Walstad low-tech 40 B, central FL biotope, creator of Jordanella floridae x Mobula birostris hybrid
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36 Posts
Hello all,
I'm getting back into the hobby with a new project, and need advice on lighting.
The setup: 40 Breeder tank, going to be a Walstad low-tech planted, no filter/no ferts/no CO2 (I'm another willing victim of Foo The Flowerhorn...) I have bought & read Ms. W's excellent book. It will be an East Central FL (Space Coast / upper St. John's River) biotope, using only locally-collected plants, fish, wood, etc. I'm seeking small, native inhabitants like flagfish, topminnows, mollies, pygmy sunfish, grass shrimp, snails, tadpoles, etc. I don't yet know what species of plants I'll have beyond "the local ones"
I'm starting bottle tests on substrate shortly.
I decided to try to DIY everything but the tank itself, partly due to a tight budget, but mostly just to learn, be creative, and make things like I want them.
Building the stand went well, but the next leg of the journey... the lights... has proved to be quite frustrating thus far. I know how to make basic electronic stuff, but after 3 design cycles of sketching things up, sourcing parts, etc., something was still just not seeming right.
The lightbulb finally came on (groan...) when I realized lots of folks were reporting growing lots of plants with cheap, low-lumen LED lights. It seems I may have made some bad assumptions about how much light I really need, which is where I need help.
The info I gathered said that "low", "medium", and "high" LED lighting is calculated at 15, 30, and 60 lumens/liter respectively. For 40 gallons (151 liters) that totals 2265, 4530, and 9060 lumens. (Tank height is 16 inches and I have a glass lid, BTW.) I also found a seemingly knowledgeable source using 50 lm/L for "medium high" light, which totals 7550 lumens.
My understanding is that "high" light needs CO2 injection, which I have no interest in.
Thus, a "medium high" (7550 lumen) design with a dimmer seemed like a good idea for a versatile light. I can do that with about $50 in parts, but it's wasted money if it will only ever be running at a fraction of that brightness in reality.
I know it's all complicated by not knowing the plants yet, and by using lumens instead of actual PAR values, but... around how many lumens do I realistically need my light to have? Sure, you can build a 12,160 lumen, 6500K/2700K combo light for about $60. But if I actually only need a few hundred or couple thousand lumens, that's a significant cost savings in parts and electricity.
Also, will plants be happy with 60% of their light from 6500K white LEDs and 40% from 2700K (to get more red)? Is it worth adding significant additional cost to include pure red or blue LEDs on top of that?
Any advice or opinions are most welcome. Thanks!
I'm getting back into the hobby with a new project, and need advice on lighting.
The setup: 40 Breeder tank, going to be a Walstad low-tech planted, no filter/no ferts/no CO2 (I'm another willing victim of Foo The Flowerhorn...) I have bought & read Ms. W's excellent book. It will be an East Central FL (Space Coast / upper St. John's River) biotope, using only locally-collected plants, fish, wood, etc. I'm seeking small, native inhabitants like flagfish, topminnows, mollies, pygmy sunfish, grass shrimp, snails, tadpoles, etc. I don't yet know what species of plants I'll have beyond "the local ones"
I decided to try to DIY everything but the tank itself, partly due to a tight budget, but mostly just to learn, be creative, and make things like I want them.
Building the stand went well, but the next leg of the journey... the lights... has proved to be quite frustrating thus far. I know how to make basic electronic stuff, but after 3 design cycles of sketching things up, sourcing parts, etc., something was still just not seeming right.
The lightbulb finally came on (groan...) when I realized lots of folks were reporting growing lots of plants with cheap, low-lumen LED lights. It seems I may have made some bad assumptions about how much light I really need, which is where I need help.
The info I gathered said that "low", "medium", and "high" LED lighting is calculated at 15, 30, and 60 lumens/liter respectively. For 40 gallons (151 liters) that totals 2265, 4530, and 9060 lumens. (Tank height is 16 inches and I have a glass lid, BTW.) I also found a seemingly knowledgeable source using 50 lm/L for "medium high" light, which totals 7550 lumens.
My understanding is that "high" light needs CO2 injection, which I have no interest in.
Thus, a "medium high" (7550 lumen) design with a dimmer seemed like a good idea for a versatile light. I can do that with about $50 in parts, but it's wasted money if it will only ever be running at a fraction of that brightness in reality.
I know it's all complicated by not knowing the plants yet, and by using lumens instead of actual PAR values, but... around how many lumens do I realistically need my light to have? Sure, you can build a 12,160 lumen, 6500K/2700K combo light for about $60. But if I actually only need a few hundred or couple thousand lumens, that's a significant cost savings in parts and electricity.
Also, will plants be happy with 60% of their light from 6500K white LEDs and 40% from 2700K (to get more red)? Is it worth adding significant additional cost to include pure red or blue LEDs on top of that?
Any advice or opinions are most welcome. Thanks!