Just not happening

[Charlie]

Hi all
We are looking for some advice. We have had a system trying to operate for some months now. Has 200 very small silver perch that are surviving but not very active. It is pretty cold here though in SW West Aust. Nothing seems to grow - silverbeet seeds geminated but only grew about 3cm high. Also have heaps of Algae in the fish tank. Can anyone offer some solutions.

[Murray]

Hi Charlie,
Have you got the tank under cover ?
Is there direct sunlight getting onto the surface of the water ?
How does the water test for Ammonia, Nitrates.
What is the water temp ?
How much food do you give them each day ?
What kind of food ?


Just a few questions to get started on.........

[Hamish]

My guess is the Algae will be robbing all the nutrients.

Murray is right - post your water test results. Nitrite, Nitrate, Ammonia and pH.

Get a cheap min/max water temperature recording sensor - I have them for sale for $20+$5 postage if you want one. Email me or PM me if you want one.

If you get your water temp and tests all right then your fish will be happy so they eat - and make waste - and once cycled so the bacteria is all well established the plants will grow with the nutrients.

I notive my water temp is about 21.5 in the morning and the Jade perch wont eat much if I feed them first thing. But once the water warms up to about 23 by mid morning they are right into their food.

[Jonathan Dyer]

I drunk Kirup Syrup and survived!

Hi there Charlie,

Aquaponics can be a bit fiddly, but knowing the local conditions I would say that your biggest concern is the water temp is far too cold for silver perch. I know my system every night currently gets down to around 8C and I’m further north than you are but I’m growing koi and goldfish able to still grow and perform at these temperatures as well as growing silverbeet in my growbeds but they do grow slow at this time of year.

I recommend that you heat the water up by some means and depending on the size of your tank the easiest way to do so is a few aquarium heaters (3x 300w for say 2000L tank) try to aim for about 25C if you can.

At the same time your algae bloom needs to be treated straight away or possible risk the loss of all your fish. I would do a 50% water change and go out and buy some pond algae killer (a very weak solution of simazine) brought at the local hardware will fix the problem completely but double the dosage recommended and keep a close eye on it, however, if your trying the ‘Organic’ way of food production a 99% water change would be needed and some barley straw in a shade cloth bag submerged in the water will also work. Additional oxygen supply to your fish tank is crucial as the algae will supply oxygen during the day but at night will rob oxygen causing stress on the fish which intern can die, an aquarium fish pump with an air stone will help no end, if its only a small pump 2-3 would be best.

Once you have these intact you system will stabilise very soon.

And Hamish even rainwater left in a bucket with no nitrates for a week or two will start to grow algae, it is not always the presents of nitrogen that makes algae grow, yes, the more nitrogen the faster it will explode that is true but not always the case. 200 small fingerlings don’t produce too much nitrogen.

Charlie had your microbes built up enough in your system before you stocked the fish as that can also be responsible for you bloom? If they haven’t been given a minimum of three weeks to build up numbers befour you added your fish what Hamish said would be correct as the algae would grow and out compete nutrients from your plants due to an imbalance.

How many liters is you fish tank?

[Jonathan Dyer]

I double checked an algae killer product by PETS I have used in the past and the active ingredient is Diuron which works well but I have also seen products with Simazine same effect. The product is fish safe and will not affect your silverbeet or other plants, if you have duckweed/azolla growing in the same water it may affect it I’m not sure, but works great and cheaper than loosing 200 fish.

[GaryD]

Hi,

I would think twice before I put any chemical in my tanks.

There are many remedies that won't kill fish but which are banned around fish intended for human consumption.....eg...Potassium Permanganate, Formalin, Malachite Green, etc.

Your situation is different Jonathon......you're not going to eat your Koi or Goldfish.

Gary

[Jonathan Dyer]

Gary,

Whether you like it or not you have eaten these chemical residues in your life, yet they would be almost undetectable.

By the time the algae has been controlled and numerous water changes the chemical in the fish tank in a years time will be undetectable. You could drink this stuff and you wont die, it may not be good but I don’t think you will loose 10 years of life because of it.

Algae killer will control the algae bloom which is detrimental to the system and the fish and in only a few weeks time the system will stabilise. Over the next year there will be no chemical residue left in the tank due to numerous water changes and dilution as well as chemical break down. But if you don’t believe me what is your recommendation?

[Hamish]

I like the idea of the barley straw - seems like a nice healthy way. Perhaps just blocking all sinlight to the tank for a couple of weeks at the same time as placing barly straw under the return to the tank (so all the water has to flow through it) might work? Or perhaps a canister filter like the one I have set up and run the UV light for a week or two?

[notable]

hi Charlie
Lets get back to basics. A few months ago I had an algae problem, so I:
Covered the pond to stop direct light
Installed an air pump
Cut out feeding the fish for a few days
1 week later no algae
My silvers are hibernating at the moment, water temp is 12 at night to 15 by day, so I have put some lengths of 90mm PVC drain pie in the tank so they have a protected place. Minimised feeding to every second day. Adding some trout tomorrow as a short term, 6 month solution, that willl give me some minitrout fillets for summer, (see I have created a market for undersize fish),so the nutrient for the veg will continue. Adding a third grow bed this weekend.
keep at it
cheers
Rodney

[GaryD]

Hi Jonathon,

But if you don’t believe me what is your recommendation?

I have no crisis of belief around you.....but you are repeating advice that is provided by chemical companies and there is plenty of evidence to suggest that they can't be trusted.

The 'pea soup' phase of a start up invariably affects all outside aquaponics systems initially.

As for my recommendation......cover your fish tank, stop feeding the fish....and wait.

Gary