Oakhurst Aquaponics

[Oakhurst Aquaponics]

Some of you might be interested in the unique aquaponics system we have created.

We are currently working on developing this system into a kit to facilitate year-round, individual-scale food production anywhere in the temperate zone.

[andrew namiki robert]

and that will be the last we ever hear from them,

[barry hocking]

This has nothing to do with Aquaponics Plain and simple. Aquaponics is a very fine balance between aquatic animal or fish, vegetable, bacteria, fungi and several other life forms. Not to put too finer point to it all it makes no difference what the bacterial count is if there is nothing to process it like the fungi or nematodes. It has been well documented that drip irrigation is perhaps one of the worst systems devised as far as the food web goes. Don't be fooled into thinking you never have to do any water changes in an Aquaponic system. This is not so. If you do not do any water changes in the system you will get a build up salt that will in time cause the wipe out syndrome. This when one day your system looks to be ok the next day the system starts to die. One of the best ways to keep track of your systems salt content is plant some beans. Some of the beans don't like salt and will start to go black. Of cause the best way to see for your self the salt level is buy a salt water BRIX Meter (a.k.a. Refractometer) not very expensive about $60.00. Very inexpensive if it warns you of pending doom. Every one will say wow to much of a cost. Hmmm not if it saves you hundreds of dollars in fish and plants.

Anyhow sorry to waffle on so long. Take Care All. Regards, Barry.
Oakhurst Aquaponics said:

The kit includes everything necessary to build the system in our video, excluding some standard tools.

Rupert, thanks for your input but it is a bit presumptuous to make such harsh criticisms of our system based on a few simplified drawings.  Obviously some details have been left out.

We are confident that drip irrigation alone provides enough water savings to make economic sense in the vast majority of areas.  Our system has been tested in drought conditions, and losses were minimal.  In those areas that must contend with poorly-considered government restrictions as well as drought, grow beds and water recycling can be added, as mentioned.  But restrictions generally aim to prevent evaporation losses from sprinklers, which can be quite high.  Our drip hoses do not have this issue.

Our system is obviously not for everyone.  It is aimed at users in the temperate zone, and who have a relatively reliable water supply.  But it is modular, and flexible enough to be expanded for use anywhere.

[RupertofOZ]

barry hocking said:

Of cause the best way to see for your self the salt level is buy a salt water BRIX Meter (a.k.a. Refractometer) not very expensive about $60.00. Very inexpensive if it warns you of pending doom.

 

A Brix meter... while a refractometer... measures sugars... not salt...

 

By definition ..... One degree Brix is 1 gram of sucrose in 100 grams of solution

 

Buy an ATC (auto temperature calibration) Salinity Refractometer...

[barry hocking]

Ok lets take out the word brix and just add Refractometer meter.  The company I bought mine from added them to the brix meters as they both work on the same system of refracting light. (Oh yes it was a company in the USA.) They also measure alcohol, anti freeze, oils and lots of other chemicals. Barry.  Is that more politically correct for you?

[RupertofOZ]

Too true Barry... they're all (mostly) refractometers... that all work via refracted light... and all have a relationship to specific gravity of a substance...

 

But the scales are almost impossible to relate to one another.... even relating specific gravity (of salinity)... to salinity as measured in ppt.... is almost impossible... without a chart and a calculator... (although most salinity refractometers have both scales incorporated)...

[barry hocking]

They sure do and when my readings get a little on the high side I do a 10 to 15% water change. If I do not do a partial then all will start to suffer both fish and plants. When water evaporates it leaves salt and a lot of other nasty's  behind. Regards, Barry.

[RupertofOZ]

When you say "salt" Barry... exactly what do you mean????

 

"Salts"... in a hydroponics sense... are typically chemical compounds that have/are precipitating out....

 

But generally, in aquaponics... there shouldn't be any "salts" being input.. or output... unless you're actually adding salt... NaCl...

[barry hocking]

Sodium Na Latin: natrium It's atomic No. is 11. Also another problem with not doing any water changes is the build up of fluoride. Fluoride can not be filtered out (except with a reverse osmosis filter) that I know of. When water evaporates only water evaporates nothing else. If you add water from a Town water supply or river system then you are adding salt and other chemicals that can't be removed without a partial water change. No if's no but's you are adding salt. End of story. Regards, Barry. :-)

P.S. Fluoride is a very bad element that causes more problems than it cures. We need it as much as we need GMO's.

