmC

I just bought this one! I read the reviews and I'm willing to try it!

 

[threebuoys]

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.

Sorry to write such a long response to yhour post.

I've read your posts in this thread with great interest. I believe I understand the shortcomings you see in using PAR meters in our hobby. I have to admit I have a seneye par meter I purchased several year ago. I will also admit the measurements I made at that time led me to believe my lighting was inadequate. As a result, I replaced my lighting with NooPsyche fixtures.

Your first paragraph caught my eye. You suggest manufacturers guidlines is a better starting point than anecdotal PAR measurements recommended by others. So, I went to the NooPsyche website to see what the MFG recommended.

(To my surprise, a link to your "NooPsyche Profile Generator" and website were highlighted on the instructions page. So, I read your article "PAR meters - Illumninating or Not" on the website that covers the same topics you've addressed in this thread.)

As you are aware from your NooPsyche experience, the mfg provides 3 demo settings - one for SPS, one for LPS, and one for SPS?LPS.

My long- winded question, how does one refine the settings to suit their own reef tank? Once the mfg recommendation is set, is it all trial and error? Other than visual confirmation that over time the tank improves or gets worse, what can the hobbyist (me) do?

If the PAR from the lights I replaced is much different, I'm talking 50 or 100 or 150 PAR lower than that from the new lights, how should I proceed.? If a coral vendor recommends a PAR range for a particular coral species that is different than the light mfg, which answer should I lean towards - the coral vendor or the light mfg? Do light mfg's know more than the coral vendors?

I realize these are difficult if not impossible questions to answer. That is not very satisfying as you might imagine. If attempting to use PAR to help find an answer is not appropriate, what tools are appropriate other than trial and error on a tank-by- tank basis (also not very satisfying)?

And please understand, I am not disagreeing with anything you've said. I'm just missing the piece of the puzzle that I need to use to manage lights rather than a tool (PAR) that seems to be a widely misunderstood.

 

[RelaxingWithTheReef]

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

Welcome to R2R, and best of luck with your tank.

In the @BeanAnimal world the fact is, there’s simply no need for a PAR meter. The values measured are hopelessly inaccurate, and all of the PAR meters belong in the trash can.

Following this idea to its inevitable conclusion means that naturally all the PAR values given by vendors, successful reefers, and scientific studies, etc. are all rubbish, and should be disregarded. In fact, since they are all wrong or misleading, let’s remove ALL reference to PAR and PAR values from R2R and from the internet.

Then you have to ask yourself, has the void created by this lack of “useless” data hurt or helped the hobby and the scientific community. I would argue that it would hurt.

Mr. Bean also argues that people in general misunderstand the reading, and they don’t know how to use PAR meters correctly, and this also makes PAR values hopelessly useless. I really take exception to this as being very condescending and offensive. Yes, there are reefers that are still learning how to use the meter correctly, and do not fully understand the underlying principles. But make no mistake about it, reefers in general are very smart and intelligent people that, given research and education, are fully capable of understanding how to use a PAR meter correctly, and also understand its limitations. To think otherwise is very disrespectful in my opinion.

Since only a few posts were actually responses to your question, I will offer my opinion.

Unfortunately to my knowledge there is no 3D light simulation software available to reefers that model or predict the quality of light a given coral is exposed to in your tank. It would be quite complicated to develop because of the number of variables involved, and the need to map the 3D space to have reasonable accuracy. The source(s), and the reflections of the glass and rock and surrounding corals all play a major roll in determining the absorption and reflection of the available light. Also for a given height in the tank, the exact location of the coral in the tank can easily produce +-50% changes of light intensity. So at the end of the day, without a PAR meter for guidance, it really comes down to trying to find a similar setup with similar lighting as a starting point, and applying a best guess based on past experience. Some people are very good at it, while other people like me are not.

I am absolutely terrible at estimating light. I’m lucky to tell the difference between 100 PAR and 450 PAR. Keep in mind that corals and zoas etc. can be easily damaged and irreversibly burnt by excessive light, especially LED light. Once overexposed, a coral may take weeks or months to recover, or may quickly or slowly die. This can happen even if the animal is subsequently placed in the most ideal conditions. Unfortunately the fatal damage has already been done.

This is why in a case like yours, I simply use a quality PAR meter to establish a reasonably safe baseline starting point of Low PAR (around 60-100 PAR) for something like Zoas, Medium PAR (around 100-150) for LPS, and High PAR (around 250-350+) for SPS. I always error on the low side, and slowly increase the intensity over the course of weeks, while carefully watching the coral’s response.

In my opinion I believe the typical overall error of a PAR measurement is probably around 20%, maybe 30% or even 40% for a really low quality meter. Always keep this in mind, and adjust accordingly.

