Backyard Aquaponics
A place to discuss aquaponics

All sounds good to me Murray.....

But I'll leave it for Steve to add his thoughts.

Steve, where are you ????
Murray

Sorry Murray,

Been digg'in a hole............................

Thought it was about time to stop being a master of theory and get me mine own system (i'm the one with all the parts and no time)

Really i was just going to waffle on anyway. like i said, a cycled systems end products will naturally shift the ph downwards over time. so it looks like you are right.

Give me some details on your system,
how long since the fish have been inside?
Is the pot with the gravel the only media in the system or have you had the water flowing over gravel beds as well?
so you still have salt in the system? how much did u put in and how much water have you changed out since?

Steve

Thanks Steve,
Hope you can get your system up and going soon.
Fish have been in the tank now for 4 weeks - there is approx 35 Jade Perch most of which are growing very well, although some don't appear to be getting any bigger. I have had one death today, but that is the only mishap since my major fish kill on May 3rd.
The fish is not dead yet but it is swimming around lop sided , so I guess it won't be long.
The 300mm dia pot is the only media in the system.
The temp in the tank is between 20 and 23 deg all the time now.
Over the last week I have added 4 tablespoons of Aquarium salt, one per day. In a 200 ltr tank that is not much???.......

Murray

Soundls like its a go, Murray.

VERY important, DO NOT remove that pot from the system as it now houses the majority of your beneficial bacteria. An its probably struggling with the number of fish you have. Set up your grow beds as soon as possible with media, but MAKE SURE that pot is still in the system. Probably the ideal place for it is under the "return" pipe from your grow beds.

That way more bacteria can start establishing themselves in the growbed media while the ones you have in the pot keep on working.

Once again, do not remove this pot, as you will probably kill all your fish with in a day or two.

I'd probably keep changing out 10% water as you have been and putting in a new table spoon of salt after you change out the 10%.

You have probably cycled quicker due to keeping the temps around the 20C mark, but the growth in the growbeds (bacteria) will be slower because of the cold weather.

I hope i haven't confused the issue. Any questions please ask.

Steve

Last night we had a storm here, very unseasonal, power went off, lost air to my tank.....very bad........
I have a 12 volt pump pumping via a filter system and the overflow aerates the system. 12 volt battery is an old battery from my ute which obviously does not have much of a charge in it, so the pump obviously did not run for long after the power failure.
12 volt battery is trickle charged from a 240 volt battery charger.
Lots of fish in small tank .......... this morning DEATHS !!!!

Observations..... Have a top class system ... I would be really upset if this had happened when I had my system running and my fish were close to harvest. Need good quality gear on my tank ...waste of time, effort and fish to be using rubbish equipment.
Imagine if the power went out for 24 hours ... which does happen during the summer storm season here in Qld. Without a good 12 volt system to run pumps, bubblers etc..... imagine how bad that would be...

Obviously if I had been more "on-the-ball" I would have gone down to the shed after the storm and checked things out....but I didn't give it a thought... I think it is called "experience".

Those who know something about it..... note the very fat bellies on some of the Jade Perch..... is that normal..... or were these some of these obese school children we hear so much about.

Murray

Bugger....! Condolences Murray.....

Yes, it's a shocking lesson when you have deaths, especially many deaths, I'm assuming that you lost them all?

I have a backup generator on standby for my systems, this may not do me any good if things go wrong in the middle of the night though, I guess that I've just been very lucky in that aspect, whenever the power has gone out for any length of time it's been during the day and I've just whipped out the little generator and started it up.. This has been very cheap insurance considering that it's only one of those $99 GMC generators..

Though after seeing your deaths I'm starting to think that I've been incredibly lucky to have my fish survive for so long without any automated backup plan. Might be time to go get my battery, inverter and trickle charger for the bubbler, rather than just having the bubbler plugged into the mains...

Can't help you with the shape of the fish, as I'm not used to jade perch.. Why, have you been feeding them junk food and letting them sit and watch tv all day...?

Thanks for sharing Murray

Hi Earthbound,
No have not lost them all, still have about 20 that look just fine....funny how some die and others do not.....This morning when I discovered the problem there were several fish swimming around gulping at the surface .... they recovered in a matter of minutes once the pump was started again.

