Backyard Aquaponics
A place to discuss aquaponics

Knew I'd seen something like this before...
http://www.motherearthnews.com/multimed ... 5988&seq=1
Click around the article.
Someone with a bit more gumption than I might make a simple concentrator attached to this device, making better use of expensive s/s or Al.

There was a company called "SunTrac" that used that technology as a solar hot water system, think one of the big companies bought them out and shelved the design coz it was too good and taking sales from them

Had one, lasted 15 years, but eventually couldn't get spares for it

Ellkay,
What wore out in it? seals?

Ok , Not sure where to put this but my initial searches about copper pipe show there is basically ZERO risk.
Anyway , stainless is better and safer if you can get it at the right price.

Chappo - you seem to have a problem using your eyes reading and listening to much more experienced fish keepers than you!!!

http://www.chilternkoi.baxx.net/Copper%20and%20koi.htm

In case you cant read still :

"Other species of "native" fishes; trout, sunfishes, catfish are even more sensitive, dying near concentrations near 0.10 ppm."

Copper is bad to fish!!



AND : http://www.google.com/search?q=copper+toxicity+to+fish&rls=com.microsoft:*:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA

I have not found a site yet that says using copper in a fish water LOOP is ok. Note 'Loop'. As rupe has already told you, as ph goes down, copper dissolves and kills the fish.

Much lower conductivity is the problem with stainless. All the same, Les and I bought some Tubing last year, with the view of making heating systems for our tanks. I was going to use mine as described below. I got 24 metres, just haven't got around to doing anything with it as yet. I will hopefully get it done by winter 2009

1. Pool solar collector (you know, the rubber strips) on shed roof (already sourced this for nicks, but has a bit of damage that needs fixing).

2. A closed loop with water running through collector from/back into a largish container located in the shed (maybe an IBC, but not sure what sort of temps they can handle??).

3a. Run water that is already being pumped from sump to the fish tank through the stainless tubing which will be located in the IBC. This will act as a collector; or
3b. Run water from the fish tank through the collector (the one in the IBC that is) using a seperate pump. The advantage of this over 3a. is that I could attach a couple of thermostats so the pump only operates between the low and high optimum temps for the fish I'm growing. With 3a. i'd have to work out through experimentation the maxium heat to bring the IBC water up to during the day to ensure that the fish tank could not overheat at night (probably unlikely anyway??).

Anyway - I should run a little experiment this winter to see how much heat I can put into a water source through the day and how efficient it is to then exchange this by using some stainless tube.

One challenge with all this will be making sure that it is not false ecomomy, using as much power in extra pumping as what it would cost to put some heat directly into the tank. With the use of the collector on the roof, I'm not sure whether I would have to run the pump all the time during the day, or whether I'd just have it going periodically to exchange water over from the pipes, which had been sitting there heating in the sun. This would require a valve to stop backflow of course.

Other question is why I wouldn't just run the system without the IBC - the the stainless steel pipe sitting in the fish tank (or better still the sump - where it wouldn't get in way of the fish) and having the water flow through this after leaving the roof. The main reason I was thinking of using the other method was to build up some heat during the day which would then be put into the tank at night when it is needed most and also act as a heat sink (it would be located in the same bay of the shed as my fish tanks, and I hope to close off and insulate this bay).

Thoughts?

VB - according to this:

http://www.briskheat.com/products/tote-wrap-around-heater.aspx

At least 91 deg c - might be just enough

VB,
FWIW, my vote would be for 3b - more control and less temperature difference/loss to worry about.

BTW - how did you come by 24m of tubing? I'm assuming it wasn't new.

Good news re the IBC :-)

Bought the tubing new. Can't remember how much we paid per length (I bought 4, each 6 metres) but was not prohibitive. On of the challenges is the bending, but I'm confident I can do something.

The idea would be to insulate the IBC well (I have heaps of polystyrene sheet that will do well for the purpose). Once it gets to a good temp, I'd not need to pump through the roof heater anymore. With some experimentation, I might be able to work out the most efficient time to do it - ie not do it too early in the morning only to lose the heat from the IBC during the day. The pool collector is reasonably large, do provided I can get most of it working, it should be pretty good at picking up some heat. It was hooked up to a 50k litre pool before - but then it also had a 1/2 or 3/4 HP pump running it (shock). I think a low pressure high head pump woudl do the trick though. May set it up as only a couple of longish runs.

Run it on a timer VB, couple of hours over the middle of the day should heat that IBC up toasty

Will run a trial just using water in a 200 litre blue barrel and maybe one of the lengths of collector. I can then multiply it all out to get a quick estimate. Will of course vary from day to day depending on the sun - but would give me a good idea. Hell - I might be spured into action

don't rush yourself VB

Maybe run a photoelectric sensor, so it only runs when its sunny

Hmmm - don't have one of those (yet ). I do have a switch that turns on when it gets dark though - same sort of thing I guess, just with different parameters . Bought that silly thing on ebay a year or so back. One of my more silly impulse purchases. Thought it might be useful for my AP system in some way. I've changed my mind . But hey - it was a bargain

Hey - just dug it out of the drawer - it is a photoelectric switch. 'HPM Weatherproof Photoelectric Switch PE170/10'. Not much use to detect cloud cover though