Lighting an Aquarium with PAR instead of Watts

[madness]

Originally Posted by assasin6547

Quick question, would a Finnex LED 12" be "high" light for a 7.5 gallon 12x12x12 Mr aqua cube? Is that good enough to grow HC, DHG, Riccia and needle leaf ludwigia?

Thanks

If I read the charts correctly I think that you will be around 50mmol in a 12" cube tank if you use the Ray 2. Maybe down to 40 or so depending upon the details of the 12" version of the fixture.

That borders on high light. Depending upon who you ask it should grow just about everything. Might be pushing the edge of where you need to run CO2 though.

[hcdcharts]

Hello All,

What a great thread. I have a question concerning the AH Supply T5HO Bright Lights they sell with their reflectors. On Hoppy's chart he refers to their PC fixtures and reflectors and PAR readings but no mention of their T5HO lights. I'm sure Hoppy has better things to do than test every fixture on the market....so I have 2 48" T5HO of those lights w/reflectors over a 90 gallon about 24" above the substrate and about 8" apart. I am looking for the high end of medium light. I use CO2, I just do not want to go crazy with it as I use Excel. Is this enough light or not? Are these lights on par with Catalina's line?

[Hoppy]

Originally Posted by hcdcharts

Hello All,

What a great thread. I have a question concerning the AH Supply T5HO Bright Lights they sell with their reflectors. On Hoppy's chart he refers to their PC fixtures and reflectors and PAR readings but no mention of their T5HO lights. I'm sure Hoppy has better things to do than test every fixture on the market....so I have 2 48" T5HO of those lights w/reflectors over a 90 gallon about 24" above the substrate and about 8" apart. I am looking for the high end of medium light. I use CO2, I just do not want to go crazy with it as I use Excel. Is this enough light or not? Are these lights on par with Catalina's line?

Someone with access to a PAR meter needs to do some testing to be sure how good those AH Supply T5HO lights are. Based on their reflector design I suspect they are comparable to the Tek or ATI lights, as far as PAR is concerned. So, I suspect each bulb would give you around 25 micromols of PAR at that distance. With the bulbs spaced 8 inches apart you would possibly get almost twice as much PAR with 2 bulbs, possibly a little less. Maybe 40-50 micromols of PAR or medium light.

[hcdcharts]

Thanks Hoppy, that helps a great deal!!

[Jeffww]

I have a rather long 5g tank with two cfls suspended 15"above the substrate. The lighting is 2x26w in two 8.5" dome reflectors. The bulbs stick out maybe 3/4". Is this too much light? I'm kind of confused because the PAR graph says much over 100PAR which seems like a crazy amount if 50 is already "high light". Even reducing to 13w bulbs doesn't seem to be much different. In fact, I think they might be MORE light since they would be completely contained within the dome. I do have pressurized co2 though...However this is more PAR than what was on my 60p with 2x24w T5HO!

What's your opinion?

[Hoppy]

We had difficulties when trying to get repeatable PAR readings with those 8.5 inch diameter reflectors with CFL bulbs. There are just too many variables, including the actual physical size of the bulbs, which varies with manufacturer. I keep thinking I will go back and work on this again, but I haven't done so. I can't figure out a way to get data that will work for a variety of reflectors, bulbs, manufacturers, etc. I hope someone else will work on this.

[Jeffww]

Do you think that there's a high likelihood that I have too much light? I'm getting stunting in my R. rotundifolia of all things.

[Hoppy]

Originally Posted by Jeffww

Do you think that there's a high likelihood that I have too much light? I'm getting stunting in my R. rotundifolia of all things.

Intuitively only, I think you probably have high light, but I don't see that stunting any plants. Any stunting would be from a shortage of a nutrient, probably CO2. With high light you do need a lot of dissolved CO2 in the water to enable the plants to grow as fast as the light is driving them to grow.

[herns]

Any stunting would be from a shortage of a nutrient, probably CO2. With high light you do need a lot of dissolved CO2 in the water to enable the plants to grow as fast as the light is driving them to grow.

Does cutting back lighting period somehow helps stunting growth? Assuming CO2 is up to optimum level but light is just high.

Good info. Thanks for putting this up.

[xmas_one]

Just pulled a read with the mrgreen meter, two 70w mh jbj vipers on a 90gal 24*24*36 = 50 par @ 24" deep.

[newbieplanter]

I still have no idea what any of this means so be prepaid for questions when I start my new 55+!!!!!!!!!

[latchdan]

Can this be made a sticky already :P

[veryzer]

Hoppy, you said somewhere that one can grow pretty much anything with 50-60 par (I think that's accurate...can't find the source material). Does this include red plants? I'm running with about 75 par right now and am thinking of venturing into these more difficult species. Anyone else with first hand experience feel free to chime in.

Thanks

[Hoppy]

Growing plants doesn't take more than 40-60 PAR, with good CO2, but many of the plants that looks so good when they have red leaves do need better conditions than just that PAR and CO2. It seems that some need light that encourages the red leaves, and all need light with enough red in it to be able to reflect red so you see the color. That isn't true of all red leaf plants, but it seems to be true of some or even many. I will let some one else describe what it takes for that type of plant to look its best.

[veryzer]

"It seems that some need light that encourages the red leaves, and all need light with enough red in it to be able to reflect red so you see the color."

Yeah, I've heard the same. That seems to be the gripe about finnex and other leds. I have led fixtures with 20% 660nm. I guess the only way to find out is give it a try.

Thanks.