# LED advice needed for wastewater experiment



## gatorgrabber (Dec 30, 2016)

Greetings all! Hopefully you can help with a project we have ongoing since we really need adult supervision!

We are culturing both Azola and Salvinia for use in a wastewater project. Some details:

The tanks are 36" long by 18" wide by 6" deep. 
There are glass lids on the tanks.
Lights can be as close as 4" to the surface of the water.
I'm only interested in lighting that will make the plants happy!

Since we have dozens of these tanks, it seems prudent to build light strips that cover multiple tanks. I've plowed through many vendor sites and get more lost as I go! Much of the information I'm finding for planted tanks involves light penetrating to the bottom of the water column. Since I'm working with floating plants on the surface, I'm guessing I can go with lower power LEDs (or dim them?). Having too much power, in this case, is a negative since it will add to the heat load of the room.

I currently have a Beamsworks 36" unit (6500K) on another tank that seems to work great with the Salvinia. It's 6" above the water and gives me a PAR reading of 33. If I could get something similar in a coil so we could build our own strips, that would be great. To me, this is very similar to an algal turf scrubber in principle.

Any advice would be wonderful! :biggrin:


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## Michael (Jul 20, 2010)

Welcome to APC--you have an interesting project!

I assume that you need to support rapid photosynthesis so so that nutrient uptake will also be fast. So even though you don't need to penetrate to the substrate, you still need really high PAR. And you don't need the light to look pretty, either the fixture or the spectral output. The most efficient output for photosynthesis is usually high in red and blue light, which gives a weird purple color that we don't like on an aquarium.

My suggestion is to forget aquarium lighting, and look at fixtures made for indoor plant production and/or hydroponics. These products are all about getting the highest PAR at the lowest cost.


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## gatorgrabber (Dec 30, 2016)

Thanks for the response! A big part of what we're trying to sort out is how much power (via light) plants require to do a certain amount of work. Because of this, it'll be interesting to have LEDs that can be brightened/dimmed to see what effect it has on the work the plants are doing. In other words, what's the most efficient combo of light/power for doing XX amount of work (nutrient removal from water). It promises to be fun!

Any suggestions for LED suppliers that have quality lights and controllers?


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## s2man (Nov 8, 2016)

hey there, gatorgrabber. I was just talking to my cousin in Fla. yesterday about grabbin' gators 

You could check the DIY forum for some idea:
http://www.aquaticplantcentral.com/forumapc/diy-aquarium-projects/


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## gatorgrabber (Dec 30, 2016)

Well, this is a great place to grab gators!  I'm a wildlife biologist who specializes in crocs, so the user name was a natural!

I've been going over the various threads, learning quite a bit. Most people, though, aren't really interested in floating plants since they block out everything else in the tank. Most of those who do work with them do so outside. I'll keep digging!


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## s2man (Nov 8, 2016)

True on the floating plants, since they block the light for the rooted plants. They sure do suck up the nutrients though, since they have the emerged advantage of atmospheric CO2. 

Are you doing any experiments with algae? Algae can be made into animal feed; Is there a market for the excess floating plants, other than composting?


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## gatorgrabber (Dec 30, 2016)

There's definitely a potential market for aquatic plants as a food source for livestock. I'm prone to reminding those I work with that energy is neither created nor destroyed, but converted into another form. This is what makes aquatic plants so interesting! The reason for choosing floating plants (or emergents) for wastewater work is that they're not shaded by cloudy water with high solids.

My current issue is finding an LED strip that gives me just enough power to get a certain amount of work done, all the while not wasting power that can't be utilized.


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## flchamp89 (Aug 31, 2016)

S.minima doesn't need a ton of light. Like any plant it appreciates macro and micros. I started with a small handful of collected plants and 5.5 months later I pitch handfuls every week. 

I like Michael answer but I see you want led. Couldnt you do what he mentioned with custom ramp timer. 

Sent from my SAMSUNG-SM-G890A using Tapatalk


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## gatorgrabber (Dec 30, 2016)

I'd like to try different temperature ranges (and combos) and see where it takes us. I'm not looking at aquariums, per se, as the answer but more as a resource for info since you folks really embrace what you're doing. So will the plants adapt to various nutrient loads better/worse while under a certain light spectrum, duration and intensity? We hope to find out.

I'm still curious just how far an algal turf scrubber can be pushed for a home aquarium, but that'll have to wait for another time!


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## flchamp89 (Aug 31, 2016)

Keep us posted on your findings 

Sent from my SAMSUNG-SM-G890A using Tapatalk


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## s2man (Nov 8, 2016)

flchamp89 said:


> Keep us posted on your findings


Yes, please do so. Light quality/quantity vs. nutrient absobsion is of great interest.

Good luck on finding a low cost LED strip solution.


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## Michael (Jul 20, 2010)

I just remembered! There is an LED company that makes custom fixtures, Build My LED (BML). They got out of the aquarium business to concentrate on hydroponics, but should be able to build fixtures to your specifications.

And please do keep us updated. I've been interested in plant-based bio-treatment of waste water for a long time.


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## gatorgrabber (Dec 30, 2016)

Thanks for the lead! Yes, I'll definitely let you folks know how this progresses. I've been using plant filters in aquaculture for more than 20 yrs and have been impressed with how well they do.


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## s2man (Nov 8, 2016)

It has been bugging me. I knew I had seen someone build LED lighting, but I couldn't remember where. I assumed it was aquaria related. I just remembered it was when I was searching for LED replacements for my T8 lamps! So, I searched for 'flourescent LED conversion' and found the page again.

http://www.instructables.com/id/Fluorescent-to-LED-conversion-under-30/?ALLSTEPS

You will need to make sure your LEDs are dimmable and source the appropriate power supply. But, it looks very simple.


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## gatorgrabber (Dec 30, 2016)

More good info! Just to be clear, I'm focusing on LEDs that are cost effective to operate long-term for a better ROI. One of the biggest costs in aquaculture/bio-remediation is electricity. Little savings can really add up with a large operation!


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## gatorgrabber (Dec 30, 2016)

By chance can anyone suggest a good, middle of the road, PAR meter? I'm looking at the Apogee MQ-210 (200) but don't know if that's extreme overkill for what we're doing.


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## Michael (Jul 20, 2010)

Our local club bought an Apogee 4 or 5 years ago for shared use by members. It was really the only viable meter available at the time, and is still working perfectly. I recommend it. I don't recall the model number, but they probably have new, improved versions now.


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## gatorgrabber (Dec 30, 2016)

Thanks for the info. I'm thinking we will go with the Apogee and worry about other things.


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