Backyard Aquaponics
A place to discuss aquaponics

nice solve!



form here... http://www.ehow.com/facts_7638897_disso ... -work.html

Galvanic Sensor
A galvanic sensor acts as a battery and is able to generate power without external voltage. Galvanic probes contain an anode and cathode in an electrolyte. Oxygen enters the electrolyte via a membrane, which generates voltage between the anode and cathode. This difference in potential voltage is used to measure the amount of dissolved oxygen.

Polarographic Sensor
Polarographic sensors operate in a fashion similar to galvanic sensors, but require a connection to an external voltage source. The difference in voltage potential between the anode and cathode yields a measurement of the dissolved oxygen.



Read more: http://www.ehow.com/facts_7638897_disso ... z32GuNberC

It works for now but I may put an electronic isolator in place. From the information supplied by Atlas scientific it looks like it is not probe to probe interference. But rather probe to environment with the DO probe helping it along.

They have a voltage isolator that can be used to isolate the supply and serial bus for both probes via the multiplexer board I am using. That shows the probes work together ok.

For now it is working ok. I might try a voltage isolator to see if it makes a difference over the mechanical isolator.

I prefer your PVC solve.

Much more creative.

It's also one more thing to show people, when you're showing them how your other PVC contraptions work.

"Look Mrs. Bullwinkle! Then this bit of water gets isolated from the rest of the system for a few minutes while the test is being done! Want to see it again?"

Ah yes but suspect it is still having an effect on the readings.

BullwinkleII

As I suspected the mechanical isolator was not doing the full job I purchased the voltage isolator from Atlas.

I first tried to use the isolator to isolate the power, serial and data lines to the multiplexer board that controlled both probes via one serial port. The result was similar to the PVC isolator eg DO 20 and PH around 5.5.

I then gave up on using only one serial port and ditched the multiplexer. I now have the DO probed power and serial lines electrically isolated via the Atlas isolator and the PH probe on its own serial port without isolation.

And that there is the fix PH of 6.8 and DO in the range of 10.3. Numbers I can live with.

So anyone using the Atlas Scientific DO and any other probes you need to electrically isolate it. That may be the same for other brand DO probes.

How do you isolate it?

Is it using another arduino board? Or just a different power supply?

Hi Colum

With one of these. For that price it is not worth making.

https://www.atlas-scientific.com/produc ... r-iso.html

Hi all. Just a warning for those using the Atlas DO and PH probes. When I read that the probe could be submerge for prolonged periods I took that quite literally. Up until a month ago I had both probes submerged about 500mm deep.

For the last month they have both been floating in a raft on the water surface and now I can report both read correctly. This is why my testing worked in a shallow bucket but resulted in false readings in the fish tanks.

Talk about stupid ideas.

Hi all

Just got back from a two week driving holiday/work to the Gold Coast and the best part was looking at the growth opon our return. Only one issue the Artichoke grew so much that the new fruit has put it on a lean. Fixed with a few star droppers down the outside of the barrel.

For those that leave friends or family to look after their systems I can recommend measuring the fish food out before hand and marking each feed. I decided to reduce the feed for the two weeks by 50%. That worked out well as I know of at least two separate daily feeds missed then caught up the next day each. That prevented over feeding.

Fantastic system - so many great ideas to steal! Well done! How many trout now, and have you got a conclusion on temp differences from flood and drain to constant flood, next year i hope to beat the heat too.

Steal away as many ideas as you like. In my opinion flood & drain will heat the water up quicker when the air is hot so on very hot days I remove the bells. By keeping the water lower in the sump over summer I think it helps control the tank temps. So that puts the sump water between 1 - 1.5m below ground.

Yesterday we had an overnight low of 10.5C and a high of 34C during the day so a 33.5C rise in temp during the day outside near the tanks. But the tank temp were 17.5C overnight and a max of 21C during the day. So a 3.5C rise in the tanks during with the system running in Flood & Drain all day.

I still need to do more on cooling for the hot period to come in the next few months. A shade house is going up soon to help keep the sun off the system and plants.

Currently I have 82 Trout > 0.26KG and 100 fingerlings in the other tank.

Hi Johny5,

I have been catching up reading a few systems threads and I found yours very interesting. Great job so far

I agree having as much of your system water in the ground is a good thing. keeping temps down during the hot summer is much easier and volume stops those temp swings too.

Summer sun is a killer here too. All my grow beds need to be under shade to reduce the heat exchange between grow beds, sumps and fish tanks.

Looking forward to seeing how your system progresses and related water temps.

God bless, froggo.

Thanks froggo.

For Dan
The drum on the left is the RFF with the sludge pump to the right. The blue drum is the digester. A small amount of sludge is pumped out of the RFF every 6 hours and into the digester. An air lift keeps it agitated, with any thing small enough to filter through a shade cloth screen making its way back to the grow beds.

It basically is keeping large solids away from the grow beds. The digester is alive with worms that would have spread from the grow beds originally. So the worms would have made it into the sump then pumped up into the tanks and onto the RFF. Sucked up from the bottom and pumped into the digester.

Live as a worm and travel.



Just for fun the Trout at feeding time.

How often do you have to clean out the digestor?

Or do the worms do all the work for you?

Hi Colum

I have not yet cleaned it out. The prior setup had very little in the way of solids and sludge in them when i Decommissioned them.

It should be good for at least a year but time will tell.