Backyard Aquaponics
A place to discuss aquaponics

An update:

Measured the amount of pellets that fish have been fed this week. 1kg over 7 days (about 140gms per day). That is by just feeding once per day - except on the weekend when I tend to feed a couple of times. This weight does not include the mealworms, African Black Beetle larvae or green stuff.

The ammonia and nitrate are both 0 (though this is 24 hours after last feed, and the ph is now stable at 7.2. The dkH is 5. Nitrate is very high (between 80 and 160, but fish and plants are happy and it does not seem to be getting higher, so all is good. I suspect at this high level I will definitelly be loosing some to the atmosphere (water has a smell to it - not unpleasant though).

I have been feeding the fish well for the last few weeks and they are clearly growing. Am tempted to try and net one of the biggest ones to see what it weights - my estimation of 300gms which I have been giving may be an understatement.

how many fish again vb?

dunno about the nitrate loss to the atmo as its a dissolved solid, not dissolved gas

ammonia maybe at high ppms.

You might be thinking of anerobic nitrification where the nitrates is reduced back to N2 gas by another bac.

okay - maybe the plants are keeping it under control then - though looking again at the nitrate test just now, it is very dark, so I think nitrate is actually creeping up. Will continue to monitor. Taking one for the team remember. What is the first sign that nitrate is higher than fish are handling. Will they stop feeding or will they just lose condition. They look very healthy at the moment.

if ound that my silvers just wouldn't eat any more.........I guess thata pretty good bio-feed back! no eat = no more nitrates produced! LOL

Righto.

Steve - 30 perch - about 15 each of silver and jade. And there is that mongrel fish in there 2 - sooty grunter I think.

Five of the silvers are really small and will probably always be. They are the first ones I had and were bought from an aquarium shop - sold as feeders. Poor buggers were in terrible conditions at the shop and have been damaged for life. I will keep them though until they either get big enough to eat or die.

Most of the other fish ie 25 - are a fair size.

so on 25 fish that works out to be about 75grams weight gain per fish at worst case scenario of 2:1 FCR. Not bad

Glad you've had luck with the CaCO3, its the go for AP IMHO

Yep - trying to tell people about that at every opportunity. Will sometimes fall on deaf ears - but hopefully not always.

Sounds great VB. LOL on the smell. I have just set my seedlings in rockwool cubes that were soaked in fish emulsion and seaweed concentrate. Love the organic fertilizer, but it smells like a fish died in the corner and my shop, which is an attached building, smells the same.

Someday, I will get accustom to it and wonder way my visitors are retching

- I don't really even notice the slight smell of the fish tank, but my wife reckons it stinks.

It is certainly not a bad smell though - just like a normal aquarium.

our tank smells like a clean creek we like it

Yep, love the smell of the fish tanks

so what is the consensus of opinion
CACO3 powder or shellgrit form????

I personally think that the shell-grit breaks down to a degree and then stops being effective. The powder provides immediate effect and I expect you get full benefit of it over time as it continues to dissolve. I will put some more in my system soon to raise the KH from 5 to 10 dKH and then monitor it from there.

I will put some more in my system soon to raise the KH from 5 to 10 dKH and then monitor it from there.

VB, i got a feeling that its not going to have the KH effect you want. Unlike bi-carb its only slightly soluble, so in my mind once that saturation point is reached thats all the dKH you'll get (do you prefer using german degrees? i'm a ppm man )

Do me a test if you can. get a glass of tank water and then put a table spoon of carbonate in it, give it a good old shake around and leave it in a dark place for a few days, then measure the KH....

or have i confused the shit out of the situation?