Backyard Aquaponics
A place to discuss aquaponics

I wouldn't use chicken poo in AP either- at least the blood and bone has been processed with heat.

About 150 tiny Murray Cod went into my system about 11pm last night, after an hour and a half in 7ppt salinity water, and before that, an hour of temperature and pH adjustment by poking holes in the plastic bags whilst sitting in tubs of system water. My system was at pH 6.72, 24C, water in the bags was pH6.20, 26.5C. Minimal water from the bags made it into my system, I was trying to avoid the stuff my supplier had added to protect the Cod against Ammonia.

Today we had record high temps of 42C here in the hills, a degree higher than the record high of last January, and it's still over 38 just before sunset.. and 37 inside- I foresee an uncomfortable night tonight! The system water was 26.1C 2hours ago, which is fine for these fish.
I can only see a few of them in the tank, I think most must be hiding under the SLO horizontal pipe, which is covered with loose netting, to prevent them being sucked into the sump.

I also bought some 1.5mm "sinking" pellets.. where sinking = lots still floating after 8 hours! My floating pellets sink faster than that! I hope the little fish dont starve waiting for the pellets to sink... and I dont really have any idea how much to feed them at this stage, as I dont know if they are even eating them, the pellets are a similar colour to my tank and invisible on the bottom.

Good luck with your Murray Cod, Gunagulla. I hope you have the same level of success with them that you achieved with your Rainbows.

I know many fish should be allowed a day or two at least to get used to their new home before ya worry much about feeding them.

However, my small catfish fingerlings when I get new ones, are usually willing to come up to the surface to eat in less than a day (little fish can get hungry and that often overcomes their shyness.) I don't really know much about Murray Cod though.

Often to get food to sink better, smash it up a little bit. Like a hand full in a plastic bag smashed with a little block of 2 x 4 or something. Usually works to help my little catfish transition from "baby food" to the regular pellets of course catfish have big mouths and grow really fast when conditions are good for them so it usually isn't that hard to feed them.

Thanks PLJ, it will be an interesting exercise for sure! I had a good look this morning and almost all are hiding under the netting around the SLO, with one darting out every now and then. They are very fast, and only around 40-50mm long, making them almost impossible to see when the water surface is disturbed.

TCL, they have not yet ventured from the bottom of the tank and are apparently bottom feeders, I'll just have to wait and see if they will come up to eat when they get larger. There wouldnt be much left other than dust if I crushed the 1.5mm pellets, so I soaked 10g of them overnight and squashed most of the floating ones this morning, ie more than half of them, and that made them sink. I read in another thread a while ago about someone squeezing wet pellets to make them sink.


I'll probably have to do some foliar spraying, and supplementation as the available nutrients for the plants have dramatically decreased from feeding 300-400g pellets/day to just 10g now, and I dont want the tomatoes to suffer, as there is a large amount of not yet ripe fruit to harvest in coming weeks.

I'll make another batch of tomato sauce today... just as soon as I finish preserving the remaining ~15kg of apricots from my tree.

I think I've got the same Murray Cod. Sound about the same size, did you get them from a guy in Mildura?

I got mine in yesterday, and they are very shy too.

I think they need to be weaned onto the pellets after travelling, so I've got some frozen blood worms (recommended from Ausyfish), and put them in. They'll sneak out and take a few if they land near the hiding spots. Then quickly go back. So small though.

Mine are from Narrabri Fish Farm, quite a long way from Midura, so I doubt they are from the same batch!
The breeder reckons mine are pellet trained, but they don't seem to be eating much yet.

They all come out of hiding at night, and shining a torch in there does not make them swim around like maniacs, unlike the recently deceased trout, but I'm not sure how much food they will be eating at night.

Here's a graph showing how the system resisted the very high temperatures last week, having the FT and sump buried sure helped keep the water temperature down!



Unfortunately water leaked into my data logger a couple of weeks ago, making the new battery go flat very quickly, 1/2 AA, (or A battery as I asked for in the shop ) are rather expensive at $14 a pop. I've got another battery in there now and sealed the logger in a vacuum sealed plastic bag after drying it out in the sun, so I'll see how long it lasts.

What's yr average air temp Gordon? Might be an idea to get an external logger with a thermistor?

If you are worried about your nutes while your new fish are growing out, you can dose with Charlie Carp.

I have done this a few times with good results. Just not too much as you will get a good bit of ammonia from it

This month, averaged temp every minute, it is 26.5C, with a range of 14.3 - 41.8C.

I have tried a thermocouple with my off grid data logger (it can do temps as well as electrical), but because the cold junction temp is varying and different from the data logger, the temps are inaccurate.
I've spotted a remote sensor with wireless, but its way beyond my current minimal budget, so I'll stick with what I have for now if the battery isn't dead, and otherwise it will just be manual measurements with the pH, salinity, etc meter.

I picked 5kg of tomatoes today

Thanks rsevs3, I do have some CC here, but so far have only used Seasol, and my Nitrates are still around 80ppm, so I probably don't need to add any just yet... but it is an option I may use. I gave the system a few doses of peeponics in betwen the trout and cod, so that should have helped a bit.

After Wednesday's 5kg tomato pick, yesterday I dived in with a bright torch, plus did a bit of sticking my arm deep into the mass and feeling around for ripe tomatoes, and found another 4kg!

I'm suffering a bit of water loss over the side of GB#8, which has the 3 tomato plants almost all the 9kg came from, and I think the mass of all the plants hanging over the side is bending the GB side a enough to allow some water loss, probably via wicking, since they are very strong GBs and I dont think they would bend down ~75mm.
I cut the inflow rate back a bit, so the water level will run a bit lower each flood, and I hope that is enough to prevent more leakage. I'll have to try and suspend the tangled mass and ease the pressure on the side, but doing so without damaging the vines is going to be a bit tricky.
I've been making sauce with the tomatoes, capsicum, garlic and spring onions and chives from the AP plus some thyme from the dirt, and it looks like I'll easily have enough to last the year, as there are still stacks of green tomatoes to ripen over coming weeks. 23kg picked so far!

Could also be possible that the mass of tomato roots could be causing blockage of water flow through the media and causing water to flow over the media out of a grow bed. (Not sure if that is what is happening in this case but I've seen such things happen.

I've ruled drain blockage out TCL, max water level is still about 20-30mm below the top of the media in the few locations I can see it (both ends and a few spots in between), and the drain is functioning normally.

Bowls of tomatoes everywhere in the kitchen, so I'd better fire up the solar powered induction cooktop and get my next batch of sauce underway