Backyard Aquaponics
A place to discuss aquaponics

Wow! Done a fair bit of work Johny! Love the timber cladding around the system, very neat. I assume the missus is very happy with the aesthetics?

JaMa88

My wife is very happy with the new look .


Somrota

We had three days with temp over 38 and the tank temps topped out at 26.5 on the last day. So a bit more work needs to be done to keep the temps down.

Last year with the silver perch in a above ground insulated tank the temps still got over 35 in the fish tank.

So some improvement but still room to improve more.

so did the trout survive the hot spell?

yes Dan they did. A little less food taken but back to normal today.

Well my Do Probe from Atlas Scientific finally arrived today. So tomorrow I will add it to my data logger.

The first test will be daily readings for a week on the f&d as it is, then the second week I will convert it to constant flood. Interesting to see the same system with the two approaches.

Now I am in no way trying to say one is better than the other but rather which is best for my system. If I stay with f&d then I will atleast be confident that during hot days I can use constant flood to control heat exchange in the grow beds. At the moment with out test the DO I am not so confident to try constant flood.




On grow bed heat exchange, I found an interesting effect during last weeks heat. I have a temp probe set in the gravel bed at about 75mm depth. During the day you can see on the logs the flood and drain cycle as the temp on the bed raises during the drain and drops on the rise as the water reaches the probe.

We are only taking about 0.2C but in the scoria with same probe at the same depth you cannot see the fluctuations. So it looks like scoria is a better insulator. stands to reason. The other thing to note is that the gravel bed is shaded and the scoria bed is in the full sun.

Glad to see someone finally doing this comparison, I'll be interested to see what you find. I've made DO probes but never my own logger setup so it's neat to see.



I haven't worried about the DO because i know that for most systems as far as the plants are concerned constant flood works. I'm still curious to know what the difference is though.

Cheers

Hi Scotty.

It is my trout that I am concerned about. It would be nice to be confident about the DO levels. On the hot days the trout showed no signs of stress, (that I could see). It would also be nice to avoid using extra aeration if possible.

To date I have got away with one 35w air pump for the solid break down drums. Four 200L drums are fed solids from the RFF every two hours for 1 minute by pump. It takes just over a day to pass through the drums.

Currently they get the morning sun only but I still need to cover them so they do not get the sun at all.

Added eight half barrels for Basil, Passion fruit, Asparagus, Sage, Blue Berry, Mint, Parsley and finally in the last tub Punkin and Capsicum seeds.

All the tubs are filled with scoria and on the same timed food and drain. 2:30 on then 17:30 off to drain.

For those interested I managed to add the above barrels without using pipe fittings for the drains. I drilled a 32mm hole used a heat gun then forced a 50mm pipe through the hole.

The 50mm pipe has a 32mm pressure pipe as a guide with a 32mm socket glued on then that in turn is glued into the 50mm sewer pipe. The join between the 32mm and 50mm pipes is tapered with a grinder.

Now if I had that lathe that I intend to get in retirement for a steam project I could have made a better job of the drift.

Drift.


Hole made with Hole saw.


Over kill heat gun.

Drift pushed through.


Rolled lip on the inside.


Stand pipe in and a little silicone just to be sure.

Stand pipe from the inside. No silicone on the inside required.


The 50mm drains connect to the 100mm common drain the same way. In this photo you can see the nice rolled lip on the inside of this test pipe.


I must point out that this is not my idea for joining pipes but rather from a video I watched quite some time ago of a German fellow making air lift pumps. He showed this method to easily join PVC pipe. He did glue his pipes with PVC solvent cement.

You can also use a hair drier to heat the drum and pipes with. I just used my PVC welding heat gun. Normally I would make welded PVC flanges to bolt onto the drums but I required quite a few and have just about run out of PVC welding rods.

Hopefully this may help someone.

Well I had some time today to set the DO probe up and make some tests.

The first issue was the low DO of 5.22 in the trout tank. I was a bit disappointed in those numbers as I thought it would have been higher, as the trout seemed ok in the tank when it reached 26-27C the other week.

The first thing I tried was to change both grow beds over to constant flood. It ran that way for 4 hours without any change in the DO.

I then put the spray bars back in both tanks. With these bars all the water returning to the tanks gets sprayed onto the water surface. The other return pipes I took out only sprayed 30% of the return water onto the surface.

As soon as the above change was made I could see the slow increase in DO. A hour later and it is up to 6.17 and still rising.

I have also now put the system back to flood & drain. At this stage their was no difference between f&d and constant flood as far as the DO is concerned.

I do need to test this over a longer period but was just concerned about the temps over this next week. I may try constant flood again once I am back working from home late next week. That way I can keep an eye on it.

Well the weather beat me. I have just finished fishing 180 dead trout out of the trout tank.

It looks like these SA trout will take temps upto 26degC in the tank. This has happened a few times with out issue. But today they made it to a bout 4pm when it was 28degC in the tank and 45degC outside.

That last 2degC made all the difference. The DO was 6.8 when they started dropping. Now that the DO load has gone it is up to 7.33 with a temp of 28.62 and that is on the way down.

Another week and the blower would have been up and running.

Those DO readings are temperature compensated so Iam not sure just what that is. I suspect that the real DO is a lot lower. Or the other idea is that the probes detects the DO as a lower reading due to the temp then corrects it to the correct value.

Can anyone clarify this please?

impressive system is a understatement
wow the amount of work !!!
great to see
cheers b&v