Backyard Aquaponics
A place to discuss aquaponics

Yeh hurts looking at his eyes doesnt it, pretty sure he was blind this morning becuase I could net him no problems, put him into a airated bin with 20 litres of the original water and was able to put my hand in the water and pretty much touch him without him even flinching, I used the ponds nitrited water to settle him in and salted it up and then over the last couple of hours Ive been increasing the fresh water content to the point now hes in 160 litres of water, the nitrite readings now in his little stand alone tank are just under 1, so the nitrite readings in my main tanks must be well over 5, only my card colours read to 5, for info this fella even though his eyes look bad I think he can now start to see again becuase when I put my hand near the surface he kind of rolls over a bit to get a better look at the shadow

Also becuase of the amount of water required to bring his nitrites down I decided to carry out a 50 percent water change on the main tanks as well and will retest tonight

Edit:: changed all the nitrate statements to nitrite, its nitrite thats the problem, thank god Im still on holidays

Whats really dissapointing this year, been doing hydroponics for a long long time and always have massive bumper crops at this time of the year, but now my plants are almost all gone, all seedlings are pretty well dead and those that have been transplanted recently have stunted and started dropping there leaves

Im assuming becuase Ive never seen this problem before its nitrite poisoning of my plants

Absolutley decimated crops, theres like one plant alive amongst each container, usually you would be lucky to see the fence

Simso, I don't think it is the nitrite levels that he is suffering but the ammonia levels... the nitrite causes brown blood disease, which prevents oxygen from being transferred in the fishes blood... if he was suffering from nitrite poisoning, he would be somewhat gasping for air and apparently they can get better almost instantly when salt is added... but you have salted to 2.5ppt hence it mitigate against nitrite poisoning...

It is the ammonia that you should be measuring to reduce... not the nitrite...

As F&F said, and as you should know from hydroponics - pH 7.9 - 8.0 ain't great. Was there a large change in temperatures? Some have suggested that there is actually different strains of the same bacteria that operate at different temperatures. Did you top up from the tap? Chlorine kills bacteria.

Increasing turnover and biofiltration is the right track, you might just need to ride this one out.

Also, ammonia is more poisionous at higher pH levels (below 7 it forms Ammonium which is less poisonous still). Fix the pH slowly and watch it to see if it bounces back up. Fixing pH will make Ammonia less poisonous and help plant nutrient uptake.

yes gem and we have had warm temps as well that increases affects of Ammonia, shell grit to bring down PH, amm at 1 with the temps and pH would be severe, man I wish I could find that chart, rupe has it saved so post it rupe

Ok Simso... not sure why your ammonia and nitrite have spiked so markedly... especially if you've added extra filtration...

But obviously, there's something amiss causing the ammonia spike... ie. over feeding, dead fish... or under pumping/filtration...

Without going back over your thread... as to how you're draining your growbeds... overflow standpipe or bell siphon??

Regardless... I don't understand the rationale for limiting your flood to a few (3-5) minutes... standard BYAP kits utilise a 15/45 cycle... and a bell siphon should/normally is run continuously...

I'd suggest that....

You do a 50% water change immediately... just to bring parameters back to within a controllable level...

Stop and continue to cease all feeding...

Siphon/vacuum all/any dead fish or other matter from your fish tanks...

Increase your flood times to 15/45.... although continuous pumping for a day might help...

Add extra aeration...

Here's the ammonia toxicity chart (again)...


As you can see... at your pH and water temp.... you are beyond your ammonia toxicity limits...

You also have extremely high nitrite levels... and probably depleted oxygen levels...

Your fish are "burning" to death.... water change immediately... will lower nitrite and ammonia levels... drop water temp and pH ....

Lets say a water change brings your pH back to 7.4... and temp back to 24... then your ammonia limit would be 1.5.... as opposed to the current 0.5 (approx).... and your nitrites back to maybe 1 or 2...

And probably elevated your DO by 50%...

If I was a fish... I know where I'd rather be...

A water change will bring your salinity back by about 50%.... no problems as far as nitrites go.... but I'd probably bump it back to at least 2-3ppt in the next day or two... just to soothe the fish...

Will test again tonight,

Using standpipes in all grow beds.

Have carried out a 50 percent water change today already = 1000Litres of fresh clean bore water, have dumped a kilo of salt in as well

Water is crystal and I mean crystal clean, no food waste or plant waste in the tanks

The pump run time was all about minimum energy consumption to achieve required gains, as there is no real consensus what the mimmum flood time is I have my pump running enough to flood all grow beds and continue for an additional minute after flooding every hour. I know a lot of people use a 15/45 cycle but this is based as openely admitted by the mechanical limitations of the timers most people use.

Hydroponics for me has always been enough water and food to moisten roots and then as much aeration as possible without allowing roots to dry before recomencement of water again

The problem Im having might be as simple as the bacteria need a minimum amount of flood time as well to populate, this is unknown and a massive learning curve. The problem still arises as to why all plants are stunted and dying off. I know what ph lockout is and this is not it, almost like a toxin in the water that Im not used to dealing with, hence why I thought it might be nitrite poisoning thats killing stunting my plants

As I said crystal clean. I also have an air pump running for each fish tank

While there might be a minimum flood time required for the plants... there also a question of tank volume turnover... both for oxygenation...(both fish, plants and bacteria)... and filtration...

Hydroponic systems such as intermitant drip irrigation or "ebb & flow" can be successful... however IMO... a constant flow NFT style of hyroponics is the simplest and most productive....

Definitely not a fan of intermitant pumping hydro style...

Your plants are definitely not being "nitrite" poisoned... more likely... with the interuptions... they're just not getting sufficent exposure/uptake of nitrates... and with your pH, perhaps even some trace element lock out...


Even continuous flow would probably be better... ala C1... but 15/45 should help ... IMO

I also agree, but to get 15/45 the pump at 455lpm is to high everything would overflow, my 12000lph pump draws 150wts of power which at an hour on hour off = less than $20 per month to run

Like I said big learning curve, even wouldnt be surprised it has alot to do with as you mention rupe, the fact that the water is not around the roots long enough to provide sufficeint nutrient uptake, in about an hour will redo all my tests again

Re my pump, yes everything starts to overflow big time after a few minutes. But I need the pressure to operate all the ball valves, Ideally the best setup is looking like a pump running continuosly with a valve oscillating between a few grow beds at a time, ps my pump is 1600watts

At what Ph level does the nutrient lockout begin.

Is there some sort of scale or is it once the PH gets to 7.7 for example the nutrient is
locked out.

as you can see by the chart simso as well at water temp 24 ph 7.9 ammonia is toxic at .5 you at 1.5 is way way to high, 3 times the legal limit, your busted

yeh but what is stunting the plant growth and killing the seedlings

Heres a photo of a surviving capsicum plant see how the leaves have dropped off and left nubs, theres an oregano seedling on the front left which I planted 2 weeks ago, its pretty well dead now, and down the back on the left is a watermelon seedling which I relocated yesteday (still looks okay)