Backyard Aquaponics
A place to discuss aquaponics

Hi Everyone

My first Aquaponics system has been running for around two months now and although fish are healthy plants are not really growing.

I am worried the plants are not having enough time in contact with the water.

Could it be that the water is siphoning away too quickly.

Also my koi seem a bit nervous in my IBC.....what can I grow in rafts to offer some feeling of security?

Do you have a system thread or more details about your system? How long does the bed flood and how long between flood cycles? Continuous pumping or timer?

When did the system finish cycling?
What types of plants?
When were they planted? (moon phases and when seeds were planted can have an impact as can temperatures)

Most plants are happy with only brief floodings as long as they don't dry out.

What is your system pH (that often has more to do with stunted plants) have you dosed with any seasol or maxicrop for trace nutrients? What is your media?

As to nervous koi, well I might recommend wrapping something around the IBC to protect the plastic from light and also make the environment in the tank a little darker for the fish. (Shadows of you walking up to the tank probably could be making the fish react in a nervous manner.)
You could probably grow a variety of things in a raft, however remember that a raft on top of the fish tank might have issues with the fish eating the roots, or fish poo and fish food getting caught up in the roots and getting icky. Also, a raft on top of the tank might make inspecting your fish more difficult. You might be better off simply creating a cover over the tank but then the fish probably will react when you open the cover.

Well I ran the system for three weeks before adding plants and fish but must admit I have not tested anything

I have the kits for my marine tanks so will use those that can be used for freshwater

I am growing tomatoes, leaf lettuce, beans, peppers, cucumbers

I did not pay much attention to the moon phase

I am currently using hydroton and running 1hr off 30 mins on with a bell siphon

It has been very hot lately.....30 deg celsius plus everyday

With the heat you might be better off with a shorter off period with the heat.

did you add something to first cycle the system in that three week period? before adding fish and veggies?

Hey sorry for the late reply......

still struggling. My water has now turned green so did a big water change.

I will test the water tonight. I am still worried that the roots of the plants have no contact time with the water. Once the water starts draining the siphon works really fast.

What should I do?

Hi ya..
the water turning green is a sign that something is happening.
Commonly called 'peasoup'... you can add more covering to reduce light entering the water, but I figure it is more to do with alge
having ammonia & light (nitrification) so nitrate available for food to grow.
The best way to counter this is to draw out more nitrate and having bio filtration is part of this.
IMHO only, doing a water change will only slow down the system from cycling.

+1.... shade and pump....

Water changes will only slow your cycling....

my problem is the electronic timer on the pump only allows 8 different times a day. I have it coming on for 1/2 hour every hour ie. at 7 - 7.30 then 8.30 -9

It does not run at night

So it fills up the container quite fast and then the siphon drains away so quickly and well that for most of the time the pump is pumping and the siphon is just draining all the water away without letting it refill

I have put a cover on the reservoir

If you are not cycled yet, you might think about running the pump constantly and pulling the bell off the siphon for part of the day if you are thinking the plants are suffering from not getting enough water.

Myself, I would get a mechanical timer that I could set for 15 minute intervals the clock round. that way you can set it to run 15 minutes every hour or perhaps even run it 15 minutes on and 15 minutes off until your water tests say that you are cycled, then you could reduce the pump cycles a bit after that. Running only during the day and minimal pump cycles is not so good for a new, not yet cycled system.

For now I would just probably pull the bell off the siphon and let it run constant flow/constant flood until you get get a timer that will work better for you. Of course this only works if the pump is not so powerful as to over flood the bed and gravel.

Fair suggestion TCL... and agree that you need to get a timer with more on/off cycles...

If the pump is too powerful.... try cutting in a "tee" just after the pump... and return some of the flow back to the fish tank... add a ball valve for control, which means you can also turn it off later...

This will help oxygenate your tank as well.... which will also help with the algael problem...

Ok water cleaned up a bit but still very green.

What I see happening when the bell is in action is that it drains so well and reaches an equilibrium with the pump where it cannot fill up again as there is a constant siphon

How can I stop this siphon? ie. by making a bigger hole in the inner tube intake?

I added some more plants with bigger root structure so hopefully this should help clean up the situation

This is very common: the siphon sucks the growbed fairly dry, but does not quite stop before inflowing water allows it to start again. What you need is a way to break the siphon reliably. This is usually done with a small air hose that leads air from a cm or two above the low water mark up and into the top of the bell. This should help: viewtopic.php?p=153279#p153279