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Discussion Starter · #1 ·
Ok so after tons of research about lighting a planted tank, I've come to realize that PAR is the only meaningful measurement. However, that requires a PAR meter, and I don't see myself investing in one of those for quite a while...

So, I found this site HOW TO Calculate your tank lighting ? Fishtanktv

I did the calculations and this article says I have "very low light" (assuming my math is right).

Can someone help me with this?

I have a low tech, Walstad-ish 75g long tank (48"x18"x20") and just went out and bought four 23w (100w equivalent, 1600 Lumans, 6500k) CFLs. My hood is custom made and has the fixtures already installed so buying a tube isn't an option atm.

Surely there's a way to figure out a rough idea without buying a PAR meter...right?

Included is a picture of my tank with the four CFLs for reference.
 

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The second sentence is why that method is useless
This method does NOT account for reflection, refraction, absorption, type of light source, reflectors of fixture.....
I stopped reading there.

23 watt CFLs are powerful, but it all depends on how you have them mounted, what type of reflector you have, and the distance between the lights and the substrate.

Mounted sideways with no reflector would indeed be very low light. Mounted vertical in an aluminum dome reflector, like those clamp on work lights, would be upper medium to high light - at least directly underneath each bulb.
 

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Discussion Starter · #3 ·
Thank you for the reply. They're mounted horizontally unfortunately and I used some aluminum foil on the top of the hood as a "reflector".

To my eye, it seems pretty bright, but i also know that what I see doesn't translate to what plants use.
 

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Aluminum foil is better than nothing, but yeah you are most likely in the lower ranges.

Still should be enough for the plants you have, any slow growers like ferns, anubias, and swords and crypts possibly. The bacopa and whatever stem is on the left may or may not do well, just have to watch and wait.

Btw it looks like you have the java ferns planted too deep. The rhizomes need to be left exposed and not buried. Best to but those on a piece of wood or rock. But if you must plant them, bury the roots only, same for anubias species.
 

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Discussion Starter · #5 ·
Aluminum foil is better than nothing, but yeah you are most likely in the lower ranges.

Still should be enough for the plants you have, any slow growers like ferns, anubias, and swords and crypts possibly. The bacopa and whatever stem is on the left may or may not do well, just have to watch and wait.

Btw it looks like you have the java ferns planted too deep. The rhizomes need to be left exposed and not buried. Best to but those on a piece of wood or rock. But if you must plant them, bury the roots only, same for anubias species.
Thanks! I'll pull them up a bit right now!

One more question:

Can i increase the amount of time the lights are on instead of increase the lighting? I've got them running 4.5 hours in the morning, 7.5 hours off, 4.5 hours at night and 8 hours off overnight (we both work 12hr shifts)
 

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Thanks! I'll pull them up a bit right now!

One more question:

Can i increase the amount of time the lights are on instead of increase the lighting? I've got them running 4.5 hours in the morning, 7.5 hours off, 4.5 hours at night and 8 hours off overnight (we both work 12hr shifts)
It is my knowledge thanks to this forum that it is not so much the duration of your photoperiod but more the light intensity. Having your lights on for longer will just promote algae growth instead of plant growth.
 

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Discussion Starter · #7 ·
Well, i believe the "siesta" time period is to rebuild CO2 levels, but mine seems to be pretty long compared to others that I've researched. It's just the hours we're home and able to enjoy it
 

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The second sentence is why that method is useless

I stopped reading there.

23 watt CFLs are powerful, but it all depends on how you have them mounted, what type of reflector you have, and the distance between the lights and the substrate.

Mounted sideways with no reflector would indeed be very low light. Mounted vertical in an aluminum dome reflector, like those clamp on work lights, would be upper medium to high light - at least directly underneath each bulb.
I seem to be confused on this whole aspect here in a way. Ill show you guys some examples of what I am talking about here with my tanks later on when my lights come on.

But to kind of give a summery the best I can, what I got going on is algae actually growing (diatoms) like 7 inches down from the water surface. Like its clear as day on the glass and its a straight line around the tank where its growing. I mean this is kind of fascinating how it seems to work. So I would almost assume that is how my reflectors start to hit the sides of the tank at that depth.

I have the typical metal 10 inch covers.... 4x CFLs ( 23w ) on a 120 gallon tank. I believe with how high I have the lights up, its a total of 26 inches from the bottom of the reflector to the sand bottom.

I was running 4x 40w cfls ( I think those are the 150W equivalent ) but started to assume that was way too much light for a normal ferts with non co2 tank... granted I use glut in it, but still nothing is better than co2 injection.

Honestly I have no idea what I going on right now. I mean I should have enough light, but even still think I might have a bit too much.
 

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This article cleared up the mystery for me. Towards the bottom it gives the type of bulbs used, the watts/gallon, best bulbs available.

http://www.americanaquariumproducts.com/Aquarium_Lighting.html

I went with the newer T2 spiral CFL's, 23 watt, 6500k, 1600 lumens. I am mounting 8 of theses inside a box lined with foil or mylar if I can find some.

I got 40g Bow front tank, 20 inch depth.
 

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Discussion Starter · #10 ·
This article cleared up the mystery for me. Towards the bottom it gives the type of bulbs used, the watts/gallon, best bulbs available.

Aquarium Lighting Information Guide | Reef Planted | PAR PUR/PAS

I went with the newer T2 spiral CFL's, 23 watt, 6500k, 1600 lumens. I am mounting 8 of theses inside a box lined with foil or mylar if I can find some.

I got 40g Bow front tank, 20 inch depth.
Wow. I can't believe I read all of that. Great article. I'll save it for later
 

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Personally speaking, there is a tad bit of marketing in that article, and a few non-critical but a bit misleading.
It would take more time and effert to dispute it than I care to give at this point.
 
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Well, i believe the "siesta" time period is to rebuild CO2 levels, but mine seems to be pretty long compared to others that I've researched. It's just the hours we're home and able to enjoy it

You could certainly use a "siesta time" for that. I typically see it being used to inhibit algae growth. Algae has a problem with 2 light periods, plants don't.
 

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Personally speaking, there is a tad bit of marketing in that article, and a few non-critical but a bit misleading.
It would take more time and effert to dispute it than I care to give at this point.
I agree there is some marketing but there is also some good information if you read past the marketing. My interest was economics, what was the best bulbs I could by at the most economical price. The SHO t2 bulbs look attractive, but at $35-40 a bulb, meh. I got 8 of the 1600 lumen, 6500k bulbs for $28. 8 sockets at $1.49 and a pack of connectors and a switch for $4.50, now just to put it together before my plants die off.
 

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You can double the light from each of those horizontal bulbs by getting some thin aluminum flashing material from the hardware store and making individual reflectors for each bulb, shaped like \_/, a trough with the bulb in middle. Bend the flaps so you can see a full reflection of each bulb on each side of the bulb. You don't need to spend much time polishing the aluminum - it is a good reflector as is.
 

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You can double the light from each of those horizontal bulbs by getting some thin aluminum flashing material from the hardware store and making individual reflectors for each bulb, shaped like \_/, a trough with the bulb in middle. Bend the flaps so you can see a full reflection of each bulb on each side of the bulb. You don't need to spend much time polishing the aluminum - it is a good reflector as is.

That was my thinking as well. Family dollar sells Polished stainless steel bowls for $1 a piece. I've used them in the past as a heat shield for distilling phenols and ammonia.
 
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