I want to be clear that I do not consider a PAR meter as mandatory. There are many very successful reefers that never measured PAR. But with that said, I do consider it to be a valuable tool. This is especially true since the wide adoption of high intensity LED lighting that has a long history of burning coral much more easily that older “foolproof” T8, T5, and Metal Halide lighting.

Now that I explained my technique, maybe Mr. Bean would be so kind as to explain to us exactly, without glossing over details, how he would go about setting up lighting using “manufacturers guidelines” for a 75g narrow, deep, and wide ZOA tank without the assistance of a PAR meter. I’m very interested in understanding the details of his technique, and I’m always keen to learn something.

 

[Freenow54]

Well I stand by my experience . Using an Apogee and really helped to find sweet spots , and also areas that the light was blocked ie weaker. To each his own

 

[BeanAnimal]

In the @BeanAnimal world the fact is, there’s simply no need for a PAR meter. The values measured are hopelessly inaccurate, and all of the PAR meters belong in the trash can.

Tthe tone of your post is sarcastic, filled with exaggeration and strawman arguments.

But let's pretend that the post was made in good faith instead of being a backhanded personal screed.

First, I’ve never suggested removing all reference to PAR from the hobby. What I have consistently said is that PAR, as it’s commonly used, shared and interpreted, is misunderstood, unreliable and overvalued.

Second, nothing I’ve written is intended to be condescending or disrespectful. I’m not questioning anyone’s intelligence. I am pointing out that many hobbyists -- even experienced ones -- rely on tools, metrics, and passed on lore without fully understanding their limitations or the margin of error involved. That’s not an insult by any means. It is a practical observation that applies to any technical hobby.

I’m clearly not against tools, I build them, write them and share them and have for over 2 decades in this hobby. I am against misplaced confidence in tools that aren’t being used or interpreted correctly. I am against propagation of poor information, methods and ideas.

Your method of starting low, ramping slowly, and observing coral response? That’s exactly what I’ve advocated for years, and in this thread and every thread like it. You don’t need a meter flashing an arbitrary number to do that properly or well.

You actually also reinforced another one of my main points: stating a ±50% variation in light levels from simple placement changes. If we combine that with a stacked error that can easily be 20–40%, makes it difficult to claim precision -- let alone "ballpark" utility.

So in the end, you clearly have no idea what my actual position is, or have ignored it in favor of attempting to be insulting for the sake of doing so, all while actually unintentionally reinforcing the core components if it.

As for your closing remark: I’ve explained my methods many times across these forums. I suspect you already know exactly what I would say. Framing it as “maybe Mr. Bean can finally explain himself” is transparent passive aggression -- it is arrogant and uncalled for. It undermines the very civility and scientific integrity you just called for. If your intent is to actually exchange ideas, let’s do that -- without the silly posturing and attempts at personal insult.

 

[BeanAnimal]

Sorry to write such a long response to yhour post.

I appreciate that you took the time to read the article and ask. Your response isn’t too long or a waste of time at all.

You’re absolutely right! Once you start with the manufacturer’s profile (or even someone else’s advice), it becomes a process of observation, patience, and refinement. That is the actual tool -- watching how corals respond over time. There’s no real shortcut. A PAR meter doesn’t change that or offer a reliable shortcut. People often say “it’s just a starting point,” but that overlooks the massive variation between fixtures, spectrum, PUR, coral species, water chemistry, and even the meters themselves.

And to clarify my earlier point -- when I mention manufacturer guidelines, I mean that reputable vendors can usually give a solid starting point in terms of tank size, number of fixtures, and general coverage. They are noot perfect values, but do give a starting point. On the other hand, PAR numbers from coral vendors are far less helpful, since every tank, light source, spectrum, and environment is different. The numbers rarely translate meaningfully across systems -- and like any new addition, should be started low and out of direct light and slowly moved toward higher light as response is watched.

 

[RelaxingWithTheReef]

Tthe tone of your post is sarcastic, filled with exaggeration and strawman arguments.

But let's pretend that the post was made in good faith instead of being a backhanded personal screed.
I responded in good faith to what I believe to be the propagation of poor information and ideas that can potentially result in the unnecessary harm to corals.

First, I’ve never suggested removing all reference to PAR from the hobby. What I have consistently said is that PAR, as it’s commonly used, shared and interpreted, is misunderstood, unreliable and overvalued.
This is exactly what I am talking about. You simply believe that people in general misunderstand and misinterpret PAR. You clearly think you know (but in reality you have absolutely NO idea) how the vast majority of people think, understand, and interpret PAR results. It’s extremely condescending and disrespectful to assume people in general, lack the intelligence and education needed to use the instrument properly.

I’m clearly not against tools, I build them, write them and share them and have for over 2 decades in this hobby
Congratulations on your 2 decades. I hate to admit it but I started in the hobby as the Berlin Method was being developed over 5 decades ago. It was a time when Clownfish, under-gravel filters, pink tipped anemones, and Aqua-Lux lighting ruled the day!

