Backyard Aquaponics
A place to discuss aquaponics

cool... is good!!

The old sheep dips contained arsenic which hangs around in the soil around the dip for ages. Not something you want to contaminate your AP system with.

Nova

ems, didn't someone post that urine contained ammonia in the bi-carbonate form mostly, then the rest as urea? ammonia testkits may not (not sure) register these components.

I agree Erik dont think ill be piddling around with drip feed. Basically the limiting factor seems to be buffering, the bacteria go at it that hard that the ph plummets into the 5's in a couple of days if your adding too much. For my 6-700 litre system its 2 cups 2 days apart then nothing for a week.To be fair ive only got 3 gigantic basil plants ,4PNG spinach, and a tomato plant with delusions of world domination. To my mind using black waste is getting into the too hard basket, better to compost it.Besides 80% of the nutrient value of human waste is in the urine. One issue is as someone mentioned the salt build up, but water changes should sort that.

That's the problem with testing for something we can't see --we have to take the test kits word for it.... Any inherent inaccuracy of the testing procedure will skew the results.

Hi Steve,
The largest portion of the ammonia is in the form of ammonium bicarbonate, urea and urate make up a small percentage and decompose rapidly.
I don`t think test kits can tell the difference between types of ammonia, probably why they measure total ammonia? If you have 3 kits they`ll all give a different reading anyway lol so it`s all relative.

If a cupful of liquid gold added every few days does the job, it`s certainly a low maintenance system.

A drip feed arrangement would be more effort to set up but might be better for the bacteria, overall system stability and relatively constant nutrient levels, ...you`d still have to fill it every few days

I can imagine a seesaw type effect happening with the cupful method.
The bacteria might be on a downsizing trend due to lack of food just when the cupful arrives, so they`d have to repopulate to cope with the unexpected load?

Logically you`d get large spikes in nitrate concentration with a gradual decline to a minimum level, rather than a relatively constant level (fish populated system or a drip feed system) which constantly adds ammonia to the water with larger peaks at feeding times in the case of fish.

The O2 and alkalinity will be affected too, you could inadvertantly create low O2 and a large downward PH swing caused by the exponential increase in demand by the bacteria. It appears that approx 4.3mg of O2 and 8.64mg of alkalinity (HCO3) are needed to oxidise just 1mg of ammonia into nitrate.

A cupful every 2 days or a cupful dripped in steadily over 2 days.. might make a world of difference

another point may be is the bicarbonate form actually toxic to fish?

I know a commercial product for aquarium users ammo-lock binds the ammonia into another compund to detoxify it for fish (cheat ) but it will still register on the test.

might do a search on it...............

You actually got me interested enoguh to do a search on the net on urine....... by all counts it seems that it is pretty much sterile only containing hormones or metabolites of certain medications if you are onthem

Urine from a healthy person is quite sterile. It's the fecal contamination that worries me. Yes, yes, yes I know I seem either paranoid or germ-phobic. Remember: 1) female, 2) parent of two young children, 3) in daycare, and 4) married to an immuno-suppressed guy.

I heard from someone who heard ...

actually probably from my Dad, therefore source totally unknown ...

If you're stranded at sea, you'd be best to drink your shipmate's urine, not your own. Urine contains the waste from your own body, and it figures to me that your body might not want those same wastes best.

as I said, I heard ...

Lenny

Hi Janet,
In this day and age it probably pays to be paranoid and germ-phobic. Problem is the bugs are everywhere.

Steve,
Logically bicarbonate in itself shouldn`t be toxic.
Ammonium (NH4) is actually less toxic than ammonia (NH3) and the plants can use it directly, if they can beat out the competition for it.

The ph seems to be an important factor here too as above 7 the ammonium starts shedding the extra proton to become ammonia again.

It might pay to check the ph as well when testing for ammonia content.

Hex, yes, as the ph rises more and more NH3 exists as NH4 the equilibrium point shifts.

RE: germ phobic, just my personal opinion, but maybe that we are so germ phobic that they have such an effect. i'm sure more than ever before are our children sheltered from germs. For god sake, thats what our immune systems are for

JP, you're exempt from my rant, obviously.

Immune systems (most people) are built by exposure to germs/virii etc...

No germs... no immuno system....

Just ask the native populations of every country suddenly inundated with germy white [s]invaders[/s] settlers...

IMHO I think we might be doing our kids a disfavour with our cleanliness regimes...

Like I heard the best (maybe it was the only) way to obtain some of the beneficial bacteria in our stomach and intestinal systems was to eat dirt when we were kids....

well then, my kids have got REALLY good immune systems

mine too J.

started washing gravel at 1yo bugger, their too old to get them to do the system gravel requirements.

I contribute my daughters good imune system to the half cockroach I pulled out of her mouth when she a crawling baby
My son seemed to prefer sheep poo