Backyard Aquaponics
A place to discuss aquaponics

tamo42 if you look at the sketch the water coming in has a one way valve so when the pressure builds up the water would try to reverse causing the valve to shut and the water to look Else where to get out

Steve do you think that the can would survive this?

but then how do the fish stunners work? The ones that uni's etc use to capture fish.

never even heard of them

here

this is the first reference I came across

Hi,

I've your tank is live, your fish are dead.....period!

If I walked into my shed and found all of my fish dead, switching off the power would be my first reaction. (Actually, it would be my second reaction - my first would be to say a whole heap of filthy stuff).

The idea of using compressed air to move liquids is very common (assuming that the vessel is up to the pressure) in places where liquids have to be transferred.

It's a good system where the tank contains solids and it would work (for example) if moving buffered clean water from a closed top up tank to the fish tank.

Virtually every tank on a submarine is emptied by compressed air......from the sullage and sewage tanks to the ballast tanks. I was going to use the word 'modern' when I referred to submarines but then I remembered that it's 34 years since I last put to sea on a boat.

With all of that, it would be more efficient to use a small electric pump.

Gary

the best stunner i know is still a stick of gelly

You'll notice that the fish stunner has TWO LEADS and the stun radius is BETWEEN them which is the current flow path.

if you put an extension cord into the water then maybe you fish would die, depending on how close to the cord they got. The current flow would be greatest between the two pin outlets and then would greatly reduce exponentially from that point onwards.

I'd bet a large sum that if you put only the active lead (simulating a break in the insulation of the pump) into an aquarium you'd get nothing.

An outdoor IBC is probably a different story as there may be a fair capacative coupling to ground via the large PE/water interface.

An RCD (GFI for our american friends) will save your life, doen't mean you won't know about it I dropped a powered up 150MH light fitting into a marine tank i had. The RCD tripped, i reefed it out and flicked the lights on........Fish seems like nothing had happened, and more to the point the fully extended elegance coral hadn't retracted.

I'd be quite happy to test these for the team, but i may be accused of animal cruelty if i am wrong

RE: will the blue barrel survive? I have no idea!

on the hydrostatic testing yes, would get more pressure via your piston method, but i figure that doing it the way i suggested is easier becasue you don't have to find a piston and sequentially add weights to burst point, all you need is the barrel and a compressor........then you can wind the pressure reg out slowly increasing the pressure and can keep it there.

You only need it to hold your to your working pressure, so figure out what you would need for that ie (time to empty, flood beds) and then test it? If I had a compressor id give it a shot.
On GFI's, I was witness to a test placing a GFI protected running hair dryer (I think it was) in a bucket of water, the GFI did not trip, and the item kept running. The water in the bucket was measured to ground and it had full voltage. Has to do with how GFI's operate, measuring the voltage or amp difference. ....Scratches his head...

measures the current supply into active and current return through neutral.

Normal they should equal, if there is more through active than returns through neutral the the difference is going to ground, hence a ground fault, over here the standard issue ones are set to 30mA though you can get 15mA ones.

Most hair dryers are double insulated with no earth pin, couple that with drains being run in PVC now and it is not surprising that the GFI did not trip.

Having said that a person sitting in the bath may have been fine, had they stood up and placed one foot onto the bathroom floor then the GFI would have tripped instantly.

GFI will do nothing to stop a death (a nasty BBQ one) if someone was fool enough to stick fingers into BOTH active and neutral (assuming that there was less than 30mA also flowing to ground). As far as the GFI is concerned some one just switched on a toaster

I'm getting serious dejavue have we had this GFI discussion before?

not here, but i've had it beofre with other people............. its almost a good a fight starter as politics and religion LOL

i once offered myself as the test subject to settle the argument........the other blokes wouldn't do it to me!

LOL, Had a few in ya when you made that wager?

nope which is even scarier!

Pretty much all living tissue is worse off after electrocution .

Electrode on head, electrode on tail, apply voltage = crispy fried fish.

The reason lightning striking the ocean doesn't kill (lots of) fish is because non-deionized water is an excellent, fairly uniform conductor. So in the ocean a lightning bolt striking the surface is a huge amount of electricity, but it disperses fair and wide so the effects even just a little ways away are negligible.

In a small tank scenario, this spreading needs to be coupled with the path to ground. What that might be depends on your system. I have a big plastic tub which is fairly well insulated. It would take a very high voltage to create a voltage drop across the body of water (or a high frequency to null out the capacitance value of the plastic). Neither of these is terribly likely, so my future fish will be safe from electrocution (probably!)

spot on