NLD wrote: 1) I did test the ph last week and it was about 7.6.
That's good, your pH is ok so we can rule that out for now
NLD wrote: 2) We fill up the fish tank from tap town water (could be bore water it is hard water). We do have a softener on the house water so I would assume that this would effect the water. I refilled it today - the fish should be happier!
hmm... I don't have much experience with bore water. It could be lacking oxygen, calcium and magnesium. (water softening is the removal of calcium, magnesium, and certain other metal cations in hard water.)
Definately try add more aeration of your fish tank, particularly as you are running continously flooded which can already suffer from lack of oxygen (refer page 5 of this thread: viewtopic.php?f=8&t=20008&p=432353&hilit=bore+water#p432353)
Perhaps someone else can chime in here - could softened bore water be having an influence towards NLD's growth issues?
NLD wrote: 3) The system has been running for about 12 months here in Karratha. We have used the system and clay balls at our previous home for about 18months. (It didn't grow very well there either and that was a flood and drain, one grow bed above the fish tank).
So the system should be stablising by now and you should be seeing some good growth.. but you're not.
NLD wrote: 4) Basil has grown the best so far. Celery has been ok too. Tomatoes, Capsicums and chillies grow ok, however we are usually able to harvest about 10 of each (if that) before mealy bugs destroy them. I regualrly used a garlic and chilly spray to try and deter them to no avail. I have also tried to grow parsley, coriander, sage, oregano only to have them all die. At the moment there is a pumpkin and sweet potato vine growing. The pumkin has flowers at times, but these never develop into fruit.
It's likely you are deficient in Potasium, which is required for fruit growth.
NLD wrote: 5) Ooh a technical question! I do know that there are two airstones in the fish tank that we bought from backyard aquaponics. The pump... it is an aquacare WH-4000, 240V, 50Hz, 30V, 2200L/h, Hmax 2.1M. I hope that makes sense to someone!
Sounds like your pump should be sufficient for the system of your size, and you should be getting enough water turnover with this pump. But can you confirm you are running just one pump in this system? I'm still confused how your system is setup to run. Post a diagram if possible.
NLD wrote: 6) The growbeds are flooded to just below the clay ball surface. I will adjust this ASAP to about 4-5cm below.
Yep. As long as the surface of the gravel is dry, that's the main thing. Those plants need to breathe!
NLD wrote: 7) We are feeding the fish 3mm pellets that I bought from Backyard aquaponics. I feed them a small handful each day. They may even be a little bigger now  more like 30cm.
We can now rule out the possibility of dodgy/poor feed.
NLD wrote: 8.) The growbeds would receive at least 8-9 hours of direct sunlight every day.
That's fine, and will be great in winter. Judging by your location, in your fierce hot summer, like ours here (commonly over 40+ deg celcius), your plants would benefit from some gentler, filtered sunlight. Can you add some shade cloth over the top? Our vegies really benefited from shade cloth, and significant, better growth resulted. If your plants are getting absolutely fried in fierce summer sun, they will be stressed, and focusing their energy on merely surviving, therefore won't have much energy spare to grow well.
NLD wrote: I also added a good squirt of seasol to the fish water today. I have some eggplant, silverbeat and marigolds that I want to plant, however am relectant to do this until I get this sorted.
Seasol is good, but contains only very minor quantities of Nitrogen, Phosphorous and Potassium (NPK: 0.10% : 0.05% : 2%)
You could try supplement Maxicrop instead, which has slightly more potassium (NPK 4.6 : 1.2 : 3.1) and other trace elements. It's hard to overdose this stuff, so try adding 1 cup or so per week or more, see if it helps.
At this stage I suspect your plants are deficient in either one of more of the following:
- oxygen (so lower flood level and add airstone as discussed. I'm sure your layout also could be improved to increase oxgenation of the water by utilising gravity better and splashing your drain water onto the surface of the fishtank)
- fish. You need more fish as you are understocked. And feed them twice per day if possible, as much as they will eat in 15 mins.
- gentler sunlight required. In the plant world, vegies are generally very soft and delicate compared to other species, they need protection
- Potassium (add Maxicrop, "Eco Fungicide" (http://ecoorganicgarden.com.au/products ... fungicide/ plus do a search on this forum on it), or Potassium Sulphate (NKPW 0-0-50) for fast effect if you can get hold of it in your area. But try rule out the the other points above first before worrying about Potassium.
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