# PAR and PAR readings



## Themuleous (6 Oct 2010)

PAR seems to be creeping into this side of the hobby more and more, I guess from the marine side.  Does any actually have a PAR meter? I've spent ages looking and cant for the life of me find one for sale.  Within reason, does it really make that much difference to us planted people?

Just curious that's all 

Sam


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## Ian Holdich (6 Oct 2010)

Hey Sam, i saw some PAR meters for sale in Maplins the other week. 

http://www.maplin.co.uk/Module.aspx?Mod ... 7&T=Module

seems quite cheap, to me!

I have also noticed PAR become more of a buzz word on ther forums i frequent.


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## Themuleous (6 Oct 2010)

Not sure if that measures PAR or not, this is more the price I thought they were!

http://www.specmeters.com/Light_Meters/ ... Meter.html

Sam


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## George Farmer (6 Oct 2010)

I don't think PAR is as necessary in the planted tank hobby, as we all pretty much know by now that most plants can be grown in what used to be considered "low lighting" providing there is good nutrients and circulation.

Having said that, if you wish to grow a demanding carpet plant then it may be useful to know your PAR at the substrate, and in the corners of the tank to ensure the lighting is capable.  Figures of 50 to 100 Âµmol photons/m2/second are generally banded around as a good figure for the most demanding plant species.

In the reef hobby some photosynthetic corals i.e. most SPS demand high lighting so PAR is the most useful light measurment.

PAR is also useful to compare lighting types.  PFK did a comprehensive lighting review a few months ago and LED units did well, generally.  Even though they may not have appeared so bright to us, their PAR was relatively high.

I did use a PAR meter a while back, that I borrowed from PFK.  I didn't bother with it much, as I've never really had an issue growing plants with my usual 2 x HO T5 in most tank sizes.  

In retrospect it would have been interesting to compare lamp spectrums i.e. cheap 6500K vs. plant growth tubes (pinky, purple).  Although the pink/purple tubes may appear duller than 'daylight' specturms to us, they may have higher PAR.


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## Themuleous (6 Oct 2010)

Interesting, cheers George.  Much as I thought really.

Sam


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## Garuf (6 Oct 2010)

Hmmm, I don't know, I think there's definite room for them, especially then you're receiving odd growth habits or testing an untried light or lighting method. Sanj's huge tank and tyrophagus's swamp creek spring instantly to mind. 
The case of swamp creek stands out particularly in my mind as none of us thought light was an issue till the PAR metre came out and it showed the tank to be exceptionally low lit. I think that there's definite room if you're in these applications, and more so if it's one of these hyper wide tanks that are appearing, for a standard sized tank however, I think the old two tubes + reflectors will always dominate. Just my 2p's on the matter.


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## GreenNeedle (6 Oct 2010)

The cheap one in the post above is not a PAR meter.  It does say light but it's not really light if you know what I mean.  probably a lux meter which is lumens which is no use to man nor beast.  It should actually be called a 'brightness meter'.

Sam's is the real thing.  Quantum meter.

However the quantum meter actually measures many things and you buy different sensors dependent on what you are testing for.  No point having a quantum meter with an ultra violet sensor expecting to get a usable PAR reading 

Last time I look an Apogee Par meter with the applicable sensor etc was circa Â£250

As George and others say.  Unless you really are trying to dial in your light or are mega interested in the subject then that is one large outlay 

The use of the PAR meter on barrreport has seen many users actually winding down their light after being surprised that they actually had more than they needed.  MH users especially found they are way over cooking it but they were following the use of the MH on ADA tank.  That was due to those ADA MH setups somehow only giving out low light whilst still being the same power consumption.  A little bit of a no brainer that IMO but there you go 

The days of the Fitch family article suggesting Amano uses 3,4,5WPG are gone.  How it was ever alive when Amano himself says he uses low light is another story.

Now that LED and eventually plasma etc is coming into play then the PAR meter may well become something pretty useful. Maybe it will be something like in the US where a couple of people have it and ship it around to others, however we Brits don't like to let somethng like that out of our sight 

For ecample, my LED setup doesn't look as bright as an equal wattage T5HO setup with the same K.  That is Lumens. It is bright enough and clear light too.  However I have no idea the actual PAR coming out of it.  It will be a lot more PAR than the T5HO however is it 2x, 3x more.  That is something to test.

The PAR meter with smaller point sources like LEDs could also enable the user to get the ideal spacing and positioning to get maximum overlapping of light and therefore reduce the W even further to achieve the spread.  It is a pretty interesting subject when you get into that level.

