Originally Posted by jaysee
I'm surprised that you chose fish food for your experiment. Ammonia would have been a better control. Sent from Petguide.com App
True, but I had fish food on hand and didn't feel like going looking for a pure ammonia source. I was curious about the food decomposition as well, I mention that below.
I haven't posted anything new as not much has changed.
So, still in process, day 31.
I did test the water 5 days ago and the ammonia was down to 0.5ppm from 1ppm on it's own. The issue is that I used fish food to bring the ammonia up and water changes to keep it at 1ppm or less. I only ever added food once and when I filtered it out using the coffee filter after the cycle was established, I could not get it "clean" so there were still minute particles decomposing which has been driving the ammonia production even since the filtration. If I had used pure ammonia I could have just stopped adding it.
I was curious to see how the food decomposed over time and saw that ammonia was present within 24 hours, 0.25 ppm, and in 4 days it reached 1ppm and required water changes to keep it at or below 1ppm thereafter... until I filtered the food out.
Today it is slightly lower, somewhat under 0.5ppm and the nitrates are between 0 and 5ppm, in the lower end of the range. I also did a sniff test, I stopped doing that pretty early on as the smell was pretty nasty. Today there is no bad odour, in fact there is really no discernable odour at all and I have a pretty sensitive sniffer. I won't be doing a taste test anytime soon, duckweed is one thing.
Once it is down to zero on it's own (all the food is decomposed) I will add another ammonia source to test it... it might still be fish food but it would be representative of what might be expected if there were some teenie tiny fish in there.
I could just dump it and refill with clean water and it would serve the same purpose but I wanted to see if the jar would still handle the overload that is in there now. I also wanted to leave it this way to see how much the nitrate concentration rises without water changes... although there may be no empirical measure (#ppm ammonia in = #ppm nitrate out) it will serve to demonstrate the system efficacy. Actually, I would like that measure as I think it is a 1:1 ratio but I don't know for certain. With no plants or fish I could measure this well enough... I may will look for some pure ammonia after all so I can do just that.