The aquaponics system has been running for 12 days now and I have a few observations. I added four more goldfish to the tank today, bringing the total up to eight. Double the fish, double the poo! Yay! We get our fish from the feeder tank of the aquarium store, but they are really nice looking fish. They are Comets, which have larger fins than common goldfish, and they have lovely colours and patterns. They aren’t “fancy” goldfish, which is for the best, because they don’t have exaggerated body shapes or bulging eyes that could make them less hardy. The plan is to have 12 all together, which we should have in another week or so, providing the water conditions hold. I’ve been testing ammonia, nitrites and nitrates daily to see whether the nitrifying bacteria I wrote about a couple of posts ago have moved in. As of yesterday, there is no measurable ammonia in the water, so I am thinking that the filter media from Madeleine’s mature aquarium helped to speed up cycling the system. There is also no measurable nitrite or nitrate yet, though it is possible that the plants have sucked it all up. Speaking of plants, you’ll notice a couple of spiffy new fake plants in the fish tank. They provide a bit of shelter for the fish and jazz up the place.
I thought the basil leaves were looking somewhat yellow, so I added some more liquid seaweed to give the plants more nutrients. This gives the water a greenish tinge, but doesn’t appear to have any effect on the fish. At this early stage, everything is on the edge: the plants do not really have enough food because there aren’t many fish and they are small, but if there were more or bigger fish, the water quality would be dangerous for them. I just have to wait for the nitrifying bacteria to fully populate the system so that both the fish and plants are happy. By starting with small fish and small plants they can grow up together.
Most of the seeds I planted have germinated, though nothing has got as far as having true leaves yet. I had to pull the thyme plant I got from the grocery store. It didn’t look like it appreciated having a warm bath a few times an hour and I suppose not all plants do.
Some of the expanded clay balls have developed white hard water deposits on them. I don’t think I’ve seen that in any images of other aquaponics systems, but I can’t imagine it would be a rare thing. We have quite hard water in our well, and the ph is also high. Just as in soil gardening, the ph of the water affects how nutrients are absorbed by plants. Most plants would prefer a ph of just under 7, but ours is 8.3. I’m waiting to see what happens with it, because nitrification has a ph lowering effect on water. Most aquapons (people who do aquaponics) seem to have difficulty keeping their ph high enough. Now that the system appears to be cycled, I will be curious to see whether the ph drops. The high hardness does have a buffering effect on the ph, which means it may stay high for a while before I notice any difference.
For the next while I’ll be monitoring water conditions and plant growth in addition to fish and siphon watching. It’s all very addictive.