Backyard Aquaponics
A place to discuss aquaponics

Hi all

I was just interested to see if anyone had graphed time vs ammonia, nitrite concentration. I just wanted to know about lag time after feeding until the ammonia and nitrite levels increase and then decrease back to normal levels. I just thought this could be useful information because if you know how long this cycle is you would then know when it is best to feed your fish.

Sorry if this has been answered somewhere else but i have had a good look and could not find anything.

I think the best time to feed fish is when they are hungry and are ready to eat - some have noticed that fish (barra in particular) don't feed around 10pm even if the normal feed has been missed.

Ammonia is converted when it gets to the GBs, the time taken to convert it would depend on the amount of bacteria available. Increase in ammonia seem to be recorded mainly when there has been a substantial change in the system setup (fish population increase, feed amount increase, decrease in GB and water quality changes)

Basically it is not a one shoe fits all scenario - same with cycling a new system...how many fish, how much volume, what size GB area, water temp, pH etc

Short answer - no! I don't think anyone has graphed the above...and if they had, it would not necessarily mean it is a template for all systems

short answer is that i've never seen an ammonia or nitrite reading regardless of when the readings are taken in relation to the feeding.

Its a continuous process, not a batch process.

Is an interesting question though. It is getting very cold here at night, which means I need to start thinking about taking the grow-beds off line at night time. This means I need to ensure enough biofiltration inside of the shed at night time to stop an unhealthy ammonia and/or nitrite spike.

My plan is to firstly change the feed times on my autofeeder so that the second (and last) feed of the day is earlier (3pm). Hopefully this will result in the poo that is inevitably pushed out of the fish by the new feed being in the tank and out into the grow-bed by about 7 or 8pm when I will (eventually) turn off the beds for the night. Of course the fish will continue to produce ammonia all night long, but the question is going to be how much and what sort of biofiltration will I need to keep on top of it until 7 or 9 in the morning when I have the beds come back on. Currently I only have a 20 litre clay ball biofilter in the shed hooked up to the tank - this will not be enough, so I'll probably build something at least 100 litres. Once this has been going for a bit, one night I'll test things, taking readings every couple of hours till I go to bed, and if all is not good - I'll switch the beds back on until I get things sorted. Otherwise I'll leave them off and test again in the morning before they come on line again.

I am currently graphing my progress tracking, feedings, ammonia,nitrite, ect, but my set up is currently different that all others here. I am not tracking temp, but I should be..

The problem is, the only way to track ammonia production is to not have any biofiltration - unless you try and rely on nitrate figures and track back from there (which would be very hit and miss due to degassing etc.

VB: could you do a small duckweed tray and have light switch on at night time for the growth, then use the duckweed as fertiliser for the growbeds or to feed some fish.