|11-25-2014 03:59 PM|
no pun intended, I have seen the light--the watts/gal always struck me as utterly bogus---anyone who completed G12 physics knows energy intensity decreases by the inverse square of the distance--- and from this brilliant post, I can see I am growing algae b/c I have a PAR of 50 at the bottom on my 65G freshwater tank... and no co2...either hanging the lights and adding CO2.
|11-25-2014 08:05 AM|
Only if your using power compact bulbs.
Mostly reef folks still using these bulbs which I actually quite like.
Anyone who believes PAR is a fad,is doomed from the outset in their effort's at growing healthy plant's.
More likely to experience spectacular algae growth with too much PAR and limited ability to supplement CO2 .
Hardly anynbody's effort's are thwarted by too little light/PAR.
The PAR values of a particular bulb or bulb's,are much more critical than color spectrum.
Most agree on this.
|11-24-2014 10:52 PM|
|candymancan||It is a fad but people constantly bash PC lights yet no one cares to measure them if you rely on PAR so much wouldn't it be fair to properly measure PC's and not just T5 lights|
|11-24-2014 11:33 AM|
I used the bulbs you mentioned both over my 55 gal and also my 80 gallon for a couple year's.
65 watt Straight pin PC bulbs mounted end to end in 48 inch fixture
bulbs are 22 inches long.
Also used 55 watt PC bulbs also 22 inches in same 48 inch fixture.
Was a bit much for low tech,NON CO2 and window screen was used to partially decrease intensity.
Didn't /couldn't use more light for low tech on my tanks.
I used the 48 inch PC fixture with mirror type reflector for it was layin around from salt water tanks that I used to dabble in ,and so no added expense for new fixture to grow weeds.
Earlier in this thread you say PAR is relied on too much,Is a fad, but yet you want someone to measure the PAR for PC bulbs you mention.?LOL
Title of this thread "Lighting a tank with PAR as opposed to watt's" is for now,, all most need to know when trying to discern what lighting might place one in high,medium,low light regions and thereby suggest where CO2 or lack thereof may be elephant in the room with respect to healthy plant growth.
|11-24-2014 08:53 AM|
A 54 watt T5HO is a 48 inch tube the 55w PC is around 20 inches.. Youre right it would take 2 PC lined up horizontally to light a 55g.. but why would you do that when you can get a 96w 48 inch PC and have greater light then a single 54w T5HO or 2 lined up 55-65w PC bulbs lol ?? You guys aren't making any sense here.
I really wish someone would measure the Par of PC bulbs... 36w-55-65-96w
|11-24-2014 06:12 AM|
One way T5HO bulbs have an edge over PC bulbs is that you can design a reflector that greatly increases the light that reaches the aquarium substrate because it is a linear bulb. But, a PC bulb, being a bulb consisting of two very closely spaced tubes, doesn't allow for an equally effective reflector. A lot of the light emitted by a PC bulb can't be directed down into an aquarium.
A 55 watt PC bulb can be compared to a 54 watt T5HO bulb - equal wattage, and the tube length is about the same also. But it takes two of the PC bulbs to light a 48 inch long tank, and only one T5HO bulb. Even if both give the same PAR reading at the substrate, it takes twice the wattage of PC bulbs to get that PAR. I believe the T5HO bulb, with a good reflector gives more PAR than the two PC bulbs with a good reflector.
|11-24-2014 04:37 AM|
On a side note.. you can (both real world and theoretically) overdrive 2 18" t5's to equal a 65w PC.. Does that translate to equal lumens..???? Probably not.
Point is the PC's ARE specially designed compact flourescents that can handle high power loads in a smaller package natively... but again w/w they are no better than "good" t5's.. only smaller...
The TERM efficient in this case has more than one way to look at it.......
As a summary of my "thinking" .. Yes some PC could definitely be underestimated as to PAR, PC's have a high density per inch, watt efficiency is equal to most other good flourescents, and falling behind LED's (for fun) AND as a food for thought (and seeing that spectral chart) my personal belief that high "near UV" will help "color" red plants..something a bit lacking in LED's or lower output/different spectrum bulbs (again for fun)...
|11-24-2014 04:09 AM|
|candymancan||Im going by the size of the tubes.. That was the main advertisement with PC's when they were introduced they were more efficient then T5's in respect to there size. No one puts a 65w 22 inch PC on a 55-75g tank.. So to compare sizes you need go to the equal length PC and that would be the 96 watt one. Its double the wattage of a T5HO that's 48 inches... sure that's obvious... but its lumen output is nearly double as well. A 21 inch T5HO is only 24 watts.. Going by the lumens of the bulb... which range from 85 up and down.. But lets go by you 93. That's only 2200 lumens.. The PC puts out 5,100kaccording to your chart. That's almost triple the lumen output.|
|11-24-2014 03:57 AM|
47W GE is 4800 initial lumens w/ 4410 mean.. 93.8 L/W........ about the same as the PC...
