Backyard Aquaponics
A place to discuss aquaponics

Have seen these before on landline. Some dude was generating his own power from a sml plastic lined dam.
A good byproduct he had going was brine shrimp that he introduced and now they are an ongoing harvest for him to sell as fish food.

Steve, isn't salty water heavier than fresh( can't remember ) I would think that more salt = heavy density thus saltier water to bottom?????????????

http://www.solarponds.com/

ok, so what makes it heat up so much?

Normally, convection will cause heated water to rise and circulate, distributing any heat gains. Because the salty water is denser and sinks, the heat is trapped at the bottom of the pool. It's not so much that it heats up more, it's that it traps the heat it gets better. The pool must be still so that the layer of salty water can settle and form.

Not being picky Janet...

Common misconception like "hot air rises"... no colder, denser air displaces the hotter less dense air upward.

So yes ...



The salt water traps the heat better and being denser sinks.... only good as you say in still conditions

Hi,

This site provides a simple explanation of how solar ponds work.... http://edugreen.teri.res.in/explore/renew/pond.htm



The bit about "several metres deep" is the awkward bit, but then we're not trying to generate steam....or to desalinate water.......so we don't need such high temperatures. What we'd have to determine is whether a shallower pond would provide the temperature we need.

Covering the pond (large tub) with a sheet of glass (or similar) may also assist.

This link shows a science class experiment which demonstrates the zone effect of solar ponds. See.... http://matse1.mse.uiuc.edu/energy/b.html

Gary

This is where I got some of the info from: Shallow Solar Pond

The art is getting the 3 separate layers and to keep them separate;
fresh water, gradient and salt solution

Thanks for all the info and links all.

Dissappointing morning this morning with 2 dead fish. One each in the vat and the poly tank. Unexplained, perfectly healthy looking fish (to me) apart from being 99% dead and upside down on the bottom when I found them. Does anyone know what that means, if anything? I tride to "swim" the first one around for ten minutes LOL (fealt like Dr Harry, come on mate, you can do it little fishy) to no avail, every time I let go, upside down it went. Fish number one weighed 95 grams and was 185mm. Fish 2 was 105 grams, 200mm.

They do look perfectly healthy and beautiful. Not a mark on them. No ideas off-hand, but observe the still-living ones carefully for any signs of stress. The other thought is that they actually are big enough for autopsies. I've never done an autopsy myself--I usually have had obvious indicators of what I did to kill the fish.

I have kept the biggest one. The smaller one went to the chooks. I will autopsy it if someone can give me something to look for. I have no problem with doing it, just no point if I don't know what I'm looking at.

AA said once to look at the liver (worked with snakes in the outback) - "if it's got a good liver it was a good live-r"

Too many bourbon and cokes for those fishies eh?

My cousin summed it up me thinks. Fish die. Thats a fact. If any more die, I will start to worry.

Eat him.

what? the cousin?

I was going to suggest the same! bit of chilli? Should be fine!