Wow, are these trout growing fast! It seems like they get bigger every time we look at them. Most of the fry are in the 3-5 cm range, with a few lunkers to boot. They are starting to lose their parr marks and the pectoral fins have developed the classic orange and white identification stripe. The estimated population has remained steady at 270 trout. The trout seem very happy. The Nitrate levels have gone way up to 80 PPM. The Nitrate test kit has always seemed unreliable, as the dark red colors on the match card are tough to read when comparing to the results in the test tube. As we discussed in our last update, we decided to confirm the chemistry readings by purchasing a few Water Analysis kits from Chemetrics. These test kits involve obtaining a sample and then breaking a vacuum-sealed glass ampoule (that contains the testing chemicals) with a capillary tip that sucks in the proper sample and subsequently changes color to indicate the content being tested. We purchased a variety of these kits over the last two years, and they are easy to use to obtain accurate results. You can learn more about Chemetrics test kits at their website (www.chemetrics.com). The test that we were most interested in is Nitrate, as we want to confirm what we thought were lethal Nitrate levels. The Nitrate test kit we use measures nitrogen amounts between 0.0 and 3.0 PPM. To convert this amount to Nitrogen as Nitrate, we multiply the results by 4.4, so the highest PPM that we can detect is 13.2 PPM. To test the trout water we use a 5X dilution where we mix 4mL of Trout Tank water with 16 mL of distilled water. Then we pour out 15 mL into the reaction tube and follow the directions in the kit. With this dilution method we have confirmed that when the aquarium Nitrate is reading 80 PPM, the Chemetrics test kit measures the Nitrate content at 38.5 PPM. This is comforting to know, but it still means that we should look for ways to decrease our Nitrate levels. We are changing 15-20 gallons of water a week, but we would like to try adding watercress to see if we can lower the Nitrate levels naturally. In any case, the trout still seem happy, so we are not too worried.
The Ammonia levels have increased to 0.25 PPM, but the Nitrite levels have remained at 0.00 PPM. This indicates that the Nitrosomonas bacteria and the Nitrobacters bacteria are doing their jobs. The Hydro sponge seems to have really helped boost the size and effectiveness of the bacterial populations. We have not had any issues with white mold on food or surfaces, but we have seen a few thin brown mold spots develop lately. These seem to “wipe” off so I guess that we just keep scrubbing.
We are a bit concerned about next week as we are on vacation and there is no one available to check on the trout. The good news is that we can all keep an “eye” on them with the web cam, so this gives us some comfort. You can see the trout too at our website: http://montgomeryschooltrout.wikispaces.com/. We are working on plans now for our release next month. We will likely let most of them go in late April, and hold on to 10-20 until the end of May just to see how they do with less fry in the tank.
We hope that all of your tanks are doing well, and that you are enjoying the spring weather. In the meantime, just keep swimming!
The Montgomery School Trout Team!
