It has been a month since I started this project so over the weekend I decided to gather some "data" from my system. I still think that I don't need to use the test kits to check the water condition. I'm not sure about the cost of those kits but for now I would rely on my senses (see and smell...no I'm not going to taste anything... yet).
First, the fish. I got one dead tilapia on week 2, that is basically it. the remaining fish are extremely healthy, and eat normally. I feed them twice a day. The water is not smelly even if I put my nose really close to the water surface. I think that shows the ammonia level is very low in the water, a condition which we want to achieve in aquaponics.
The plants however is not doing very well. My kesum has yellowish young leaves on week three. This week I realized the young leaves has turned brown and some are dead. This is not good. I don't know what is wrong. My friend suggest the system is not fully mature yet, I think he is right. The fish apparently does not produce enough waste for the plant or the bacteria is not fully colonized the grow bed yet. So there is not enough nitrates for the plant to grow healthily. My pak choy on the other hand...well...only one left. My fault! I have to admit I was too eager to move the pak choy sprout. I should have wait until they are about 2-3 inches high before I move them. I moved them too early (I want to arrange them in the bed) and all has dies except one. The One is showing food deficiency too.
I took a temperature reading on the grow bed. This is not the pebbles' temperature. The pebbles are pretty cold actually because the fish water helps cool it down. The fish water is very chilly! The temperature is ambient, probably the highest temperature for the day (note the time is almost 2pm). My watch also showing rain is coming, it rained cats and dogs at 3pm that day.
This is another modification I made to the pipe. I found that my water pump is too powerful, it can fill my grow bed in about a minute on minimum setting. So I drilled some tiny holes on the pipe near the pump end to release some water pressure and now it took almost 2 minutes to fill the bed. The flood and drain cycle now is about 2.5 minutes. I searched info on ideal cycle timing but I found no concrete evident of a good timing. Most people that use timer flood their bed at least 4 times a day for 15 minutes each. For automatic syphon like mine, most say they don't really care about the timing because frequent flood and drain actually introduce more oxygen for the roots. Also, I only use one pump with no bubbler in the fish tank. I have to keep my pump on 24/7 for the fish. This modification also introduce an underwater current in the tank. The fish like it, they keep swimming in and out of the current, good exercise! the current also helps feed the pump with waste as it moves along clockwise in the tank.
So, I put another month for the system to fully mature. By then the fish would grow bigger and produce more waste, hopefully the plants could get what they want.