Backyard Aquaponics
A place to discuss aquaponics

Thanks GM, yes I've also used electrolysis to produce more than a little H2 + O2 in my time, and been in trouble for exploding it in a large plastic bag my bedroom as a 16yo
The problem with Carbon rods is that they gradually fall apart, and have nowhere near enough surface area for the power I want to use, except in large numbers, which is not practical. Thin sheets of Platinum would be best, but it doesn't seem to be available. One place that supposedly sells it didn't bother to reply to my email (a surprisingly common feature of many businesses, so clearly they don't need my business!) Copper and Zinc are out, and I'm a little concerned about stainless steel, which apparently slowly corrodes away, and it contains Nickel and Chromium, which would not be good for the fish.

I suspect I'll end up using Copper or SS, but in a separate sealed container to supply low pressure O2 to an airstone in the FT, and vent off the H2 somehow.

Guna,
i posted this in battery backup thread.
could you please have a quick look at this and see if this would even work?

im thinking of going to one of his workshops early next year in the hopes that it is good, but would like to hear what someone who knows a lot more about solar and batteries than i do has to say.

i kind of think, why wouldnt it work, but then i think if its so easy why hasnt it been done / why arent batteries simply made with better electrolyte in the first place?

http://www.rainingspiritdojo.com.au/dow ... s-v1.2.pdf


Edit:

@your post above: Dont forget you need an electrolyte to make the seperation of H and O work well for your power usage, and if you use salt, then you wil have sodium off one and chlorine off the other, which off which i forget.

It was a case of TL:DR all of it, but whilst it may work for a while, I don't imagine it really lasts as long as using the original H2SO4 electrolyte. People have been experimenting with all sorts of different chemicals for batteries for a very long time, so I think if it really was viable, it would already be in widespread use.

Yes, well aware of not being able to use NaCl, but have done the experiment before (about 40 years ago!), just to see the nice red colour of Chlorine burning I have plenty of NaOH and KOH on hand to use. Bubbles of H2 from negative, O2 or Cl from positive electrode.

thanks guna.
I really am hoping it works, ill rescue hundreds of batteries for my solar setup, but i would hate for one to die after a year and have to find the dead one.... or to replace the electrolyte every year. :rolleyes:

i think ill still try his workshop, although i think it costs a little money, he does the converts for people with large battery arrays for their houses, for free i think, so atleast he isnt simply a scammer.

What sort of pressures did you achieve with your experiments 40 years ago? (lol dont worry im not expecting you to remember).

when i did the same 10 years or so ago, i tried to use a balloon instead of a shopping bag, even well stretched out, i couldnt get enough pressure buildup to blow the balloon up.

So basically i hope you have your outlet tube next to the inlet of an air pump.

or better yet, if you are injecting pure O2, make yourself a downflow bubble contactor (or the hundred other names it goes by) instead of injecting straight into the tank, seems a waste if the bubbles make it to the surface.

In a lot of old batteries the plates have virtually disintegrated, it wont matter what you put in them, they'll still be as dead as the pile of Lead-rich sludge sitting in the bottom of the cells.

Just saw your new post- bugger all pressure- the explosion came when the gases ignited thanks to the wires inside the bag, which were connected to my dual car ignition coil with buzzer giant spark machine

The pressure will come from the head of water, ie, the depth of the airstone in the FT and being in a sealed container. If I make the reservoir large enough, it wont need topping up too often- need to do some calculations on required size. I'll need to make sure there is more pressure (head of water) with a brass tap at the top to vent the H2 at twice the rate of O2 production, so the O2 doesn't all leak out there.
Yes, I'd prefer minimal bubbles making it to the surface, so they'll need to be very fine and dispersed. Maybe I'll deliver the O2 to the inlet of the circulation pump, which will give the gas more time to dissolve as it is pumped around through the UV sterilser and chiller- I'll need to experiment to find the best way to do it. The idea is to have it producing Oxygen whenever the sun is on the panels with the only intervention required being water top ups.

I wouldn't run pure O2 through any sort of FT air compressor with rubber parts, as the hot rubber would oxidise and deteriorate very quickly.

oh didnt know that about rubber.

it sounds very much like you have things in order lol.
i didnt just remember however that there was a horrid buildup of black shit when i did the experiment, maybe it was because we used salt :shrug:, but if not then you will need to make provisions for cleaning too.

You have to be very careful with running pure O2 through compressors not designed for it, especially ones that have oil and get hot.

If you used Carbon rods for electrodes, the black stuff was probably them falling apart.

Electroplating coins in a solution of Copper sulphate is fun too- I've got a 50c coin floating aorund somewhere that is covered in lots of copper crystals, which looks pretty cool.

yea we tried metal probes first, but obviously they eroded pretty fast, we then moved to the carbon rods from 6v batteries.

it isn't just rubber that will oxidize quickly in presence of pure O2. Look for air stones and tubing appropriate for use with O2 since regular air stones with poly barbs don't last long for O2 use.

Temperature plot for 22/10 to 1/11, when it was a bit cooler than early in the month. Water in yellow, air in red.

Yellow plot of water temp for November to this afternoon
24kg of ice added on the 20th and 14kg on the 21st to keep the temp rise down a little bit, but the next 2 days may be more of a test. I'm turning the water to the outside GB off during the daytime, and spraying water mist around inside the GH a few times per day to cool things down.

Today's 37C with crazy winds was rather unpleasant, but the fish are ok for now. The water is on 22.9C ATM, I've dropped in 15kg of ice to keep it a few tenths of a degree lower today. I've had a bit of demand for the trout and not many are left in the freezer, so we harvested 9 today, 3 for lunch, 5 for the freezer and one to a mate for giving us a hand today. Weights ranged from 400 to just under 700g.

Lunch:

With some ice additions on hot days I've managed to keep the water temp max under 24C, and the fish appear to be behaving normally, with no deaths recently. I'm not feeding them much lately, as they will all have to come out soon. We netted out 11 more this evening, weights ranged from 370g to 650g, with 5 others in the mid to high 500s range.



I did catch the lone Murray Cod a few days ago whan catching trout for lunch, it is still quite small, rather disappointing for a 2yo fish. It went back in, and at this rate I'm expecting it to be plate size in about 5 more years.

Yellow plot for the AP water in this system up until yesterday, not doing too badly in the hot weather, with the addition of some ice on the hottest days. Over 35C today and forecast to be hotter tomorrow, and remaining in the 30s for the next week, so I don't think I can keep them too much longer. I've stopped making ice, with heaps now in the freezers.

I've barely fed them for the past week or more, and if my wife gets home early enough this evening, we'll take at least half the remaining trout out, and probably all of them within a few days. I'll just take some of the poo from the big system filter and add it to the ST over summer, until the water becomes cool enough to reintroduce trout in autumn. I'll cut overnight water pumping times back and reduce air to intermittent, as the lone Murray Cod will be fine, and I'll use any leftover energy to keep the big system water cooler.

Right now, it is time to finish picking the last of this year's cherries