Backyard Aquaponics
A place to discuss aquaponics

Just wondering how many goldfish I should have in my little system? I currently have 11 small goldfish. I am using a 300 litre bathtub for my fish tank and a 150 litre pond for my grow bed. The growbed is filled with 60 litres of hydroton. Growth has been very lack luster and I can't work out what I am doing wrong. I either have too few fish or I am feeding them too little. I have been feeding the fish once a day about 2 pellets of premium goldfish food each which I crush slightly. The system has been going since early October 2012. Any suggestions would be welcome. Plants in the dirt garden have been out pacing the aquaponics system by several weeks which is a little disappointing.

I should add I am running the system as flood and drain. It floods and drains every 3-4 minutes.

Still struggling with this system. Topped up the fish tank last week with tank water and for the next two mornings there was a dead fish. Now 9 goldfish. I think I added too much water at once. In future I will fill the growbed with water and then let it sit for a couple hours before turning the pump back on and fill the fish tank one growbed full or water at a time. Filling a little water more frequently rather than a lot less often.

Apart from that my other problem is that nothing seems to be growing. Plants are staying alive but not growing new leaves. I am wondering if I should have more fish. Perhaps I am not getting enough nutrient into the system. Will do some water tests.

Switch to native fish food the gold fish food is lacking your plant requirements. Have you been adding some seaweed extract to help the plants as well.

I would not add any more fish.

Thanks ccBear. I wondered if the food might be the problem. The man at the aquarium assured me that it would be suitable for aquaponics but really what would he know - aquaponics is not his business, fish are. About once a month I have added either some worm "tea" or seasol, probably not often enough though.

I've recently restocked my system with trout after leaving it run with no fish for several months. I'm having trouble though with keeping my pH up. It keeps becoming too acidic. i have buried some shell grit in the growbed which consists or Hydroton and added small amounts of bi carb soda to make it more alkaline but several weeks later I am back to where i began. Can someone explain what I should be doing or where I might be going wrong? I'll go take other measurements to check nitrate, nitrite and ammonia. My last water test was several days ago and my nitrates were very high nitrites were ok and ammonia was 0.25 ppm down from the previous test.

I have the same problem - acidic growbeds around 6 to 6.4 (shell grit in bags)

I add hyrdrated lime in small amounts, but I've read that you have to also add potasium bicarb, which I can't find anywhere here.

just tested the water again: Nitrites - 0, Ammonia - 0, Nitrates - heaps and pH between 6 and 6.4 The plants are not growing because of the low pH and so I can't get the Nitrates to go down. Help

I found potassium Bicarbonate at the hardware store labeled as Eco-fungicide and added this in small quantities over a period of days to bring my pH back up to around 7. My plants still don't seem to be doing much though. I now have 3 trout although 1 is not doing too well. It didn't feed yesterday and seems to have some white spots on it. Not sure what to do about the sick fish.

As in Ich?
You need some more pictures as they tell a thousand words.

Pool salt is what you need to add - the recommended dosage for fish health when they get Ich is 3 parts per thousand liters of water.