Time vs Wattage

[egruttum]

I run a low tech tank and plan to continue low tech for the foreseeable future.  I am only using low light plants as well.  With aquarium lighting for plants I assume there is a balancing point between duration of daily light and strength/wattage/amount of light.  For example can you use really bright lights for a short amount of time and get the same growth as using less powerful lights for longer duration?  Obviously there has to be a point where the light is too dim to do anything but lets assume we don't get that low.  I'm guessing that with a low tech tank the limiting factor for growth is CO2 so running less light for a longer duration allows the plants more time to absorb the limited amount of CO2 that gets dissolved into the water?  Or am I over thinking this?  The reason I ask is the engineer in me wants to build my own lights from LED SMDs and I am trying to balance wattage and number of SMDs.

Edited February 20, 2021 by egruttum
Added specific comment on low light plants.

[Koi]

You pretty much hit it on the money as far how to balance the lighting.

22 minutes ago, egruttum said:

Obviously there has to be a point where the light is too dim to do anything

You would be surprised how little light some plants need

I'm using kind of a custom LED for my tank also and that plants seem to be doing ok. I bought these 3500k industrial/commercial leds that look like its for some kind of shelving unit and wired two together. The only thing I hate is that is has a orangish hue but for 20 bucks per luminaire I can't complain.

I just wanted to throw this question out there because it seems like you know a lot about LEDS. If possible I wanted to see if you had any recommendations for led strips or know a decent place online I could look around. I've been looking for either decent 5050 or 5750 strips. I've had my eye on the Phillips smart strips and Ive tried to see if Cree made any but I wanted to see if there were any other good

brands with an economical price.

[Daniel]

What you are asking is similar to the concept of 'degree days' with gardens and agriculture crops.

There is an additional dimension to your question that needs to be considered. The additional dimension is that there isn't an overall category of 'aquarium plants'. Aquarium plants have a wide spectrum of lighting and nutritional needs.

Typically that spectrum in regards to lighting is for convenience broken into 3 categories. High light plants, medium light plants, and low light plants. So a long period (or even a short period) of low light might be fine for a low light plant, but there would never be enough intensity for medium and high light plants no matter how long the period was.

 CO2  is not typically the limiting factor. What is limiting typically is the period of the light and the intensity depending the the kinds of plants you are trying to grow. Eventually CO2 does become a limiting factor but it is only the tail and not the dog.

And speaking of spectrum, the photosynthetically active part of the lights you are using is more important than overall lumens. Photosynthesis is driven by light in the blue and the red part of the spectrum and not by what is in between. The result is a purplish light that most people find unattractive. The solution is to add back green, which is useless to the plants, but makes the overall light appear more whitish to humans.

[Koi]

19 minutes ago, Daniel said:

So a long period (or even a short period) of low light might be fine for a low light plant, but there would never be enough intensity for medium and high light plants no matter how long the period was.

Now that I think about it I agree, I may have overgeneralized a little.

I was assuming if one was to spend the time to build LEDs they wouldn't go low lighting(my idea of low lighting are T12s). But I still think extending photoperiod on medium level lights can help with achieving a "high light" look i.e. bringing out reds/carpeting 

But maybe this is all from me misunderstanding why kind of light level I have. I personally don't know what is considered low light, medium light and high light so most times I'll measure by light duration.

[Daniel]

@Koi I pretty sure my understanding is lacking also. What I do know is that are multiple factors that are hard to reduce into 'A' vs. 'B'. That is why is something like a Fluval 3.0 (or similar) is nice. You can adjust the intensity of different parts of the spectrum as well as the period depend on what kind of plants you have and your goals.

@Streetwise and @Bentley Pascoe have lots to say on this.

The LED lights I personally own that I like the best are Kessil a360x's.

[Koi]

37 minutes ago, Daniel said:

I pretty sure my understanding is lacking also.

You coulda fooled me man haha.

I always felt that a bigger mistake was people confusing color temperature with spectrum. I'm not sure if I'm saying that right? Basically what I mean is as far as I can understand color temperature is how we perceive the light but I always see tons of websites that the kelvin rating will affect growth.

You know I think the Fluval 3.0 is super cool but I feel like with all the choices I'll either have option paralysis or I'll throw my tank off balance every 2 weeks playing with the settings. Now the Kessil... thats a classy light I'm super jealous

[egruttum]

Thanks for the responses.  When I said low tech I also meant low light plants, sorry for leaving out that piece.  I guess I equate low tech to low light as well.  My mistake.

The LEDs I have coming are full spectrum white lights.  My first attempt will be with LED COBs so I don't have to mess around with power supplies and LED constant current drivers.  I didn't purchase them from Amazon but if you look for "DynaSquare - 12V LED Light Engine - 5000K Grow Lights" Amazon has them (forum rules appear to allow Amazon links).  I am going to try these in a nano aquarium first for fun.  I think my biggest problem will be keeping them working with the moisture in the hood.  But that's the fun with playing with low voltage and relatively low price items, if they fail not the end of the world.

From looking at these forums and pictures I realize that I am in the small minority but I like the look of a black hood on my rimmed aquarium.  To me this is the classic aquarium look and I don't have a desire to go rimless with hoodless lights on top.  Hence why I am trying to build my own.  Again, if I fail, no big deal.

 

[egruttum]

1 hour ago, Koi said:

people confusing color temperature with spectrum

You are absolutely correct on this.  Color temp and spectrum are independent items.  The eye pleasing temperature may do little to keep your plants healthy.  Especially since some LEDs use a phosphor coating to make the color temperatures and that doesn't necessarily give the correct spectrum.

