Backyard Aquaponics
A place to discuss aquaponics

Hi Guys,

Firstly i'd like to say thank you to everyone who contributes to this forum and the awesome resource it is! Also thanks to the guys are BYAP for their advice in getting my 1000L FT and 500L grow bed system up and running. After three weeks i've just detected my first amount of nitrite 1ppm and 0.25ppm of nitrate after the ammonia running up to around 1.5ppm for a week (i haven't fed the fish for 4 days as a result). The PH has been stable at around 8. I've lost a few goldfish and recently a couple of trout that were added to the system a week ago but I'm hoping its not much longer before the system stabilises. It's strange though that the day after I added a bunch of plants to the system the bacteria seemed to kick in overnight? does anyone know if the nitrites, nitrates could have come from the plants and their root system? also I'm thinking todays rain on my exposed growbed may have been responsible for one of the trout dying..i'm assuming the rain would be at PH 7 ? do you think the sudden influx of ph 7 rainwater could have done this?

any comments and advice would be appreciated.

thanks guys!

I can tell you that I have tried trout twice and they died both times. They need very cold water to survive. Do you keep track of your water temps? At about 68'F or 20'C the trout will start dying because the warmer the water gets the less oxygen saturation is in the water. You can alter this if you provide and extreme amount of oxygenation to the water, bubbles, airstones, recirculation lines,etc...
But it's a gamble anytime it gets above 68, but some have pulled it off!

Thanks kevyrev. Water is sitting at around 21 during day and dropping to about 18 overnight. Tank is under grow bed and has a cover. I'm running air stones and have system running full time to oxygenated. They seem pretty good considering system is going through cycling. Perths going into winter so should only get cooler too.


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Hi greenhorn,

It sounds like we have the same (or very similar) systems and are relatively in the same location i.e. Perth (I'm SOR just a few minutes drive from BYAP)

My system was installed by me on 19 February and fishlessly cycled until I added 20 rainbow trout fingerlings (from Gavin at Ferguson Springs) on 27 March. I use only bore water and whatever falls from the sky. I don't have any air pumps or blowers, running my water pump 15 on / 45 off. Fish are fed three times daily. I haven't experienced any problems (touch wood).

Have you been keeping an accurate and complete record of your system? If you haven't then you wont know what is changing and what is "normal". Have you tested the water source (tap water, bore water, rainwater etc) against the system water? If you're using tap water to fill or top-up, are you allowing the water to off-gas any chlorine before adding it? Does your water contain any chloromine or other nasties that might have affected the goldies and the trout?

As for the rainfall affecting the pH, you must have had a lot more rain than me because my system level only increased by 10L or less (limitations on my measuring system). If your system water level suddenly jumped up by a larger amount then I'd be guessing that you are getting run-off from somewhere (nearby roof, guttering, overhanging trees etc) and that might contain some nasties which could be affecting the health of the fish.



All of my plants were from seed, but I'd doubt that adding plants would be the sole cause of beneficial bacterial colonisation. Maybe the timing was fortunate.



If you want to chat offline then feel free to get in touch.




Scott

Hi GH, Ill help you with your Q's


Not really - The nitrogen cycle is a development of bacteria through the breakdown of fish waste (ammonia) which is converted by nitrosomonas to nitrites which is then converted to nitrates by nitrobacter bacteria - which is basically the process you are going through now. I suppose amm could be introduced through fertiliser that may be in the soil that the seedlings were in but the it would only be trace amounts and insignificant.


I have experienced this before after a rain but never really figured out what happened - maybe intoduced something from water run off. I wouldnt expect that the PH difference would be the issue as it would not be a big change is it would be diluted quite rapidly.

Hi Greenhorn,
My advice in the event of fish death.
Test levels of pH, ammonia and nitrite- temperature.
Add salt at least 1ppt or 1kg per 1000 litres this will alleviate nitrite issues (strawberies don't like salt though)
and up to 3ppt is safe to use to dealt with other fish issues such as disease.
Have you got an AC/DC air pump in the system. Can you post up pictures?
We always wash the soil of the roots which ensures that any fertiliser is also removed. (Hving said that I know of thers that add the whole seedling, media and all and don't was, it works for them)
Many, many people around Perth top up their systems using our scheme water, without issue. Chlorine off gases in 24 hours, it breaks down in sunlight, anyone with a swimming pool will tell you that.
Don't make too many changes at once, fish don't like it. Good luck and keep us posted.

Thanks for the brilliant feedback guys. Clarified a few things for me. As I didn't fill the tank enough at the start I have put a few containers (50L) or thereabouts of water ( after letting chlorine off gas) a few times which seemed to coincide with fish deaths. Perhaps the scheme water contains chloramines?? Well hopefully all goes smooth now. Hey bunson what software are you using to produce the graph? I have kept track of the levels from day 1 so would be cool to see it graph as you have done. I'll post a pic or two soon of the system. Cheers


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Nice graph bunson, gives me ideas of doing my own!

Excel file attached in zip






Scott