Backyard Aquaponics
A place to discuss aquaponics

Rupe didn't answer this directly, so I will:
Yeh, I think it's probably pH, OO has been calling it a "bacteria crash" or some such. Your bacteria don't like the low pH and die or become inactive. Not sure which.

If that's true, how come I have a non-zero nitrate reading? I took a nitrite reading this morning - zero.

I'm pretty sure my system has had low PH for a while, so given the sensible nitrate reading, the nitrosomonos bacteria must be working fine & they depend on the nitrobactus bacteria producing nitrite from ammonia. If either bacteria were dead or slacking off, I wouldn't expect to get a non-zero nitrate reading. Does that sound sane?

Not saying you're wrong Gemmell, just trying to understand what's happening in my system.

Water quality measurements for this morning:
nitrite = zero
PH = 6.4 (yay! on the up! I put in some bicarb last night & then a little more just now)
ammonia = 0.5 - 1.0 (hmmmmm)

Ammonia is still high.

Don't think you bacteria was "dead"... but it might have been "inhibited"... hence the ammonia reading....

And/or you've got a dead fish or two on the bottom...

Hiya Rupe,


Hmmmm, possible. It's difficult for me to see inside my tank cos the water has so much tannin. Which leads me to a question I've been meaning to ask for a while ...

Is there any way to clear up my heavily-tannined water? Mussels?

Scottie.

What is the alkalinity of your system in regards to pH buffer capacity.

If you have high algae/ bacterial or organic (tannins!) loading in the water it competes for oxygen in water as well as fish and nitro spp biofiltration bacteria.

in the Nitrificiation and Denitrification process of your biological filtration, one of the major by-products is Nitric Acid. The more acid produced the lower the pH. Shell grit as a solid matrix and bicarb soda as soluble.

Therefore boost your system buffering so your pH won't jump all over the place.

In respect to the Tannins, it is a fine organic particle that colours the water. Can you filter your water inlet with fine filter wool or sock (1.0 micron) without restricting flow? By the way what is your water source?

Cheers

Hi SH,


I'm not sure I understand the question, so if the following seems like a non-sequiteur you'll know why. I usually have some shell grit in the system so the PH hovers around 7.4, but I removed the grit a few months back - silly me!


Hey cool! I might try that. I suspect that such a fine filter will limit the flow, but you gotta try, right?


Rainwater. I have a diverter on one of my downpipes.

Actually Scottie, unless you're rainwater is getting stained by "tannins"... then the rich tea colour is probably due more to the bio-film that builds up in a mature system...

Wouldn't wory about if that's the case...

If your source is rainwater, where are the tannins coming from? dirty gutters, dirty roof or dirty water tank etc?

Good chance tannins will also end up making your fish not the greatest flavour to eat. Common off-tasting compunds MIB and Geosmin are compounds that are in tannins, algae etc and get locked up in the fish under the skin in their fatty tissue layer (between skin and flesh). if you have taste issues, always fillet and remove skin for eating, if not raise salinity of system prior fish harvest and cease feeding to "purge" fish.

Alkalinity is the measurement of the water buffering capacity. ie, the resistance to pH change from acid or base addition. Alkalinity is a standard water quaility test and considering your using rainwater, it will have quite a low buffering capacity. Thus, addition of bicarb soda will be most simple solution. There are better additives considering plant growth, as excess sodium will leave you little plant crop choice.

Cheers

Hi SH,


Nothing dirty! My GBs are not sheltered so leaves fall in them. Then when it rains the tannin gets into my system.



Hmmmm, I did not know that. Extra incentive to try & reduce the tannin then.

Do you know the particle size of tannin? You say to use a 1 micron filter. Would a 5 micron filter work?

Scottie, I really doubt the colour is due to "tannins"... is it just a rich "tea" colour??

OH! Yup, looks like tea.

What's your theory Rupe?

Mature systems also get an overall high organic biomass, algae, bacteria, biofilm, nutrient etc. This can also be your tea colour..

Recirculating aquaculture systems can get it if they do not utilise fine solids removal. the very little fine solids stay suspended in the water coloumn and do not get an opportunity to settle out of the water coloumn.

I would still advise your 5 micron filter, will always help, just compost any residue you trap.

It will be a matter of taste at the ned of the day if you are happy with your tea water.

Do you have a filter on your system? I'm interested to find out how others do this. I've been thinking about it a bit, but I'm not sure how to handle the large flow rates I have.

ie. a fine filter will inhibit flow enormously, & I'm not sure how to workaround that.

Another fish kill this morning. Is anyone able to tell me why this fish died? I'm guessing ammonia.

Measurements this morning are:
nitrate=40
ammonia=0.5
PH=6.4

Also, a question about my beans - they have some sort of deficiency. Does anyone know what is wrong? See photo below.

With a sunken belly like that for some reason or another that fish starved to death

I've come to the conclusion that Silvers and trout don't mix too well Scottie....

The trout just hassle them to the feed.. and generally chase/harrass and bully them...

I've been pulling about one Silver a week out of the trout tank... all looking like that...

Had a feeling that might be the case and the reason your ammonia might be spiking due to a death or two...