Backyard Aquaponics
A place to discuss aquaponics

for what it's worth, when i was a kid i used to work in a hardware store. it was common knowledge that PVC is safe for COLD water supply lines, as well as dwv (drain, waste, and vent). any hot water supply lines are to be run with CPVC.

personally, i worry more about the primer and glue than the pipe itself.

I only use silicon (on the outside) - this way I can pull it all appart to clean/change etc...

Hi All,

I read somewhere that there is some concern with using copper in the systems.
Now I was thinking of using some sort of coil in the fish tank and run hot water through this with a small pump, directly taking the water out of the solar hot water unit on the roof. The obvious choice to pipe this down to the fish tank would be to use copper, and I guess the next obvious thing is to run some sort of copper hot water body througn the fishtank.

If copper is a concern though, I might have to rethink this. How about if I base it on one of Murrays rectangular tanks, and run say a rectangle at low level in the tank, made up from diam 42 or 50mm copper pipe?

To overcome the leaching of copper, would it suffice to paint all the copper that is in the water? That would seal the copper from the water, wouldn't it? And would you get a reasonable amount of warmth to heat up the tank water assuming that the hot water from the roof is some 60 degrees? I was thinking of running the pump say 5 minutes every 20 minutes or so to replace the cooled down water in teh rectangle.

Karel

not sure about the paint thing (would depend on the paint I guess - it would 'break down' faster as heat is applied, thus releasing its own chemicals)
What was seggested was to use stainless steel, but that is a wee bit expensive...
I used polly pipe which was heated by a small compost heap, and that gave some results.

I'd ideally like to do this, but i've found info that even quite low conc. of copper can be detrimental to fish. at the very least you will need to make sure that the PH is always 7.1 or above.

Paint id a good idea, but what paint would you use? if you have found a paint that is suitable for potable water but is not tar / ashpalt based then please post. I'd say that a tar based paint would insulate far too much.

Steve

Forget copper in fish tanks....remember they use copper based paints on the bottom of boats to repel/kill barnicales etc. Stainless is the way to go, but difficult to deal with, bend etc.
There has been a thread on this before, I just can't find it.....perhaps Steve or EB can tell us where that thread was.

This is the thread here Solar Thread.

I still reckon stainless is the go, but will not even put my mind to this further until closer to next winter. Greenhouse first I reckon, along with some passive solar additions.

Here is what the 5 different types of recyclable plastics are (as represented by the number on the bottom of the container.

1 (PET) - like clear and coloured soft drink bottles

2 (HDPE) - like 2L and 3L milk bottles

3 (vinyl) - includes plastic cordial and juice bottles

4 (LDPE) - includes ice cream container lids

5 (PP) - includes ice cream containers and take-away containers

Reason I am interested in this is that some of the storage containers you buy at B or wherever also show these numbers and therefore reveal what they are made from. This could be helpful in deciding whether they are safe to use as recepticals in the aqua system.

Big question is which of these types of plastic are safe for use - all of them?? considerring they are used for food containers as indicated above??

Of course the containers (eg stacking crates) are unlikely to be UV stabilised, so this may be an issue in itself.

Sorry for starting this all over again - but I am really interested in identifying what containers I should feel confident in buying for this type of use (e.g if I want to set up a DWC to supplement my big gravel grow-beds).

nah, no problems with bringing it up again VB!

ok, 2 and 3 are probably the most safe options, 1 probably is as well.

I'd personally stay away from 3 as the plasticiders used in these are dubious.

don't know about 5

The other destinction that needs to be made, LDPE may fine pure, but when recycled in to generic containers there may be all manner of contaminants in there.

This is why you can have HDPE and food grade HDPE the food grade one has been tested and certified to contain no adverse impurities, and is usually made from virgin materials, not recycled ones.

are you serious that 3 is used in juice and cordial bottles?

Great list by the way, i had never bothered to make a list of the numbers........but its VERY useful. thanks

look here for more...Food Grade Plastic Containers For Brining

look here for more[web]http://www.virtualweberbullet.com/plastics.html[/web]

[schild=15 fontcolor=000000 shadowcolor=C0C0C0 shieldshadow=1]hope this works...[/schild]

Very nice AM,

Thats what i was getting at, a PP tab at bunnings is made of the same plastic, but the dyes and or impruties might not meet food grade.

I might bring myself to use a PP storage container from bunnings, clear or white would probably be best. I might have to throw out my black bunning tub that is currently in my system...............soon........

LOL... as will a lot of people .. ::mrgreen:

HOLEY MOLEY! I just remembered that my uncle works at a nut factory (yes i did some work there too) They have red and white food grate tubs that are stackable...........AND what they call palle-cons to store the bulk nuts in. they are 1M high and standard pallet footprint (anyone?) 1500 lt easy.

He owes me more thsn one favour.....................time for a phone call i think

gotta get a few, not just one