Density per inch is another story.. Your PC is 44" effectively.. 3.6x 18" = 64"...
4-18" T5's 2 @10000k 2@ 6500k assuming equal phosphors to get those CCT's..is actually better than your PC............
|11-24-2014 03:39 AM|
a PC is way more efficient then a T5NO or a HO.. Im saying I had 2xT8 Floramax bulbs, and 2x T5 Normal Outputs 1 a plantgrow and 1 a daylight bulb I had 4 lights on the tank and this single PC is growing my plants better and 1 of the tubes is a 10k tube which isn't exactly ideal for plants. Yet according to your chart you linked my single PC shouldn't be able to grow my red plants like it is
Im not saying I have some great theory that's better then PAR all im saying is people rely too much on this stuff. Im by far no expert in lighting.. But based on my own experiences using PC lighting its a lot better then a T8 or T5 NO.. And similar length T5HO's its better
Also Per watt/ length of the bulbs PC is more efficient then a T5HO.. a 65W PC bulb is only like 22 inches long You cant compare a 65w PC bulb to a 54 watt T5HO because honestly... who is going to use a 22 inch PC over a 48 inch long 55G tank ???? I have the 65 watt ones over my pentagon that's 30 inches long and it barely lights the corners of the tank ... A similar wattage T5HO is what near 55 watts but it is like 48 inches. double the length. If you want to compare a T5HO to a PC light at least compare the bulbs of the same sizes, so if you want to go on a 55g tank a 48 inch PC light is going to be 96 watts.. Im pretty sure that bulb will have more Lumens then a T5HO.. Nearly double more lumens actually.. and most PC fixtures are duel fixtures.. That's nearly 200 watts... a duel T5HO will be what 110 watts ? What would the lumen output be for 2 T5HO's ? Around 10k ? And those 2 PC's would be what ? I b elieve the 96 watt bulbs are 84 Lumens per watt.. That's 8064x2 is 16128 lumens...
So you got a 55G tank.. One with 10k Lumen 2X T5HO and one 55g with 16k lumen duel PC... Honestly which would you chose ? Also the PC has better light choices.. being 2 bulbs in 1 you could get one as a 6700/10k combo and the other a plant grow combo and with that plantgrow combo it will be even better then the T5HO's... The T5's are stuck with 2 bulbs.. so you can have what a 6700k and a plantgrow ? Or a 6700/10k or what not.. Essentually with the PC you have 4 different bulb combo's and the T5's are stuck with 2.
Do you guys get what im getting at here ? And im talking with comparable reflector's.. The only problem with PC is they are hard to come by except for online... Heck even T5 bulbs are starting to disapear
|11-24-2014 03:24 AM|
Besides some spectral differences.. PC's are not more efficient than t5's..
4 (3.6) 18" t5's "should" give the same results as your pc..given the same spectrum..
Current states almost 100l/w.. I "assume" from their numberless chart..
BTW: their spectral charts make no sense.. showing heavy output from 300-400nm (you have to zoom in on the pdf).. BUT if real, it would explain low PAR numbers since light below 400nm is under-sampled..
|11-24-2014 02:35 AM|
|Hoppy||Candymancan, how would you advise someone on what specific light fixture to use on a specific tank, in order to get a a medium light intensity at the substrate in the middle of the tank? If you have an idea about how to do it with better accuracy, please post your idea here. However we do it today, in a few years it is likely that someone will find a better way to do it.|
|11-23-2014 08:10 PM|
Yes but the graph you showed im assuming you didn't make that one, still seems very biased towards PC lighting...
I guess it makes sense if you have no reflector lol but come on even the basic PC fixtures have metal reflectors. The one I have from Current its a duel 65w one. If you go back to page 22 a guy posted pics of his.. That's the one I have.. It doesn't have curved metal for each bulb so I can see how each bulb would wash the other out.. but its still a reflector and the sides are curved at least. I have thought about taking the reflector out myself and bending it in the middle to better reflect the light. I like those reflectors on that website you linked though.
But yea even with a crappy reflector or no reflector a PC light surely is better then any T8 light lol.. As an example I took an old T8 fixture you know those bulky ones with the white reflectors.. I gutted it of the the t8 stuff and I put a 65w PC ballast inside and I mounted the light directly inside the white reflector the t8 bulb used to sit in lol.. but 1 65w PC bulb is deff a lot stronger lighting then an 18W T8 lol. Its also better then my duel T5NO with a metal reflector .. My plants.. some of which are high light plants like Tiger Lotus and Red Combamba and red ludwigia and one I can never get the name right.. Lippphidurious or whatever its called lol.. They are all red/purple...
