Backyard Aquaponics
A place to discuss aquaponics

Just keep in mind that while ammonia is more toxic at high pH, nitrite is more toxic at lower pH. Adding salt helps but nitrite is very dangerous at lower pH's

Thanks Don. They are out of that situation now, so hopefully all will be good. I normally aim for 0 nitrite of course.

Went out to feed the Barra tonight. Have to turn the light on and let them wake up a bit before feeding can start.

While waiting, I sat and looked at the fish for a while. They are in the round poly fingerling tank now, so not as easy to view as when in the aquarium. Need to watch from above.

One thing that is fairly obvious is that there are a few fish that are really quite large compared to the others. The fear of course is that these are eating the smaller fish - which is speeding up their growth even more. I won't have the chance to even consider getting these larger fish out and by themselves until the weekend, at which time I can harvest the perch that are in the other side of the nursery (in second fingerling tank attached to the first) and try (try being the operative word) to catch the biggest barra to move them.

In the meantime - all I can do is try and keep them fed and hope that the losses are minimised :-/

Dam barra and their penchant for barra lol.
Of course the biggest problem is the biggest barra somehow manage to hide the best too!
Was thinking before about nitrite and thought I'd mention a technique I have used before but don't understand on a level to be able to explain... but anyway when our water comes out the tap full of nitrite, I can 'age' in a water container (using plastic garbage bins atm) for a day or 2. Anyway when it comes thru the taps with lots of nitrite you can add chlorine to oxidize the nitrite then add dechlorinator and boom no more detchable nitrite.
No help really for water that is already in a system but wondering if ya couldn't divert water to a holding container, oxidise nitrite, detox chlorine and then re-add it too the system. Sounds like a hell of a nightmare but who knows there may be a situation it's suitable for and maybe someone can explain how it works. Will have a quick research as the murkey 'facts' I know about it were told to me years ago by a crazy catfish breeder lol

VB, would you consider clove-oiling them to grade them?

It's a step up from the zap stun gun I almost reccomended.
OK so I wouldn't seriously suggest but damned if it doesn't work well on carp

Don - I didn't realise that tap water had nitrite in it - just chlorine or chloramine (which presumably results in ammonia when neutralised). Cna you tell me more.

Jaymie - would consider it, but don't have any. Also, have heard some nasty things about the safety of the stuff. I'll be better prepared next year and will have made some grading grids or something.

VB you would be supprised what the tap water has in it, i can get why people are so affaid of drinking recycled sewerage, it has to be treated much more than they treat the exisiting drinking water its actualy almost pure

also drinking pure water is not a good idea over the long term as it is "hungry" and strips minerals out of almost everthing it touches in fact H2o is one of the strongest most agressive solvents on the planet
OR at least os i was told

Ok so if you test your tapwater and pick up nitrite it's usually from bacteria in the pipes converting chloramine to nitrite. Well thats the theory I was told at some stage by someone. Usually happens with older pipes and only to people at the end of the line.
First step for me on water change day... test the tapwater. See if a partial water change will actually make the water better or worse.

delgrade is right, RO water will strip what little minerals you get out.

not that i agree with the shite they put in tap water

Thats why I always mix it 50/50 with straight tapwater when using in fish tanks. Actually thats half the truth as I use as topup water in me marines whenever they evaporate down a bit.... helps avoid algae blooms that tapwater nutrients can feed

A quick update:

Was away for a lot of last week - getting back Sunday. Left the fish in the hands of the missus, who hates feeding them, but must have done a reasonable job because they seem to have grown well during the 5 days.

Tank is getting quite grubby and must be getting high in nitrates also. Water change and clean-up will be in order for the weekend. Have no idea how many fish are left - but I expect that all the slow growers have now been victims of the larger ones. Size variation is still large - but there are no tiny ones anymore. All fish can now eat 4mm pellets - however the strange thing is that they go off the floating pellets after a bit, but still want more food in the form of sinking ones. This is a bit of a prob because the barra pellets I have are floaters.

poke the pellets down wiv a stick

Is that before or after using a bicycle pump to blow 'em up?

1 at a time - all couple of hundred that I feed each session. No fanks. If I wasn't concerned about them eating each other, I'd refuse to buckle to them. But at the moment I'm feeding them some sinking crumble once they go off the floating stuff each feed. Will run out of that soon - so may feed them a bit of the native stuff (kinda sinks after a bit). Is lower in protein - but will do the job as the supplement. Once I get them in a bigger tank - I'll make a feeding ring and will refuse to feed anything but the barra floating pellet. Gotta use the 25kg bag I bought. Although it is only 4mm - they'll be getting it till its gone.