It is something I have an auto search on ebay for so if one comes up at a much lower price then I will get it.  They don't come up though.  For now I suffice in theorising and reading other people's readings etc on other forums.  Not highly accurate and you have to assume a lot of the detail that way.  Hands on is always much more accurate than second hand information, no matter how many parameters are given.

For those with money freely available this is what you are after:
http://omnima.co.uk/store/product.php?productid=16142

http://www.midlandreefs.co.uk/xcart/home.php?cat=269

AC


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## Themuleous (6 Oct 2010)

I can see a use for them with LED lighting as its such an unknown quantity at the moment and will take time for people to get used to it and before things like the number, lumen, type, etc become as 'standard' as T5's and T8's.

Sam


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## GreenNeedle (7 Oct 2010)

Just for you guys to see this sort of unit in action and also for you to see how such small things make a huge difference, here is a picture log of many PAR readings of the same tank from top, centre and bottom of the tank.  Notice how much a difference there is in the reading just by having the glass lid on!!!

The note how much PAR the MHs are supply.  Remember we are looking at ADA MHs being 50ish at substrate and 150ish at water surface!!!

http://www.omnima.co.uk/forums/index.php?showtopic=6

Also I was just wondering. We are talking Â£250 her for a Quantum Meter.  Is there enough interest for 25 members to buy a 'group' PAR meter and chip in Â£10 each?  Then we can ship it to each other and sort out a plan/rota/schedule, where all 25 get the meter for a couple of days at a time 2-3 times a year?

That will of course mean some unlucky souls are waiting after the lots are drawn   so if 10 people think Â£25 is a sound investment or multiples of 10 think so then we could have a much shorter lead time each 'cycle' of swaps.

We can draw up a 'fools guide' instruction sheet rather than the 'techy' one supplied with the unit.

Let me know if anyone is interested.  this would of course only be UK based people and definately seriously interested.   For something like this only those who trust theirselves to be able to look after the unit we;; and keep it safe  should respond.

For those who are interested in the figures but not enough to splurge Â£25 out you could make a donation.  After all we will be publishing all the results and will build up a UK database of lighting.  At the end of the day the majority have retail systems and therefore it can act as a buyer's guide too 

Might push the ~UK retailers (naming no names) to sort themselves out and get their lights working efficiently instead of aesthetically etc   On the plus side they can also use th PAR data instead of Lumens which is a bonus for all.

For those who have never seen the ADA setup test from barrreport.com here is the link.  Next time you want your 3 special letters on something consuming electricity consider if you are getting your money's worth. Is it worth getting a third of the light for the same amount of electricity as other brands?  Or should you be writing to the manufacturer and demanding they improve efficiency and use a third of the wattage instead.

After all my guess is that they have done these because their followers want a high light unit, yet the company's philosophy runs on low light so they make the highlight (W) inefficient to fool you.

I tend to chuckle when people are so 'proud' of their unit unaware of its wastage 

http://www.barrreport.com/showthread.ph ... ht+PAR+AFA

Andy


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## sanj (8 Oct 2010)

I have actually found the PAR meter to be usefull. It depends on your set up. I dont think most people in the planted hobby would have considered 432w of T5s over an 8ft long x 3ft wide tank to be alot of light, but actually I have to keep my units as high as they can be from the water surface...thats 18" and still im getting 30-50 micro moles at the substrate with only half the output at 216w!!  

Otherwise I would have considered that 432w was a sufficient amount of light (and not a lot) and my units would have only been 8-10" of the surface. Par readings at this level would have been over 100 at the substrate.

I agree though, its not an essential piece of equipment and only a few people even have them in the Reef hobby. However I think it saved me alot of potential problems. 

If you do want one, I would suggest the link that SuperColey/Andy posted. I tried from another advertised source and waited well over a month with poor communication and no meter.


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## plantbrain (8 Oct 2010)

The cost of such an Apogee meter amongst a group.................is really reasonsable, how much do you pay for a NO3 test kit?

10 pounds?

20-30 folks using a PAR meter, same cost...........

You are not going to use it that much, maybe a few days, and they are really easy to use.
Then you know and the light is not going to change much from there.
You will also have a good base line for estimating other similar tank set ups and brands in the UK.

Some might want to use the meter for measuring plant PAR exposure as the stem grows up, or measure the reflected light off the glass vs algae covered glass, or the bottom reflectance, or make depth PAR curves.
Many will just measure their bottom ranges over the area and the top of the water and the evenness.

Still, this stuff goes fast and it is easy to do.

UKAPS is a good sized group and there should be interest and enough community to purchase a meter and then measure and test, this will also help add content to the PFK articles you submit as well.

I suggest folks each sell 10-20 pounds worth of plants, then contribute to a meter.
This way it's all "plant money".

Several clubs did this in the USA.

Helped many folks out.