[Jon Parr]

I'm confused, Barry. I'm pretty sure Rupe knows what sodium is, and I had the same question as he did as to your meaning of "salt", and you didn't answer that. Do you mean sodium, or all salts, being a problem in aquaponics?

I have to question your opinion that salts accumulate to toxic levels as a matter of fact. You didn't factor in plants and fish using them up. If you were to try to grow plants in RO water, you would find that plants need "salts" to even survive. Hydroponic nutes are simply salts measured out in quantities that plants need. Some hydro growers use a fresh batch every couple of weeks to avoid an accumulation of salts not used by plants, but others monitor what's missing and add specific nutrient salts to the same reused solution for much longer. If a hydro grower were to stop adding nutes, and only top with water, then salt deficiency would be the long term problem, not toxic salt accumulation.

I was under the impression that AP does not need water changes as a rule, especially once stable and growing a wide variety of plants in various stages of veg and flower. I have well water, and have not changed water in my AP in the two years it has been operating, only topped up. Am I just lucky, or have others had similar results? Thanks for making me think about it Barry.

In nature, I suppose the partial water change idea fits. Every time it rains it leaches salts from the ground, no doubt helping keep salt imbalances in check. And those salts end up in the ocean, hence the saltiness.

As to fluoride, I'm no expert, but isn't fluorine a gas like chlorine, and eventually off-gases from water? I know it sticks around longer than chlorine, and that it why it is commonly used to dissinfect hot tubs where chlorine disappears too quickly. I've read of controversy in flouridating drinking water, but never heard of crop or fish problems where flouride is naturally high.

[barry hocking]

OK you guys must be the experts and I know nothing. I will keep my mouth closed from now on and stay out of any further discussions. Barry.

Jon Parr said:

I'm confused, Barry. I'm pretty sure Rupe knows what sodium is, and I had the same question as he did as to your meaning of "salt", and you didn't answer that. Do you mean sodium, or all salts, being a problem in aquaponics?

I have to question your opinion that salts accumulate to toxic levels as a matter of fact. You didn't factor in plants and fish using them up. If you were to try to grow plants in RO water, you would find that plants need "salts" to even survive. Hydroponic nutes are simply salts measured out in quantities that plants need. Some hydro growers use a fresh batch every couple of weeks to avoid an accumulation of salts not used by plants, but others monitor what's missing and add specific nutrient salts to the same reused solution for much longer. If a hydro grower were to stop adding nutes, and only top with water, then salt deficiency would be the long term problem, not toxic salt accumulation.

I was under the impression that AP does not need water changes as a rule, especially once stable and growing a wide variety of plants in various stages of veg and flower. I have well water, and have not changed water in my AP in the two years it has been operating, only topped up. Am I just lucky, or have others had similar results? Thanks for making me think about it Barry.

In nature, I suppose the partial water change idea fits. Every time it rains it leaches salts from the ground, no doubt helping keep salt imbalances in check. And those salts end up in the ocean, hence the saltiness.

As to fluoride, I'm no expert, but isn't fluorine a gas like chlorine, and eventually off-gases from water? I know it sticks around longer than chlorine, and that it why it is commonly used to dissinfect hot tubs where chlorine disappears too quickly. I've read of controversy in flouridating drinking water, but never heard of crop or fish problems where flouride is naturally high.

[RupertofOZ]

Sodium is certainly an element that can cause concern if it were to accumulate... but salt (NaCl) is only usually added into aquaponics systems to address nitrite issues during cycling... or for disease treatments....

 

Both are usually only for short periods of time... and diluted with regular water top ups, or even (some) water exchanges...

 

Some, of any salt added for the above reasons... is taken up by plants... especially, from my experience... by tomatos, that suck water in like a sponge, and through it back out again.... and celery...

 

Most plants can handle short periods of 6ppt salinity... but strawberries, cucumbers and a few other things... wont tolerate salt beyond 2-3ppt...

[Chip Pilkington]

I add 200L a week just for top up water in my larger system (about a 2000L system). So basically, I turn my water completely over about every 2 1/2 months. That's what, 10% a week?

My wife also swipes a fair amount every week to water her flowers.

Though I'd never do a water change as in the "Aquarium" sense...guess I should qualify that - outside of lowering salinity due to a treatment of sick fish, I'd never drain and fill for the sake of changing out water. But then, I believe the standard AP system gets a fair blast of fresh water just through top ups (and replacing the water your wife steals to water her orchids!).