Another question, does anyone know why there would be a large difference in the size of these fish ? all purchased on the same day and roughly the same size when purchased.....some are growing very nicely and others are not.
The little mongrels might just have a tv set in there under one of those house bricks.... I'll go and confiscate it right now !!!!!
Murray

I've not seen such dramatic size difference Murray, but I've never had a batch of fish quite so small, and I guess it all makes sense from what I've heard. When fish are young they are size graded on an almost weekly basis. I guess when they are so young the amount they eat makes a big difference to their overal size.. You end up with the smaller ones missing out on feed as the bigger ones grow bigger, the problem gets worse as the size difference increases..

Well, I say the problem gets worse, but this is a matter of opinion in what you want from your fish and your system. If your a fish producer who is selling fish and wants them all sized evenly, and growing evenly at maximum capacity, then this isn't good.... If however your growing some fish for your own food, then it's good to have different sized fish, you don't want 100 fish all ready to harvest at exactly the same time, and all the same size. It's handy to be able to pluck out the biggest to eat first, leaving the others to grow some more, spreading the harvest over time...

Sorry to hear about your loss Murray

Murray,

I think the jade perch have a much rounder shape than the silver perch. check out the side by side pics on http://www.ausyfish.com/australian_perch.htm

I was also re-reading this whole tread from the start and i can believe that i missed out on something you posted after your first fish deaths.

You had 40 odd in 200 litres? We all went off on temperatures and ph and stuff. I can almost guaranteee the deaths, both this time and last time were from the air pump going down. (Did you even have an air pump fitted the first time?

I lost 22 of my silver perch when the power went off for 6 hours. and they were in 200 lt as well. so i'm not surprised about 40 in 200 litres.

This is a VERY high stocking density as far as dissolved oxygen is concerned. you will need to be able to GUARANTEE 24/7 airation, or drop the density way down to like 10 per 200 lt.

Sorry i didn't pick up on this earlier.

Steve

Thanks Steve,
I am absolutely certain you are correct on the aeration.....as I am learning....... I think the stocking levels are being taken care of automatically ...have too many....some will die...

I am not too bothered by this latest episode as it was immediatly apparent what the cause is/was....

I am a bit premature in getting my fish anyway as I am yet to build the "Greenhouse" to house my Aquaponics project. As the fish grow it is going to become more urgent/problem to get them into a bigger tank and I really don't want to do that until I have built the greenhouse and it can be done PROPERLY.....no more half measures !!!.

I am now more determined than ever to have a very, very good quality 240 volt to a 12 volt battery bank to run my setup. Must have good quality equipment otherwise there will be too many disappointments along the way.

I just hope other newbys can grasp the importance of aeration by reading about my adventures

Murray

Fixed the link in the last post.

Murray, i smiled when you said you were a bit premature in getting the fish. So was I. I just found it so hard to find a place to get them that i JUMPED when i found some. Now through one mishap and a long period of "having no time" i'm down to 13 of my original 66. I hear ya

Just be aware that 20 in 200 ltrs will still require constant air when they get a little bigger (maybe even now, if they were gasping) My 20 were about 3 to 4 times the size of yours when i lost them

Steve

Murray, I really feel for you

My better half always tells me to settle down and do things right before i leap in and just do it blindly. On the recommendation of you and others, I have now got the book and dvd and my family haven't heard a word from me sice I got home from work. Anyway, I am determined to set it up fully before adding any fish... time will tell if my best intentions are what actually happen!!!
Murray, you can at least have a lot of tasty jade perch to look forward to. I ate some on the weekend that were farmed, just cooked in foil on the barbie, lemon salt etc... VERRRRY tasty. Note, these fish were purged for 5 days; seems like this is very important to get rid of any pellet/muddy taste that may be present

Are you guys purging fish before eating?

Monya

I haven't eaten any of my silver perch as yet, I ate the Barra that I grew without any purging at all, and everyone who ate them thought they were great.. I think whether purging has to be done can depend greatly on the fish species, diet and water quality.

I plan on giving it a good side by side taste test when I harvest some of these silver perch, purge some and don't bother with others, it will be interesting to see the results. I'll do it when theres other people round for dinner so it's not just my taste buds, and before too many wines have been consumed....