Regards, 
Tom Barr


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## Garuf (8 Oct 2010)

I personally wouldn't mind chipping in or putting my name on a list to borrow one, I think I'm the most light paranoid person on here now I can't afford to upgrade!

*edited for spelling.


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## dw1305 (8 Oct 2010)

Hi all,
I'mtrying to persuade work that we need a proper PAR meter, it is a bit tricky because we already have one, but it is not portable and is designed for measuring PAR in a small chamber where you can place a single leaf (it does some other measurements to do with chlorophyll excitation and fluorescence).

For a lot of lamps you can get a pretty good idea of their efficiency from the many "grow your own" forums on the web, the growers of hydroponic "Tomatos" are usually pretty clued up about what gives you the most "bang for your buck".

A slight problem is that they aren't interested in the aesthetics of their growing plants so a lot of the lamps emit in the blue or red wavelengths. 

I'm interested in Supercoley's post (good post), do you know about any recent developments in the Sulphur plasma lamps?  I tried to get one for ages, but they were dogged by failure of the magnetron unit and I wasn't aware that they were still being developed commercially.

cheers Darrel


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## plantbrain (8 Oct 2010)

I've seen some at MBS(Plasma), they got good results but still in the R&D stages.
Be a few years, LED's etc will progress farther I think  unless something really radical is done elsewhere.

I can get a meter for about 250-300$ US, then ship as a gift.
Cost to ship is not much.
If you are going shell out 50-100$, might as well do a a group but and get something decent. 
I ran it in parallel with the LiCOR 193 and was no more than 1-2 micromols off over 2 meter's of depth in water usign a MH light.


Regards, 
Tom Barr


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## GreenNeedle (8 Oct 2010)

Tom has seen a plasma so thats more than me 

I heard about them but never seen them or heard any more.

However look how quickly TVs have gone from increasing in sizes and from Plasma to LCD to LED.  LED TVs just suddenly appeared from nowhere. and when it appeared LCD had only just become the norm.

So with the plasma lighting I would guess it will be silence and then all of a sudden............ bang.  Its here, the newest coolest must have lighting etc 

AC


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## Garuf (9 Oct 2010)

I understand that an aquarist in leeds is using a plasma rig they built themselves on a reef and it's working great but astronomically expensive to put together, the guy I was talking to in paws for thought seemed to think it was the next big thing, glitter lines better than the sun, best coral extensions and growth ever, phrases like that being bounced about. It seems to be the opinion on some reefer forums that it's a bit like minidisk, great, but too late though, especially as they don't yet have the versatility of led and can't be turned back on within a few minutes like you can with LED. They do however pack a lot more visible light for similar levels of par...


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## SteveyG (8 Nov 2010)

Is anyone still interested in going ahead with buying a PAR meter?

I'd be really interested to know the light levels of my new setup. The LEDs look dimmer than I'd hoped for despite them being blindingly bright.



			
				SuperColey1 said:
			
		

> However look how quickly TVs have gone from increasing in sizes and from Plasma to LCD to LED.  LED TVs just suddenly appeared from nowhere. and when it appeared LCD had only just become the norm.



They still are LCD TVs, just backlit by LEDs instead of CCFLs.


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## Palm Tree (10 Oct 2013)

dw1305 said:


> For a lot of lamps you can get a pretty good idea of their efficiency from the many "grow your own" forums on the web, the growers of hydroponic "Tomatos" are usually pretty clued up about what gives you the most "bang for your buck".


I have been looking around a few of those forums and it shocked me how they rate lighting, everything is about lumens. They say HPS and MH bulbs are better than fluorescent and their reasoning is that they throw out more lumens, but surely par is a better measurement than lumens?


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## dw1305 (10 Oct 2013)

Hi all,


Palm Tree said:


> They say HPS and MH bulbs are better than fluorescent and their reasoning is that they throw out more lumens, but surely par is a better measurement than lumens?


 PAR, or even better PUR, are much better readings than lux.

The growers of "Tomatoes" don't care about the cost of the electric (might I suggest that a lot of them aren't paying for theirs), lamp type, lumens or PAR, they go purely on how much, and how quickly their "Tomatoes" grow, and how much "lycopene*" they contain. If they are still using HPS lamps, by definition they are the ones that are producing the most PAR, they don't need a meter. That is also why they are changing their lamps every 6 months or so, again they don't need to know about lamp lumen depreciation, or anything else.

* substitute an anagram of CHT for lycopene. This is how the Dutch growers bred for high lycopene content, they smoked the plants and then bred from the most "laid back" ones. After a while the lycopene content became so high that you could smell it in the growing plant and select that way, leading to names like "skunk" etc.

cheers Darrel


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