Your method of starting low, ramping slowly, and observing coral response? That’s exactly what I’ve advocated for years, and in this thread and every thread like it. You don’t need a meter flashing an arbitrary number to do that properly or well.
This statement contains a falsehood. The flashing number is not arbitrary in my opinion. It’s a useful number if interpreted properly. In my opinion having a properly interpreted PAR number can provide a more accurate starting point than for example a simple guess made by someone lacking practical experience. This can obviously result in an improve outcome for coral.
We agree to disagree on this point.

You actually also reinforced another one of my main points: stating a ±50% variation in light levels from simple placement changes.
This is a misinterpretation of my statement. The +-50% variation across the same level of a tank in my statement reinforces the need for a tool that provides a way to measure local light intensity exactly where a coral is positioned.

If we combine that with a stacked error that can easily be 20–40%, makes it difficult to claim precision -- let alone "ballpark" utility.
As I previously stated, you believe PAR readings are so badly flawed and so grossly misinterpreted that they are useless. From personal experience I believe without a shadow of a doubt a quality PAR meter provides sufficient accuracy to establish a safe “ballpark” starting light level. Certainly better than an uneducated guess.
We agree to disagree on this point.

As for your closing remark: I’ve explained my methods many times across these forums. I suspect you already know exactly what I would say. Framing it as “maybe Mr. Bean can finally explain himself” is transparent passive aggression -- it is arrogant and uncalled for. It undermines the very civility and scientific integrity you just called for. If your intent is to actually exchange ideas, let’s do that -- without the silly posturing and attempts at personal insult.
Respectfully asking you to clearly explain your method in detail is in good faith and not a personal insult by any stretch of the imagination. Playing the personal insult card is grossly inappropriate and unprofessional. Once again, you may think you know, but in reality you have no idea what I or other people know, or what we are thinking. To be clear I, and I suspect many readers of this thread, are not familiar with your exact method, and we certainly don’t have time to search through R2R in search of it.

Again, I am very interested as I’m sure the OP is, in knowing exactly how you determine the initial intensity settings of a novel tank using “manufacturer’s guidelines” while minimizing the risk to the corals. As a reminder, this was in fact the OP’s original question. Quite frankly I'm surprised by your friction and reluctance to answer that simple question.

I clearly explained my proven method in detail, and now you have an opportunity to clearly state your method in detail. From there the readers of the thread can form their own conclusions.

With that, I made my point, and it's time for me to move on.

 

[BeanAnimal]

I responded in good faith to what I believe to be the propagation of poor information

There was nothing “good faith” about your post or your tone. It was a thinly veiled personal attack, full of condescension, strawman arguments, and a gross mischaracterization of my position. If your intent was to provide helpful information to the OP, you could have done so without any of that.

This is exactly what I am talking about. You simply believe that people in general misunderstand and misinterpret PAR. You clearly think you know (but in reality you have absolutely NO idea) how the vast majority of people think, understand, and interpret PAR results. It’s extremely condescending and disrespectful to assume people in general, lack the intelligence and education needed to use the instrument properly.

Except I am responding directly to you -- and to others in these threads -- by engaging in a clear, reasoned exchange about how people interpret and use PAR. I am not guessing what you think, you are arguing what you think. That is the conversation. In this case you chose to make this personal instead of sticking to the points -- while posturing from the very position of condescension and disrespect you’re accusing me of.

Disagreement is not disrespect. Offering a different view is not condescending. The only person in this thread behaving with condescension, dismissiveness, and personal attack is you.

No matter how you reframe my position, opinion or responses, I have not attacked or been disrespectful to you or anybody else.

Respectfully asking you to clearly explain your method in detail is in good faith and not a personal insult by any stretch of the imagination. Playing the personal insult card is grossly inappropriate and unprofessional.

Again - there was nothing respectful or "good faith" about your post or request. Softening your tone after being confronted and playing victim after launching a direct attack is not only disingenuous, it’s transparent.

 

[Reef Puncher]

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

i didnt. it was one of the first purchases i made. i still use it occasionally when i move corals around to verify they are getting correct light. i have gone through a few. if i had to recommend one it would be this one. for $125 it works well. this link here.


But. there is another option. your phone. theres an app called photone. you spend $7 buying the blue white LED filter option, and you have a par meter. you would also need a waterproof phone case, or just buy a underwater camera bag for $10.

it works, works well if used correctly, and for $17 its impossible to beat. its not quite as accurate as the first one i linked, but were talking off by like 5%.

 

[Freenow54]

I am the same but at my one local lfs they leaned into heavy blue. They said coral are used to fighting for benefits at deep levels. I don't know in the wild if I lived near the Nile river I think I would move