Backyard Aquaponics
A place to discuss aquaponics

You're on the way... nitrites are showing.... patience... watch for the ammonia to fall to zero... the nitrites should do the same shorty after... and then the nitrates will rise... and your plant go.... bloom...

This is quite exciting!


Also, owing to an issue with my siphon (namely I was trying to 'improve' it) I am running a bit of a constant flood bed.

I have put some air stones in there running off an air pump - will that provide sufficient O2 for my plants? Or is it necessary to have the drain cycle for oxygenation?

I know some others are run in constant flood, and I was wondering about the O2.

I have another question that relates more to a future setup that I am planning in my mind.

It has to do with the bacteria.

If I was to overflow from one bed to another (for example a media filled bed that emptied into a raft bed) would there be enough nutrients for the raft plants?

I imagine the answer to this question lies somewhere in the number of fish and the volume of media bed to fish tank ratios?

Further question; If I have strawberry towers that are fed straight out of the fish tank, with water trickling down the inside that then drains into a media bed would the towers have had enough time to convert the ammonia to nitrites and then nitrates for the strawberry plants? Or would I be better off with some sort of bacteria drum setup that then feeds the towers?

I have seen some people run their fish water through a bacteria drum, either filled with bio balls or with some other material with massive amounts of surface area to get the nitrites and nitrates going, but I was wondering if this simply provided additional filtering/converting, or if it was required in some setups?

If there is no simple answer then I quite understand, but if anyone has done something similar that has worked (or, just as importantly hasn't worked!), then please let me know

Both your strawverry towers.. and any raft(s).. will provide some level of additional nitritification....

And yes... normally.... any raft systems... ( or towers for that matter).... are either pre-filtered... or have solids removal...

Ultimately... in comes down to.. your need xx amount of feed... (and wastes)... to feed yyy number of plants....

The plant growth.. and growth rate... will reflect your nutrient availablity....

And here is this morning's test (has anyone else been having issues with the site?);



I think the ammonia has spiked because I put a wee little bit more humonnia in the other day that I thought was properly cured, but now I don't think it was

No more ammonia.....

Haha the old humonnia trick. Once your system has cycled and your grow beds are going mental, if you have a nitrate reading then you will have enough nutrient to grow more plants.

I would expect that if you look at the water you will always find ammonia, nitrites and nitrates present, no matter where you took your sample from. Obviously more of the first two at the start of the GB than the end, but still there. So it isnt a matter of having enough grow media in your strawberry tower to convert the ammonia to nitrite to nitrate before the water drains, but having enough media in the whole system to handle the load of the fish. That is why you are able to run a DWC system with no media, the conversion is happening in other parts of the system where the media is present.

If you take a sample of water from your fish tank and from the drain of your grow bed you will see almost no difference in the readings if it all. Especially in a small system with a small grow bed where the residence time of the water is not long in the case of CF.

Hi Sick pupies we have another one of those plastic kiddies pool shell / grow beds at our place if you want it. We are at Beerwah. Send a PM if you want it. I'll drop over to the coast or you can come and get it.

No, definitely not!


I thought it would be ideal to; a) Convert all ammonia to nitri/nitra by the time it hit the plants to maximise the uptake, and b) Have the plants remove all the nitrates before the water returned to the sump/FT to have the cleanest possible water.

Understandably this is going to be difficult to achieve in real life, but as guiding principles do I have it right?


Thanks for the offer, but I have another couple floating around still. I bought them at Bunnings ages ago when they were on special.

I don't imagine they are going to last years, but if I get 6 months I will be happy enough.

Edit: Merry Xmas!!

This morning's test (I think I have some Nitrates?!);

Patience... your nitrates aren't going to do much untill your ammonia drops to zero...

Hence no more ammonia, huh?

Is this just for cycling? I would imagine that there will be new ammonia introduced once I get some fish in.

Speaking of which, I should start to consider what fish to get.

As this is only a test scale unit, and my total volume of water is quite small, I would need something that can handle a) temperature fluctuations, and b) given I am in S E Queensland during summer, something that can handle 20+ and 30+ degrees C.

Not overly interested in eating the fish so am thinking goldies?

The amm is being converted to niti then nitra hence the drop in amm through the cycling process.

Yep, go the goldies.

the nitrite to nitrate part of the cycle is slowed by high ammonia levels. that's why you need your ammonia at 0. in a mature cycled system you never really see an ammonia reading as it's produced only in small amounts and converted to nitrate almost as fast as it hits the water.

you're almost cycled but adding the hummonia has actually delayed your cycling

If what you were describing was to actually happen, then your water in your fish tank should be reading zero ammonia and nitrites. Even in my system now which has cycled, if i was to add enough ammonia to be able to measure it and tested the water draining from the grow bed i would still see an ammonia reading. It takes time to convert to nitrites and then to nitrates.

The short story is, as long as you have enough media to support your fish load, you dont need to get strung up about where it is in your system. If you only need 5L of media for your strawberry towers then that is fine and the plants should do just as well as if they were in a large grow bed. If you want to have a barrel full of media and no plant growing in it at all, and just have DWC then that would work fine too.