Backyard Aquaponics
A place to discuss aquaponics

Hi all,

My name is Michael and i am new to the site and I have a few questions! My system design picture is attached.

1. I have had a 3,200 litre koi pond in my back yard for about 5 years now and I have just recently added 2x ibc (700L) systems with grow beds 1.0x1.2m and about .3m deep. So i have .72m3 of grow bed and 4,600 litres of water how many kg of fish would be recommended to sustain the plants?

2. My water was already "cycled" but when I added the systems my pond water went milky or cloudy. Is this just the system settling in? It has cleared a little now but is still a little dirty which is part my next question

3. I opted to use orange pea gravel (local here in western Australia) instead of clay balls because of costs. Does anyone have experience using this and how long it took for the water to come clear?

4. I am flooding for 30mins and draining for 30 mins mainly to keep everything oxygenated and for the aesthetics of the pond fountains. The drain time is around 15mins is effectively it only has 15 mins dry time is this enough?

Thanks in advance for taking the time to ready and reply![list=][/list]

Hiya Gaffa, welcome to the forum.
Interesting set up, 2 pumps, 2 fish tanks and 2 grow beds.
I use the same gravel as you, the 20mm grade and the cracked gravel. Both work ok but is heavy so I mixed clay balls to offset this. You would know when cleaning the gravel prior to adding to the gb there is lots of dust, the fines will settle in time.
Depending on fish and feed you’re looking at about 20 cubic litres of media per fish and this will include your koi in the pond.
Your pond on it’s own, if stocked, could sustain the plants. Why the extra fish tanks?

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Skeg In The Hills.

Thanks for the reply, my pond is a feature of my backyard and houses the koi. I started aquaponics to help control algae in the koi pond but also to be able to grow vegetables and produce fish for the table.

I just wondered seeing I have 4600 litres of water would basing my fish quantities on grow bed litres alone be too little as the fish waste be more diluted as opposed to only having 1400 litres in 2 ibc tanks.

While what you say in that the ammonia parts per million in a lower stocked larger volume pond would be lower than a higher feed rate stocking density or small pond, all in all the bacteria are going to do their job and convert the ammonia to nitrate and while in any one litre of water your tested parts per million will be lower, the same ammount of nitrates will be available to the plants as the water circulates (given correct flow rate etc.)
The benifit of the extra water volume would be that you would have a buffer to realise any problems are creeping in (like too much ammonia not being converted for example) as the levels would not be toxic to the fish until the ammount of ammonia was higher than that of a smaller water volume.

Interesting set up mate. Yes, the system is settling in. I had a similar issue few weeks back with the new system but eventually it sorted out on its own. Took time though, around 4 days.

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https://www.hod9.com - Hod9.com