Backyard Aquaponics
A place to discuss aquaponics

Hi all,

I've been hovering around this forum for a couple of weeks now & I've just finished reading Joel's book. Now I've got the crazy notion I can build an aquaponics system in my own backyard! Well, actually, I'm sure I'm going to need plenty of advice, but I've managed to convince myself (rightly or wrongly) that I can get started & address problems as they occur.

Anyway, I have a few questions I was hoping you kind people could answer.

1. How much of an issue is it if my GBs (or maybe even fishtank) collect rainwater? Can I just redirect overflow to the garden?

2. How much trouble should I go to, to shade the fishtank? Is an hour of sunlight bad? 2? 3? (I'm in the northern Sydney suburbs, by the way.)

3. Does anyone know where I can get a ~2000-2500L tank in Sydney for a reasonable price? (or a supplier that could make me one?) I'd done lots of Googling with not much success.

4. What water temperature might I expect in my climate? & consequently what fish would be suitable?

5. If I start with 2 GBs (let's say 2x1x.3 for now) & keep the stocking density << maximum - I've read I need to increase the flow rate. That doesn't make sense to me. Could someone please explain it?

Bye for now,

Scott.

Hi Scott,
welcome in from the hover

I'm in a rush so, just one answer for now, some one else will help with the others soon.

1. the amount of rainfall into your growbeds shouldn't be a problem most of the time. Unless you get a HUGE storm that dumps 100mm into your tank Running off the overflow to the garden will be fine, your other plants will lurve it

Welcome Scottie....

Chances are that someone is already in the process of writing a relpy, but here goes.

1. A bit of rain water going into your tank won't hurt. It is only when a significant amount of rain goes in do you start to see the changes in your water chemistry. Your pH will most likely be affected, and possibly your hardness if you have it adjusted. It will severely dilute your nitrate levels, which should take too long to build back up again. Worst case is that the bacteria in your grow beds are knocked by the change in water chemistry and the cycling process may be a bit sluggish.

2. Most aquaculture places keep their fish either inside or under heavy shade. Sun can cause higher stress levels in the fish, will cause the temperature of the water to rise (this may be OK for tropical), the main issue is with algae growth within the tank. Algal blooms love light. The sun you are talking about is OK. However it is best to cover the tanks in some way to limit leaves and debris entering into the water.

3. Not sure on that one... I am sure some local members will help you out.

4. I imagine Sydney climate would be fairly similar to Perth, Warm summers and cool winters. Not too much extremes. Silver perch are a favorite ideal starter fish. They will live happily in fairly cool water ~ 14 degrees and warm water below say ~26 degrees. Trout could be an option in winter if you can keep it very cool below 20 degrees with PLENTY of oxygen. Barramundi/Jade Perch are two popular warm water varieties (26-28 degrees) these would most likely require heating. A little tip for starting off.... Goldfish are hard to kill.

5. With a ~ 2000L fish tank an 2 ~600L GB's I would imagine that you could stock a reasonable amount of fish with out having to go to huge extents. The greater flow rate idea could mean that because the ammonia concentrations are low (low stocking density) then it would take extra passes for the bacteria to convert enough nitrate to feed the plants.

You can't have too much growing media, the bacteria will multiply depending on the ammonia/nitrite levels in the system. However generally speaking having less fish means you can support fewer plants.

Hi all,

Jaymie: I read your thread in the member's section (took me a few nights!) - it was very inspiring!

By my rough calculations, 100mm of rainfall will cause ~1/3rd the volume of the water to be replaced.



Ok. So I assume the pH & hardness of rainwater is different to tank conditions. Is that right?



Oh, ok. That makes sense. For some reason I thought nitrate levels were ~zero at any point in time.



I haven't read much about heating. What equipment do you need? How economical is it to run? (I think I'll walk first, though. )

Scott.

Gday Scottie, ur moniker is my surname minus the ie. Read worms thread, send him a pm and go get 3 bathtubs off him. Cost 15 bucks. Use one as ur fishtank and two as GBs. Call this ur starter system. Won't matter if u fubar and will cost u buggerall to set up.Put an overflow pipe in ur fishtank or a cover over things so ur fish don't get washed away in the event of heavy rain.
AP is simple if you follow very basic principles. As for heating, go to an aquarium shop. Heater for 300lt tank will cost u 35 bucks or so and is perfect size for one bathtub fishtank. Get stuck in mate, its a ball o wax and will change ur life.
Tragic

scotty, i don't worry about rainfall at all, it absolutly bucketed down here yesterday, there was an increse in tank voulme, but not huge, i have a bathtub exposed to the rain and 1/3 of the tank.

can you list the math you used to come to the 1/3 water increase, it seems quite high (but might be right).

Steve

Hi Steve,



Sure. It's just a rough calculation:

Surface area of grow beds is 4 square metres. (2m x 1m x 2GBs)

Surface area of fishtank is 2.54 sqm. (assuming 2000L 1.8m diameter circular tank) A = pi * r^2

So that's 6.54 sqm. With 0.1m of rainfall that's 654 litres - approximately 33% of a 2000L tank.

Maths is fun!

Scott.

hehehehehe, sure its fun, just follow the pages below

http://backyardaquaponics.com/forum/vie ... c&start=15

HaHa, it sounds like worms is head of the bathtub mafia (forgive me I'm from N.Y. and have a weird sense of humor)


-Stevo

"take these bath tubs for free............one day i may ask you for a favour........."