Ever since I replaced the duel T5NO's and that T8 (I had 4 lights over this tanks 2xt8 plant grow and the duel T5NO) with just this one PC light (6700/10k combo) my Red Ludwigia instead of being green with those 4 lights is now red.. and my Lipphidious plants instead of being only purple half way up the tank are now purple all the way near the bottom about 20 inches down (its a 27g hex about 25 inches tall)
So from my personal experience this single PC light using a white T8 lights reflector (heck 4 inches of the light isn't even in the reflector) is better then the 4 combined T8/T5NO lights I had. This pic is my ghetto PC in a T8 hood.. see the ends.. they aren't even in the reflector.. Plus the 10k on this light isn't exactly ideal for color spectrum... And yet look at my plants.. Since they are about 5-6 inches tall right now (I trimmed them).. According to your chart with my tank being 25 inches tall and my lights another 2-3 inches above that... subtract 6 inches.. my PAR should be like only 10 or so. Yet why are my medium/high light plants red ? I don't use CO2 either..
Sooo yea again like I said PAR is overrated... big time. That and your chart you linked is way off lol.. The one on this thread is more accurate if you go by PAR his chart with my 25 inch tall tank, lights 3 inches above minus the 6 inch growth of my plant my PAR with the PC light is about 34-40 which is around the medium light according to your chart and what he said.. Because if I went by your chart my PAR being at 10 trust me my plants in the pics would be green.. I have had them in really low light tanks and they just grow green.. But according to your char my part is really low light and yet they are very colorful .
|11-23-2014 01:10 PM|
As to 1) PAR meter accuracy.. I've stated and shown numerous times the "inaccuracies" of most meters..w/ the exception of a Li-Cor
2) Yes PAR measures (assume a li-cor for now) all light from about 400-700nm and treats each equally, which is not "exactly" correct based on the PUR idea...but it is relatively close..
IN general think of a progression from worse to better..
visual is worse than watts which lumens which is worse than lux which is worse than PAR which is worse than PUR which is worse than ind. measurements per species based on spectrum and quantum efficiency of a light......
any "economic" PAR meter has a terrible bias against light in the 660nm range and will under-sample it. It will also over-sample green and ect. each band having a corresponding inaccuracy..The 'hope" is w/ a full spectrum light that it averages out........ An "assumption"...........
Obviously "precision and accuracy are not at a "research" level.. and errors occur..
None should be taken as "scripture"...
Red line is approx how a Li-Cor measures light.....
As a side note T8's are marginally less efficient than a T5.. As to PC.. ???
I hear what you are saying in the fact that one shouldn't rely on any one measurement.. but one needs a starting point......
Even PUR is inaccurate based on an individual plant species..Since that "green line" is actually taken from an "average plant" response.. meaning an overall based on who knows what species..
speaking of PUR apparently there is one even better.......
good luck finding a PSR (or PUR) meter.. or a cheap way to measure it.......
Do we really need to go to that level??
|11-23-2014 06:43 AM|
I still don't think this PAR is correct... If this were true then having 1 T8 light or a Power compact light in a 25 inch tall tank apparently doesn't matter they both are low light... lol AIn fact this graph shows a PC light is almost identical to a single T8 light and that deff cant be true.. I've held a T8 6700 and a PC 6700 together and the PC is nearly double the brightness in the tank height tank. In fact I had 2 T8's and 2 T5NO over my 27g hexagon and replaced those 4 lights with 1 Power compact and my plants are still red and purple..
This is a Joke because I have some pretty strong reds and purples in some of my medium/high light plants using my Power Compact lighting.. And whats is AHS PC ?? What does the AHS stand for ?
This graph is basically saying the par from 1 T5HO is almost 50 at 25 inches and a PC light is like 2 or 3 par at 25 inches.. HAHAH ok lol... Has anyone actually measured a PC light with a reflector... these NO REFLECTOR graph are very biased... Why are you comparing individual T5HO reflectors with T8's and T5NO or PC light with no reflectors or white back grounds..
I haven't seen a T5NO use a white background.. The ones I've seen use reflectors, and my PC lights have reflectors on them... what company sells a PC light with no reflector. I've searched google for HOURS i cant find one person who has done measurments on PC lights with reflectors.. So until then that graph you posted above.. lol..
PAR is another FAD like watts per gallon.. It isn't accurate when measured in the proper 400-700nm range. PAR only measures the ACTIVE radiation output of a light... Not the usefull radiation PUR... That can be used.. so this is exactly another WPG fad that i wish would just go away.... You can have 2 6700k bulbs and 2 Plant grow bulbs.. those plant grows will outgrow those 6700k yet how can that be if the PAR is the same ? Because PAR isn't measuring the usefull lighting.. omg.. this is giving me a headache
Also your chart you post Jeffkrol and the ones posted on this sticky.. The measurements are WAYYYY off.. The ones he posted for T5HO's using like 15 different fixtures.. the average PAR at 25 inches for TWO bulbs is around 40-56 PAR And his chart for the PC lights.. using 1 36 or 55w BULB for 25 inches the par is 23.. So using a duel fixture for 2 bulbs the par is around 46. That's about the same as most of the T5HO light fixtures soo according to these charts a PC light near identical to a T5HO.. just depends on the reflector your T5HO has... Yet according to your chart PC bulbs are almost like T8's...
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