Backyard Aquaponics
A place to discuss aquaponics

Has anyone us tried implementing a modified Dissolved oxygen reactor in their system. I stumbled across it on YouTube. I was curious if modifying the design to use compressed filtered air would increase the DO in the water in a system. IF your curious as to what it is go to www.eco2tech.com I think it may be a good Idea but I will have to try it.

I'm really curious about what this may do in a Aquaponics system

Using atmospheric air in a pressurized reactor can lead to gas bubble disease.

Little bit expensive to buy bottled oxygen just to pump it into your fish tank. Are you planning on raising the stock density to a level where the fish is just covered in water?

As smathew said REALLY BAD IDEA.

Downflow contactors are great if you are adding pure oxygen because you can get them to absorb over 90% of the oxygen you are injecting and if they are tuned correctly you can get them to absorb all the oxygen you put in them (albeit at reduced capacity).

If you are using atmospheric oxygen or air then you are adding lots of extra oxygen but you are also adding massive amounts of N2 which basically causes your fish to get the bends or gas bubble disease as mentioned by smathew.

Just like swirl fitlers, biofilters, screen filters, uv-lamps and other components developed for commercial RAS you can use pure O2 and a oxygen cone if you want but its a lot of money for a hobby. Mind you some people are quite happy to poor money into a yacht.

I see, that makes a good amount of sense.

The best/most efficient option I have seen for aeration if people are worried about their O2 levels is the Low Head Oxygenator (LHO) developed at Cornell University. All the information you need on how to design and operate one is one their website.

Getting an air pump and throwing some air stones in the tank is the simplest option but the LHO is a more elegant efficient option.

Here's one of those calculators that seems so hard to find...

http://bee.cornell.edu/cals/bee/outreac ... wnload.cfm

The Cornell site is full of gems for those that might want to take more of a proven aquaculture direction in terms of RAS...

I received an email from the company that markets this. They have heard of it used in small scale aquaculture but not Aquaponics here is the email they sent me.

Terry,



We occasionally have people express an interest for aquaculture and aquarium applications, but you’re the first for aquaponics. Yes, air can be used instead of oxygen on a small scale. How much dissolved oxygen do you require for your system, as in you need to keep “x” gallons above 5 mg/L, etc? Is this a hobby type system or something you are going to commercialize?



Regards,



Kevin A. Jacobs, P.E.

Director of Engineering

ECO Oxygen Technologies, LLC

3939 Priority Way South Drive Suite 400

Indianapolis, IN 46240

Mobile: 317.366.8191

Office: 317.706.6487

Fax: 317.816.0940

Email: kjacobs@eco2tech.com

Website: www.eco2tech.com

So what would be a good saturation level for Oxygen per gallon be?

You want to keep the water "saturated" with oxygen. The number of mg of O2 per L that is saturation varies primarily with temperature and pressure. Freshwater at 20c at sealevel will hold about ~9mg/L.

The problem with using an oxygen cone for aeration is that you cant operate it under pressure or you will give your fish the bends. It will cause a significant increase in your total dynamic head which will either increase your electricity usage or decrease your flow or both.

When used without pressure there are NO advantages to an oxygen cone and a bunch of disadvantages. If you want to complicate your system make a LHO. Other wise just have the water jet into the FT from a height equal to what it would do inside the cone and you will get exactly the same effect more efficiently.

If you want to understand what is going on then you need to learn how to calculate gas transfers rates, gas saturation levels and how the DO cones actually work.