Backyard Aquaponics
A place to discuss aquaponics

I've had my system for nearly 18 months now and I still cant decide what's the best sort of fish to have. The climate in Adelaide has hot summers and cold winters. I've got a panel from a solar hot water system at home and in other threads you've given me heaps of good ideas about using it to make either a water heater (to make my silver perch and catfish more comfortable during winter) or as a water cooler (to stop my trout dying during summer). Now its time to decide and I again ask for your help.

There's pros and cons for both sides:

Use the panel as a heater
Pros:
* the sun is free
* I'd prefer to eat fish like SP, catfish
* could maybe even do barra
* can extend the growing season out for pretty much the whole year instead of just 5 months
* I'm guessing the plants would grow better if the water is warm?

Cons
* it would be more expensive to set up (buying pumps, hardware, etc) and running cost
* most of the warm water fish have to be imported from interstate
* best price (including freight) is around $1 a fish for a fingerling around 30-40mm but you must buy at least 100
* SP and catfish will probably take 2+years to grow out
* in my system you dont often see these fish, even at meal time, they prefer to stay on the bottom

Use the panel as a cooler
Pros
* cheeper to set up (no pump required, can thermo-syphon the water)
* can buy trout fingerlings locally, dont have to pay freight (approx $10 petrol money)
* cost around $1.20 for a fish around 150-180mm, minimum purchase 50
* grow to eating size in 6 months
* a great spectacle at feeding time!
* smoked trout

Cons
* the technology is so far unproven, but some of you experts think it would work
* if the technology doesn't work the fish will die
* will need a much bigger air pump
* can only run one species (trout), no point mixing it with anything else if I'm cooling the water
* will have to think of some different ways to cook them for a bit of variety
* might need to build a smoke box (see pros)

Im for the pool option .

my mother , who is usually sceptical of my schemes , hasnt SEEN my system , but dad saw it ( and the trout , unfortunately he's got a fishing rod handy and its near a fence ) and went home and told mum , she insantly decided that fish would definitely grow in their pool , and came and asked me how many they'd fit

chalk up another convert

+1 for trout all year round

Run 2 systems, one for barra/SP

+1 for trout with the panel.

and Yes, they are awesome to feed

Why not run 2 systems, switching the panel from cooling in summer *(when the trout need cooling) and heating in winter (to help the SP along) With a few ball valves you could arrange the panel to provide the best of both worlds.

sorry, no option for this, so no vote from me.

Tony

I like the two species option. Seems to work for Faye alright, and it may be worthwhile to get experience with multiple types of fish too.

I was leaning to the cool option on the grounds of simplicity of operation, there are a few drawbacks I could see in the system however. The FT is relatively small and the GBs are NFT. I would be concerned about the possible temp swings in summer (day/night) and the chances of multiple cloudy nights reducing the effectiveness of the cooling effect.
The solar panel would need the glass removing (and painting flat white , controversial) and preferably pointed to the south sky. I would be very dubious about it working efficiently for cooling in its current state. Vege's and bacteria would grow slower in cool mode.

Heating is complex to control operation, also the drawbacks with piping to the solar panel. See also the caveat on day/night temp swings.
Am still of the opinion that the solar panel should be connected to a storage heater (eg rheem) and the heat or cool bled from that. Sounds more complex but in effect simplifies the controls etc.

KE Have you got any data on temps ie summer day/night and winter day/night to give us an idea of how much water temp has to be moved? An if someone says its in a thread

If you have a swimming pool and 'her indoors' is wavering, that would get my vote

I like trout as much as the next guy, but my concern is plant grow-outs being slow/stunted from the cool water.

So +1 to warm, and +1 to experiment with small cold system

The fishtank is 1500 litres and well shaded.
There is about 800 litres of gravel growbed plus 10m NFT
Water temp got up to 25C during our recent heatwave. In winter it gets down to 11-12C

The only problem running with 2 species is that the SP will only have about 5 months where it is warm enough to eat/grow and the rest of the time fairly dormant. That means it would take at least 3 years to grow to eating size.

tamo, plant cool weather plants!

Will the cool weather plants grow enough, and feed enough?

yep

http://www.humeseeds.com/falwint.htm

I think you should heat the system you have for the silvers, and raise the trout in the pool during winter. (how much do you use the pool in winter?)
H.

Cool, I'll be prepared for winter this year!

I'd go for the fish you prefer to eat

I kinda second the idea of going for what you want to eat most! If that means the silvers and catfish, then setting up the system for some heating with the solar water heater, then that would be the way to go. I doubt it would need an extreme amount of extra controls. You just need a small pump and perhaps an insulated vessel to store the hot water until night time when you would then need to open up the heat exchanger to the system.