Backyard Aquaponics
A place to discuss aquaponics

Hi, I am up in the Dandenongs outside Melbourne. I have recently set up in a new system in a 6 x 3 M greenhouse. We ahve been pumping water for around 4 weeks now.

At the moment I have 2 x 1000 litre IBC's as fish tanks inside the greenhouse as well as 6 ibc grow beds with scoria as the media. I haven't filled 2 of the beds with scoria yet only due to time but they are plumbed in (but isolated), these will be my expansion once the system is up and running. I have around 1600 litres of sump outside the greenhouse which is also covered.

I have added 20 gold fish to the system and they seem pretty happy so far and I am now thinking of adding some edible fish, my first thought is Silver Perch. My big issue I may need to overcome I believe is water temperature. In the winter months the sun drops below the tree line and we have limited thermal energy, in summer we get full sun. The greenhouse is working well and will definitely extend our growing season. We have a few tomatoes planted in dirt and we already have fruit. Normally up our way we woudl be lucky to see fruit in February. The highest temp the water has hit is 22 degrees C so far. So unless we get sustained 30 degree plus weather I can't see the water temp exceeding 32-35 degrees in summer but in winter may be lucky to maintain 10 degrees.

So far the nitrafication cycle hasn't started we have a few plants in and we are seeing growth, following advice on the forum I have added seasol, should I (could I) also add Charlie Carp as an amonia source? We are very lightly planted, at the moment.

Will Silver Perch be my best solution long term? Ultimately I am hoping to grow trout through winter with a population of perch through summer. I believe I will have to stock lightly due to limited plant growth through the cooler months due to the lack of sun. I don't really want to heat water if I can help it.

Thoughts on fish type and stocking levels would be appreciated. Once I have enough posts I will add some pictures.

Is there anyone else in the Dandenongs

Cheers Al

Like me you might have a problem with silver perch through the winter (too cold).

Also like me you might be able to get trout through the summer.

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I'd look at a rocket mass heater for the GH. Tiny amounts of wood generate almost no smoke and heat for hours. You could even have the rocket part outside the GH and the mass part inside.

I kept my SP's feeding over winter by using timers to turn my pump off overnight (at 5:30PM) and a small 300W heater on, then vice versa at 8:30AM. My air pumps ran the whole time and I saw zero effects in water quality.

It doesn't take much to keep things warm enough for them, particularly if you insulate the FT/ST and stop pumping warm water into a radiator that a GB is when it is coldest.

Also look into passive water heating (black tube in glass faced box) and trombe walls for alternatives to electrical heating. Anything behind glass only needs light to work, not heat, so if it is daylight you are getting at least some effect.

Thanks. Any idea were I may find a rocket heater?

Look on youtube, they are very easy to build.

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JRL91RS

By the way, I am no expert, but I know what has worked for me.

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I have recently added 30 Silver Perch as I noted temps around 26 degrees during that burst of hot weather a few weeks back here in Melbourne. I have since added some shade cloth which is definitely helping to keep the direct heat off the scoria. Fish seem happy and I have added salt tonight using the advice from the forum, added 2 kgs tonight and will check the levels before adding anymore. The fish seem happy and the plants are showing some good growth. The only slight problem seems to be getting the plants to pollinate, any ideas how I can encourage bees into the greenhouse would be appreciated. For example our Zucchini flowers are just dropping off without setting fruit.

The ph is sitting at around 7.4 and there appears to be only trace levels of ammonia with zero nitrate and nitrite, should I be concerned about the low nutrient levels?

Next stage is to complete my "alternate power" setup by adding 500W's of solar panels and an inverter to run the main pump. Will also have a mains fail setup and a DC pump for aeration should the power go out. Luckily I have been able to scrounge up some batteries.

Any advice on attracting the bees would be appreciated? We leave the doors open during the day and the are automatically opening vents as well.

Not sure how to get the bees in there however maybe just self pollinate them for now if you want some to form. Zucc's just grab the male flower and remove petals then wipe over inside on female flower leaving pollen behind.

If you aren't set on varieties then look for Parthenocarpic vegetable seeds for crops that you have problems with. Parthenocarpic vegetables don't need to be pollinated. Here's an example - http://www.johnnyseeds.com/p-8311-partenon-f1-og.aspx

Here is a website with an explanation and some varieties that are Parthenocarpic at the end.

http://counties.cce.cornell.edu/westchester/Homeowner%20Newsletter%20Links/PARTHENOCARPY.html

Thanks for the advice, will try self polination method and also try to track down the Parthenocarpic type seeds locally for next time. I checked on line and found a YouTube clip. Not sure if its possible but all the flowers seem to be male. Anyway the good news is that after work tonight I found a bee drinking from one of my grow beds. Hopefully he wasn't the Lone Ranger.