Backyard Aquaponics
A place to discuss aquaponics

I have now also added a fingerling tank which was no small feat with my limited space. It is made from a 100L blue barrel and sits on top of my IBC fish tank. I redirect some flow from my existing pipework for the main fish tank (40mm) into a 25mm hose with a ball valve to control flow. Then I have a 40mm SLO to drain the water into the main fish tank below which means its flow doesn't change at any time. I also placed 1 of my air stones in the fingerling tank along with one air stone from my backup aerator.

The reason I wanted a fingerling tank is that my Jade perch have grown at varying speeds and I don't want to harvest them all at the same time due to their size difference and because I like to eat the fish fresh not frozen. I considered putting the fingerlings in with the bigger fish but I think the size difference may result in them being eaten or bullied.

Just thought I would throw in this photo from yesterday as it was the most awesome colour in the sky and the succulents on the greenhouse roof are really starting to look nice. (the flash has exposed the greenhouse a bit much but the sky in the background really was that colour.. i took the photo around 4pm i think just after a storm

I have a question for all you super experienced AP'ers out there!

I am thinking of adding Bio Balls to one of my 3 sumps.. now before you all sigh and tell me to reduce my fish numbers and/or add more grow beds (yes I mean you Charlie ) hear me out..

1) I cannot add more grow beds, there is no more room inside the greenhouse or outside.. no more room on the wall or even above the fish tank now! I am considering a narrow bed on the outside of the greenhouse which sits 20cm from a 2 metre retaining wall which I will only be able to access by ladder but that is for the future.

2) I have a lot of plants that are in towers (70 strawberry plants in 10 towers) and 3 flooded type NFT tubes with 30 holes on the other wall growing a mix of greens etc.. plus what grows in my 3 ibc growbeds filled with 20cm of gravel topped with 10cm of expanded clay.

So the reason I want these bio balls is that now that summer has rolled around and my Jade Perch are feeding like mad I am having ammonia readings and having to cut back on feed..
Now since being cycled a year ago I have NEVER had a Nitrite or Nitrate reading which I know people say is fine but with so many plants and the strawberries being fruiting plants I see signs of nutrient deficiency.
And now that I see ammonia readings which i have almost never had I believe I don't have enough surface area for the bacteria to convert all the ammonia.

The best solution I can come up with is to use one of my 600-700 litre sumps to hang bags of bio balls in

- Now what do you guys thing?

- I have been searching the net for prices.. does anyone know of a reasonably priced supplier that delivers or is in Brisbane, Australia?

- I am also wondering how many balls to get (I understand there are varying sizes so the number of litres I would need is what I am trying to figure out) also many of the online suppliers are not mentioning the surface area of the balls.. i know it is higher than expanded clay..

- Is there a best type of bio ball and advantages disadvantages to the different sizes?

Any advice will be appreciated!

Great News Tom! Glad it worked Mate,

You can try Age of Aquariums for bio ball although I think moving bed is better and use less space. I cover my DWC inlets and outlets with scoria rock to increase bio/solid filtration.

Good work
Does that mean I've earn't my 'Legend Member' status?

I too have limited space - Maybe adding more water volume will help? i.e. more buried sump and your fingerling tank - which I love!

Hiya Tom,

Fantastic workmanship in both your AP and Pizza/BBQ builds.
Could you explain a little on your choice of CF vs FD?

I like the simplicity of CF, but I wonder about the water in the bottom of the grow beds. Does it stagnate over time if the standpipe is taking water from the top of the growbed?

Thinking out loud perhaps it's possible to do CF like you have done, but instead of slotting the outer part of the standpipe all the way to the top, you could simply slot it a few inches, meaning all the drain water would come from the bottom of the GB? Of course if it ever got blocked then you would have an issue I guess, but a hole in the top of the outer pipe would fix that. (and stop it from siphoning)


Like this (excuse the crappy drawing):

Yes Mr Folly - you can drill holes only in the bottom part of the gravel guard.

Is there any advantage in doing so or is a simple standpipe enough? i.e. Do people have problems with the water at the bottom of a GB?

you dont simple have a standpipe you have a gravel guard and then your stand pipe in the middle. This enables you to clean roots from the holes you drill into the gravel guard and also remove the standpipe to drain.
I don't have trouble with it

Sorry,... I worded that badly.

What I meant was, is that an advantage to having the holes in the gravel guard just at the bottom (thereby draining the water from the bottom) as opposed to having holes going all the way up (and draining water from the surface).

Hi MrFollies,

I could imagine that it would work as you imagine it, ofcourse it would be important to make sure the holes/slots could handle the flow and that the media guard is lower than your grow bed edges just in case the guard gets clogged and the water needs to flow over the media guard top and not out over the edge of your GB.. although judging by your illustration that's what you intend to do.

As far as CF vs FD goes.. well I don't think I have been into aquaponics long enough to make a judgement call on that and as yet I have never emptied my GBs but I have only had them running for a year so I can only defer to what I have read and assumptions I have come to from that.

From what I have read the two most common objection to CF is firstly that channeling can occur (water follows same path and doesn't distribute nutrients oxygen well and anaerobic regions can occur) and secondly that not as much oxygen is drawn into the bed. I think the channeling will only occur if you are overstocking fish and your GBs cannot handle the waste that is being put into them.. also if you have a swirl or radial flow filter you will reduce a lot of the larger particles ending up in your bed.. I guess it depends on how fancy you want to get with your system.
From what I have read many people have had CF for years and when they have emptied their grow beds they have found very little in the way of sludge in the bottom.

My reason for CF is that it is simple.. there are enough pumps/air pumps/backup batteries/timers already without adding more siphons or timed pumps.. also the water level remains constant and even though I have the sump space to have FD, I don't think it is worth the trouble.

Perhaps it will depend a little on what is grown too, even with the high oxygen level in the water, some plants will not like CF as much as others.

But like I said I haven't got enough experience to say first hand which is best so can only point out what I believe are the pros and cons

I think your system will work fine with either and as long as you don't overstock I don't think you have too much to worry about

Thanks Tom,...

Does the fact that you have CF (and the fact that the roots will always be wet) have any bearing on what you are choosing to grow?

There are a lot of CF discussions around although I understand that they are often difficult to find. Usually the first question is "how does that work with no oxygen in the bed?" and the best way I like to explain is that if you take a plant and put it in a bucket of water it will live for a little while but eventually fall over from oxygen starvation, but add an aerator to that bucket and it will grow and flourish. Now in CF, you are turning over water constantly through the bed and the water your intoducing is oxygen rich so it is readily available for the plants root cells.

Ive ran CF for years and never had an issue with any plants and I just run a standard media guard. Water is drawn through the guard at all levels of the bed due to the sucking action created inside the guard and down the standpipe.



@Tom - Regarding adding a biomedia (Im not totally against it mate lol), yes you can add any kind to a sump tank or anywhere within the system if you like. As you say, you are limited with space now. You can get 1000's of bioballs for reasonable prices off the net and you can add them to a filter sock or make your own out of a laundry basket or something and literally emerse the sock in the sump. You are providing additional surface area for nitrification.

I don't grow any root crops (which is what some people say sometimes does not grow as well in the aquaponics) I grow those in my wicking bed instead. And my strawberries are in towers on 15min on 15min off since apparently they sometimes don't like the wet all the time (although when I first had the towers I had the pump on all the time and they seemed to do alright anyhow)
Like Charlie said though if you have enough aeration occurring by turning over the water often then it really shouldn't matter..

You can easily convert CF to FD in the future (as long as you have the sump capacity) if it doesn't seem like it is working for you