Backyard Aquaponics
A place to discuss aquaponics

After reading the human pump thread I have been giving aeration so thought. I have considered making a very large shallow pond for max exposure to air , but that is not practical financialy as the space and money require just can't work even though it will provide the oxygen. There might be an option to build a water wall that provides a large surface area and very thin film of water perhaps with some bumps to splash it about, but that does not seem to exciting to me either. Oxygen concentrators cost about $2,000 USD and is really beyond most BYAP (build you-own Aquaponic system) people. Buying bottles of oxygen is neither sustainable and I just can imagine it being cost effective; input welcome. So what does that leave? Spray bars, large grow beds, greater water fall distance on water return from pumps and grow beds, air pumps and diffusers.

Since bubble size and water circulation from bottom to top of the pond/tank is so important I can not help but think that an electrolyzer might work; it would get the oxygen from the water. If encased or made from a pipe inside a pump its lifts water as well as an air lift pump. Often the bubbles are so fine that they fill the entire container before they combine with other bubbles and raise to the top(the water looks foggy with tiny bubbles many of which will drift downward and dissolve). Just to see what Im talking about, watch this video http://www.youtube.com/watch?v=1kpswB6Ae-o and notice how much gas comes out of the water when the ultrasonic device makes the bubbles collide and form large bubbles. It would even be possible to place a cheap felt "membrane" between the plates to collect the hydrogen separately and vent out of the water.

So, its my theory that:
1) Such a device could provide plenty of pure oxygen for the fish.
2)Breathing hydrogen is not harmful and because of its weight and atom size will rapidly leave the water body as well as the the fish bodies and not dissolve into the water as readily as the oxygen.
3)The bubbles are atom size to start with and therefore will dissolve into the water even better then a U tube oxygenater.
4)Very little power would be required to produce "large" amounts of pure oxygen
5)This can be a very efficient and cost effective way to provide oxygen. No energy is lost in air compression and there is no wasted motion in the pumping process. **

Now, here are some unknowns. IF you have knowledge in this area please chime in!
a) What effect will electrolysis have on Ammonia?
b) What effect will electrolysis have on Nitrite?
c) What effect will electrolysis have on Nitrate?
d) A good water pre-filter will most likely be needed OR frequent plate cleaning


I really need an oxygen test kit to try this out so I have added it to my list of items to purchase (pending bosses approval). I have several orange tilapia, they are neither a good shape or size of fish for eating, so they will be my test subjects. I need to setup a test aquarium of some sort. Im not sure if I should try to directly capture and vent the hydrogen or just let it loose in the water and let it find its own way out.. Also, doing this indoors could be dangerous in large systems if the hydrogen is not vented outside.

NOW, the other alternative science part of this thread:
Magnetic fields in a biosphere tank has proven, at the creation research institute, that fish growth is greatly increased if you double the magnetic field (in reference to the earths field) and that increased atmospheric pressure also had good benefits. Now, I don't want to double the life span of the fish like they have done with fruit flies, but I am very interested in doubling growth rates! So the question is how do I go about adding to the magnetic field around a test aquarium? Do I wrap a large coil around it or would placing small rare earth magnets at each end work? The biosphere test was a large metal tank with a coil wrapped around the outside of the tank, but I'm not going to have a metal tank. I think this must be tried because imagine doubling the grow rate of fish without adding hormones ect! It would awesome to have 800 gram tilapia in 8 months or 400 gram tilapia in 4 months! That would double the productivity of a system and allow me to grow two "crops" of fish per summer! I have got to wonder if they fish would need to eat more...




** side note close fitting solenoids and back emf collection would WAY more than double the efficiency of an air pump!!

when thinking about efficiency, think about the extras you're making. in this case, you have two potential sources of oxygen, one in the air, and one tied to hydrogen in the water. that's a difficult bond to break, much simpler to use the oxygen that's already existing in the atmosphere.

If you're not keen on diffusers, I've had a theory that a well designed spiral pump's main source of inefficiency is increasing dissolved gasses in the air. Since you have a large number of air water interfaces at greatly elevated pressures, you'll push in a bunch of extra air. The trick is to increase the o2 content of the air and decrease the n2 content, or else you're wasting 80% of your diffusion.

Its the fact that the bubbles are microscopic means very little oxygen will be required. 1 liter of gas can be created with very little power. one third of which of which is pure microscopic oxygen. I dont think it will use near as much power as a pump and bubbler to achieve the same or higher level of oxygenation. I will have to get an oxygen test kit to prove or disprove this.

There is a point at which super saturation can occur with very small bubbles DanD....

And very small bubbles can enter the fishes blood stream.... especially nitrogen, (if using normal air, which isn't the case with electrolysis), literally causing a problem similar to "the bends"....

Suggest you research a little to find the parameters...

The other thing to be aware of if electrolising water... is the effect on pH by all those "free" H+ ions....

doesn't electrolysis tend to release other gasses from salts in the water, some toxic i.e. chlorine?

Interesting idea, Dan. I do know that running current through saline water does make some interesting chemical reactions, but not sure just what. Try it with a few goldfish and get back to us, just don't run the goldfish and power in the same barrel or pipe!

I seem to recall a prior few posts on this...here: viewtopic.php?f=8&t=1409&p=139520&hilit=electrolysis#p139520

Maybe one could collect H2 bubbles for other use while allowing the O2 to be swept away in the current for the fish?

I am a bit dubious about electrolysis when you have no control of the electrolytes in the water (as Novaris has said)
how about one of these http://en.wikipedia.org/wiki/Oxygen_concentrator

Thats how salt water pool work I think. A current through the water turning the salt into chlorine. That's why every year you had to add more salt to the water as chlorine can be gassed off. Where a salt water aquarium does not need salt added very often. Unless you are doing water changes.

thanks hydrophilia for posting a link to my posts to the subject I though had disappeared, much appreciated

I have been in direct contact with the man who owns the patent on electronic electrolyzers for livewells on fishing boats:
http://www.o2marine.com/index.php

obviously the man is an expert at marketing as you can see from the many links on his website

after a few promising exchanges, all went dead at the end of august, presumably on the pretext that trade fairs were keeping him busy

but I think the real reason lays elsewhere: I reacted negatively to his suggestion to invest some money into his company as long as I had no data to confirm the efficiency of his system

I consider the electrolyser idea as a dead end.

But please continue investigating it

Frank
PS for all I know and have read, the system produces very toxic by-products if used in salt water, not in sweet water