Backyard Aquaponics
A place to discuss aquaponics

Does excess nitrate cause slow plant growth ? It says so here http://www.highnutrients.com/nutrient-deficiencies.html

Why I am asking this - My system story: I don't have a test kit, so my only (horrible) way to solve problems is by patience and trying every possible cause, safely. When my plants slowed their growth, I usually tried to feed more assuming low nitrates (ph is guessed to be fine as I have an egg shell buffer and the fish aren't looking bad or dying and I don't use high ph stuff like limestone.)
So I feed more. No result in plant growth. But when I went out of town there was a burst of growth.

So now I am guessing I have horribly high nitrates, and not low nitrates. This is possible because it is a small system and the 50L water can easily become 'oversaturated' with nitrates aver a month of feeding especially when the plants also don't grow fast and suck up nitrates.

What are your experiences ? Does anybody have high nitrates? Janet had 1000ppm in her old system I heard... what was the plant growth like?

Gokul I think you're going to have to test your water to find out what's going on and get a baseline. There are just too many variables to guess.

The was recent discussion regarding Nitrate toxicity in another thread... but I think that related to human consumption....

Don't believe your problems are "nitrate" related Gokul.... IMHO, the plants will either take up what's available... or what's required....

Think your problems may lie elsewhere.... need some test, baseline data as Jazz says...

Nitrogen can be locked out in hydro by pH and temperatures, mainly the latter.... also tends to lock out Potassium as well..... bad for plants...

I think Janet also found that when she corrected a pH problem, her high nitrate as well as a some other problems went away.

How much is some egg shells? And How are they being implemented into the system?

When I first started, a fish guy assured me that I would not need buffering with the well water we have around here, he was wrong. In my first system with only river rock and sand, the pH did drop once cycled even through my source water has a pH of 8. A few cup fulls of egg shells was not enough to bring it back up.

If pH truly is ok then high nitrates should be causing overly lush green leafy growth on most plants and a lack of flowering while plants that are light feeders would be showing signs of fertilizer burn.

With nutrients, if they are out of balance, it can cause all sorts of strange looking things with the plants. It seems that in Aquaponics the usual lacking elements are Iron and potassium. A lack or pH lockout of Iron often looks like the new leaves of the plants are fading while the veins stay green. Potassium def can show up as dieing patches on the leaves (spots) poorly developing fruit, powdery mildew and weak root growth. Lack of phosphorus while having too much nitrate may result in the plant not flowering.

A test kit would really help diagnose things. Then again, plants often go through a phase just after they put out their first true leaves where they seem to stall while they work on root growth before they take off again in the above ground growth. I have noticed this to happen for around 3 weeks it seems.

Oh!

Hmm...


I have very little egg shells... at first under pump outlet (on GB), now buried under surface (when I added another GB two weeks ago).

I'll try to find out about test kits... I simply can't seem to find any around here! Seems to be uncommon in south india...
I'll try harder to find out where they exist.

Here in OZ we get ours online from .... http://www.theaquariumshop.com.au/shope ... r+Test+Kit

Or from Joel.... maybe cheaper for Joel to post you one over from Perth....

Or contact the Manufacturer - Aquarium Pharmaceuticals... http://www.aquariumpharm.com/ .... API Freshwater Master Test Kit ....

Any aquarium shops or online stores in your area Gokul

I expect you may have to buy online and have one shipped to you but hopefully you can find something that wouldn't be too costly from some where not too far away.

Other places you might be able to get stuff like a pH test kit from a place that sells educational supplies for chemistry classes. Or it might be possible to find some sort of test kit that could test for nitrates in drinking water supplies.

Good luck!

Since this is a tropical area, (plus lack of common knowledge about the nitrogen cycle) most people get by cycling without any test kit... there seems to be no demand for it, nor any supply in any local fish store.

I might be able to find a source of test kits if I search hard. Otherwise I can do an interesting job of finding out what reagents could be used and get them from chemical stores (which are quite common. Even schools have chemistry labs you know...)
For example, I could (relatively) easily test ph by buying reagents from a chemical store, since we did that at school. (Apart from reagents like methyl orange and whatever.., at the least I could use litmus paper for a really crude test - whether its acidic or basic )

You know how some of the aquaculture is done here? Not at all intensively... they just put fish in a large water body and dump manure so that algae and other organisms come about, which in turn feed fish. They don't even do any feeding... (And they work). So test kits may be hard to find.
(I heard there used to be a village tradition of leasing the dry pond land in summer to grow nice crops - elementary AP, though I personally don't accept it as AP actually)

TCLynx, I didn't see your post before mine.

Ah yes they do perform extensive ground water testing and I have seen online pdf files of data for nitrate, ph, all kinds of hardness, heavy metals, bacteria(coliform) count, etc for my city.(It's available online, need to google it.)

Another likely cause is the build up of conductivity... the water evaporates quite a bit, especially with the bare new growbed (which I covered recently with a jute sack) and I keep topping up... in a small system salts can accumulate fast if you do too much topping too fast.

Ah the feeling of sillyness that you have when you simply guess one thing after another with no concrete testing devices...
I'm really going to arrange for testing-equipment-and-stuff when I have holidays a week later. Will solve a lot af my problems.

Gokul... dont go trying to attribute too much hydroponic techniques or terminologies to AP.... a lot of them just don't transfer across... different processes and fundamentally different nutrient delivery and constituants...

In hydro.... yes conductivity will measure "salt" buildups..... as the pure "chemical" components of the nutrient mix precipitate out with pH and temperature....

The nutrient mix is a combo of "soluble" chemical compounds... either premixed... or in a "powdered" form that's mixed accordingly.....

IMHO.... the nutrient solution of an AP system is totally soluble in terms of the necessary nitrates.... and wont "precipitate" out... well under normal conditions anyway... and any compounds that might tend to (i.e. Calcium Carbonate) are self regulating (via pH/buffering).. to the point that it just doesn't occur.....

And the system is continually "refreshed" so to speak.... and vastly greater volumes than most hydro nutrient bins....

I never started out from the hydroponics side though...
Started on the fish side.
I started out by the desire to maintain my own (sparsely planted) aquarium as an ecosystem (not neccessarily as decorative eye candy).
I was drawn to AP by the no-maintance (water change) nature, super filtration for fish and of AP being the grand daddy of all mini-personal-hobby-ecosystems.
And now I want my next AP system to supply all (ok most of) my plant food needs (I am a lacto-vegetarian so no fish eating for me)

Found this Meet an aquarist series: The aquarists of Bangalore There are four parts.
I also found a local yahoo group A-s-k · Aquarists of India. Still finding out about local test kits sources.
Also this Some Photographic Impressions of Aquarium Stores in South India for you.