I'm sure I will eventually see the light and purchase a great aquarium light.  But for now I am having fun playing around.

As for the question on LED strips I haven't paid much attention to them because I am just working to build my own.  Unless you purchase sealed ones made for an aquarium I think you will face what I am expecting to face trying to moisture-proof LEDs while still removing heat.  Good luck.

Edited February 20, 2021 by egruttum

[Koi]

19 minutes ago, egruttum said:

To me this is the classic aquarium look and I don't have a desire to go rimless with hoodless lights on top.

Wait till you get a look at this hunk of junk

I guarded one side when obviously I should have done both haha

[egruttum]

5 minutes ago, Koi said:

Wait till you get a look at this hunk of junk

I'm all about function over form.  If it works it works. 

I am using the light the came in the aquarium kit for my first planted tank.  It seems to work for now.  The tank needs some trimming and replanting but I am waiting for my AC sponge filters to arrive.  With the weather and the USPS being behind no idea when they will get here.  They were shipped same day (Thanks Aquarium Coop) but the mail has them really delayed.  Hopefully Monday so I can clean it up. 

[Koi]

1 hour ago, egruttum said:

I am using the light the came in the aquarium kit for my first planted tank.  It seems to work for now.

Your light is working great. I’ll give more credit to you though, the tank looks super healthy!

[gardenman]

I've used everything in the way of lower cost aquarium lighting at one time or another. The first aquarium lights were the simple metal ones with the long incandescent bulbs. (I dusted one off a while back and used the screw in LED daylight bulbs, but the bulb life was pretty short in that fixture. Likely due to the heat trapped in the fixture.) Then we transitioned to fluorescent bulbs, T-12, T-8, and ultimately T-5. Much better, but you only get a year or so from the tubes. Now LED. I've made my own using LED strips. With the waterproof kind the waterproof coating tends to discolor rather badly over time and dims the lights, so I gave up on them. The non-waterproof kind worked better. Both types tended to go through power supplies rather quickly. I'd get a year, maybe two before the power supply would give up. I've now switched to lower cost options. I like the T-5 shaped shop lights a lot. The 6500 K ones are pretty great. You can daisy chain them together and they seem to last a while. The lower cost "LED aquarium lights" were okay, but I really like the Nicrew SkyLED Plus light. It's pretty cheap, gives a lot of light for a relatively small amount of money, and the plants seem happy with it.

I've grown house plants, aquarium plants, orchids, and more under lights for probably fifty years now. I'm using some "real" LED grow lights now on my seedlings with the purple (red/blue) lighting and the geranium and lobelia seedlings are loving them. They're giving the best growth I've ever gotten under lights for terrestrial plants. I snuck a dish of floaters under them to see how they'd do and they're not as happy as the seedlings are oddly enough. That could be a nutrient issue though more than lighting. 

Based on my experience, I wouldn't bother too much with making your own lighting except for as a hobby. The cost/return just isn't there these days when you look at something like the Nicrew SkyLED Plus. or the T-5 shaped shop lights and what you get for the money.  Once my seedlings move outdoors (sometime in May) I'll slide a clear Sterilite container under the red/blue LEDs and see how aquarium plants grow under them. It could be a neat way to increase your plant count.

[egruttum]

Thanks gardenman.  Nice to have your long perspective as the technology changed.  My playing around is a fun hobby, just trying to see what i can make myself.  I'm sure in the long run (probably the short run too) just buying a commercial light is the best way to go.  But then what do I have to complain about when things fail?

Good luck with your seedlings.  I am trying to rescue an azalea from before Christmas with some homemade LED stuff.  My office looks like a grow room from the outside so I'm waiting for a neighbor to ask questions.  But the azalea has started flowering again so I'm doing something right (or wrong.  But I wanted to flower again so I'm going to say right).  Anyways, good luck with your flowers.  I'm happy to see at least one person is confident that spring is coming.

 

[gardenman]

23 hours ago, egruttum said:

Thanks gardenman.  Nice to have your long perspective as the technology changed.  My playing around is a fun hobby, just trying to see what i can make myself.  I'm sure in the long run (probably the short run too) just buying a commercial light is the best way to go.  But then what do I have to complain about when things fail?

Good luck with your seedlings.  I am trying to rescue an azalea from before Christmas with some homemade LED stuff.  My office looks like a grow room from the outside so I'm waiting for a neighbor to ask questions.  But the azalea has started flowering again so I'm doing something right (or wrong.  But I wanted to flower again so I'm going to say right).  Anyways, good luck with your flowers.  I'm happy to see at least one person is confident that spring is coming.

 

Spring will be here before you know it. I'm in snowy NJ right now, but my daffodils are a couple of inches out of the ground. They'll start flowering in a few weeks. The most-protected ones anyway. From mid-March on the threat of snow needing shoveling largely disappears. I divide the year into two halves instead of four seasons, the warming half and the cooling half. My daily average temperature bottoms out around January 21st then starts to slowly rise until July 21st when it tops out and starts to decline again. Despite all of the ice, snow and cold, we're now a full month plus into the warming half of the year. That helps me mentally cope with winter. The days are getting longer now, average temps are increasing each day. In another month we'll be two full months into the warming up cycle and the world will look a lot different than it does now. I typically start mowing my grass in the second half of March. A month after that and spring will be in full display with lots of flowers and plants up and growing. In May the threat of frost disappears and the gardening season is in full swing. Then when the brutal heat gets too much, from July 21st on I can tell myself we're in the cooling off half of the year and it'll keep getting better each day. It's a psychological game I play with myself, but it works.