Backyard Aquaponics
A place to discuss aquaponics

On this cold winter day with a foot of snow, I've decided to start seriously thinking about aquaponics. Although I have experience with aquariums and gardening, I'm very new to AP. I've got the general idea by reading so many of your great posts here, but have a lot of gaps to fill in.

Here is the system I'm contemplating (see pictures below):

Indoor/outdoor system. In summer, it will be an indoor tank with Tilapia and outdoor grow beds. In winter, the growing beds will be moved inside by east-facing windows and LED grow lights. In winter the fish stock would be reduced to compensate for fewer/ slower growing plants.

Tank: 270 gallon
Pump for circulation with tubing wrapped around the furnace exhaust to help warm up tank.
Two Heaters
External Pump to suck water out of Fish Tank up to Growing Beds
Indoor Grow Beds with simple autosyphons
Outdoor Grow Beds with simple autosyphons

Be glad for help in filling in the gaps....

One of the questions that I have is whether wrapping tubing around the Furnace Exhaust is a good or bad idea. It looks like it should work. Should I be concerned if it would melt the plastic?

was looking at your indoor setup... I didnt see any sump tank... will there be enough water in the fish tank to completly fill the grow beds?

dont want the fish flopping around without any water...

jT

JT,
I'll probably need to add a sump. I was thinking I wouldn't need to, but now it has suddenly occurred to me why everyone has one... the volume of water in the grow beds! Duh.

My first part of my system that I've bought is a large aquarium that I am in the process of getting on Craig's List. The person I'm getting it from misjudged the size. It is actually only a 150 gallon and not 270. It will still be a really good price but just not the super dooper deal I was first imagining.
The 150 gallon might be a better for my maiden voyage in AP land, anyway.

Thing with this kind of setup is, without a lot of research, we have NFI how much pipe to wrap.
So we over-engineer, and wrap lots
This means that if you run a continuous pump, on a day you don't use the furnace much, it will still be warm enough.
HOWEVER!! On the day that your mother is visiting, and the furnace runs 110% day in day out, the water will get much hotter.

Simple fix. Add a temperature switch to the pump power, so it only turns on when the tank is cool.
HOWEVER!! (again) this means that your pipe could be empty for extended periods of time, and this will pretty much only happen when the furnace is too hot
So plastic pipes, even full of water will (eventually) reach boiling temperature.

PVC should be ok at boiling, it will get soft, but only a little soft, SO LONG AS THERE IS WATER. you will need to install a check valve to ensure there is water in the pipe at all times.

Check out what nasty chemicals PVC will release at 120 degrees C (hotter than 100 C boiling point as a Safety Factor)
Also do a test with prolonged exposure to boiling water, with a weight on the pipe (pipe full of water will be heavy and will apply a force between exhaust and pipe).

Best suggestion would be to use metal, so we think copper - This is very BAD FOR FISH, do not use copper.
Perhaps you could get a large piece of steel pipe, or a trough or bucket, and run the exhaust through the fish water.
This will provide a MUCH better surface area for heat transfer, and be a fair bit simpler to build.

How big's the furnace exhaust? how big a pipe from the FT would you want to run?

Simplest solution IMHO would be to lag the pipes to a degree that they only bleed a small amount of temp, then lag over the poly. Make the furnace more efficient too, better air pull

Cool. I have NFI what you just said.
What do you mean by lag?

Means put insulation round.

Ahh... I guesse it might be, but had never heard of such before...

So insulate the exhaust... ok that makes sense.
Insulate the poly pipe... ok... but how do we get good transfer b/w the pipe and exhaust?

If you insulate the poly, it wont transfer any heat...

Sorry KP I get a bit sloppy
What I meant was put some insulation round the furnace exhaust pipe to a point where it will not damage the poly. Wind the poly round then put some insulation over the top of that.

ahhh I see... you are therefore limiting the heat that can transfer into the pipe... this means that heat is being wasted, in order to keep the pipe cool.
Simple, but inefficient

Simple and cheap I would have put it, but yes

Hi Elginite:

Re - your question on my old 2007 thread, yes I did change it to be an indoor/outdoor system much like your design. This info is in my 2008 thread:

viewtopic.php?p=97841#p97841

The fish were in the basement with their own gravel beds for biofiltration, using a continuous pump and four loop siphons. Fish water was exchanged with the outside plant side, which had its own sump and pump on a timer. I put together a pipe-in-pipe counterflow heat exchanger to try to not lose all the heat from the fish water when exchanging water with the plant side. The plants grew very well and I would recommend this kind of setup if the fish can't handle the outside temps.

I am going to start a 2009 thread sometime soon hopefully. This year I want to get a few trout for the Winter/Spring seasons, so I'm not fighting the temps. I still have about a dozen little tilapia that I may put outside in mid-June when it is safe for them.

When growing the plants indoors I was using a 400 watt MH grow light from eBay. There wasn't enough room for large plants in the basement system, and I don't think it was worth the electrical and bulb cost. I ran the tilapia indoors without any plants at all for about 9 months so rather than fight to grow plants in the dark I'd prefer the indoor/outdoor style of system for sure. Or maybe rather than trying to grow "real" plants it could be acceptable to grow just lettuce or other small plants, maybe duckweed, under fluorescents.

I got the light from this outfit, it was the 400 watt MH that includes MH and sodium bulbs:
http://members.ebay.com/ws/eBayISAPI.dl ... =htgsupply

HTH!