Backyard Aquaponics
A place to discuss aquaponics

Try throwing in some shell grit, rather than lime. I got my system to the desired pH with Ca(OH)2 *before* the fish went in, shell grit keeps it in the 7.2s very reliably. Even after draining heaps of water due to washing gravel in new GBs and adding about 1000l of rain water, it only dropped about 0.1pH, and is now back to its usual level.

Is there an advantage of shell grit over lime? Also can egg shells be used as an alternative e to shell grit?

If I use shell grit, do I just leave some in the bottom of the tank and will it dissolve as it needs to in order to keep pH the right level? .

Sorry bout all the questions... Why is 7.2 optimum, is it for fish health? Because I thought 6.5 was opt for nutrient uptake for plants?

You can sprinkle the shell grit through the grow beds... or hang it in a sock under a water return...

Shell grit dissolves readily... (egg shells are hard and take longer).... and is "self-regulating"...

Only dissolving when the pH drops... and ceasing once it raises beyond a certain point...

Usually.. it'll hold a system around pH 7.2 ....

My shell grit is in the GBs and the bottom of the FT & ST. Slightly more acidic might be a little better for Iron availability for plants, although mine are not showing any signs of deficiency so far, but I've read that fish have an internal pH around 7.4, so the closer the water pH is to that, the less effort they have to put in to maintain their internal levels.

Got a link Gungulla?

Not handy, but I think it is in one of Wilson Lennards publications

Makes sense thanks gunnagulla.

So the shell grit you get for chooks is ok?

Yep... that's the stuff...

Thanks again

It is on p4 in Aquaponic System Design Parameters: Basic Water Chemistry by Wilson Lennard June 2012

http://www.aquaponic.com.au/Water%20Chemistry.pdf

Well it took a little while but I'm proud to say my system now looks like one of those on the AP website. It is becoming productive, is a joy to spend time in. I spend more time harvesting than I do with maintenance, fertilising, weeding etc. it IS everything I hoped it would be. I'm hoping I haven't jinxed myself here but I'm just so in live with my system, I can't ever imagine moving house for that reason alone. Work has begun on the deck. A few photos to show my progress thus far...

Looking good Carolin... not bad for winter huh?...

Looks all good there Colours How are the aphids going? The wheat I planted seems to be a breeding ground for them, and they are in the cabbages, but dont seem very interested in the cauli or chard.
How about the trout? I reckon the largest of mine are getting up around 18-20cm long now, although I haven't netted any for a precise measurement.

Yes Rup definitely more productive than my soil garden which I admittedly have not maintained at all since AP, I hope to use it for spuds, onions and pumpkin etc, the bigger stuff.

My cauli and broccoli are not doing really well. Interesting cause they are the winter crops and apparently like salt. I know they like boron and potassium. Might need to concentrate on getting some trace elements in there.

Lettuce has finally popped up, must've needed a little more warmth.

Aphids were finally controlled by wasps, I have found many aphid shells around that have been parasitised. A definite bonus of patience with organic farming. One kale plant suffered badly and although I use a jet spray every other day on it I guess it was just susceptible so I ripped it out. The puppy loved it!

Trout are getting bigger and hungrier. I'm guessing the 200 mm mark although in one tank they are prob 30% smaller than the other. The tank they are in has no water flow (apart from that leaving in circulation) and I have had issues with my air stone. Will install a new one this weekend so hopefully they will be a little happier and hungrier.

Looks great.

Why shouldn't you grow flowers in AP. Love those little guys. They grow best in shaded areas out of frost?