Share thisYou’ve made it through the first part. Your equipment is set up, the facility is approved, you have animals in the system, and they’re happy. Things are going great; in fact, they couldn’t be better! And then something happens.
Something changes. You don’t know why it changed, and you don’t know how to change it back. What do you do before the integrity of the system is compromised? This article answers five very common questions that arise in the operation of an aquatics lab.
My ammonia levels are too high. What should I do?
Ammonia is a waste byproduct of living things and it may cause problems for your animals. The commercial aquatic holding systems available today have filtration designed to control ammonia levels, but sometimes ammonia levels are high.
The first thing to do when ammonia levels are high is to remember that we are part of a scientific community. One must accurately assess the situation prior to making changes, and the first step towards doing that is taking a step back and looking at the water. Does it have a yellow tinge? Do the fish look OK? Do the tanks look reasonably clean? Have the filter pads been changed recently? Next, check the pH to make sure it is between 6.8 and 7.8, and then measure the nitrites and nitrates. These are important preliminary steps in finding the cause of an ammonia problem.
One of the most common causes of ammonia spikes is overfeeding. Overfeeding leads to excess food buildup in the tanks and filter pads. This can create a localized, high ammonia level in that particular tank. Additionally, this excess food can exceed the capacity of the biofilter, especially on older systems. Filter pads that have gross amounts of excess food and are overflowing, can also create high levels of ammonia. It’s important to remember that if the filter pad is not changed, the food and waste that it has captured will continue to break down and produce ammonia. Scheduled filter pad changes (optimally two to three hours after feeding) will remove this waste from the system, and the overall impact on the biofilter will be reduced, resulting in a lower overall ammonia level.
Another problem could be that the biological filter is not operating properly. On new systems, the filter must first be acclimated in order for the bacteria to function. This process occurs naturally over about six to eight weeks. An easy test to determine whether or not the biological filter is working is to test the levels of nitrites and nitrates. If ammonia levels are high (greater than 1.0ppm) and nitrates and nitrites are very low (less than 2.0ppm nitrites and less than 10 to 15ppm nitrates), the filter could either not be acclimated or needs to be re-acclimated. Additionally, if the pH is below 6.5, the nitrifying bacteria stop converting ammonia to non-toxic nitrate.
This leads to another common, related concern: fluctuations in the pH levels in the system water. Different species prefer different pH levels to be happy, and wide variations can seriously affect eating, breeding, and ultimately, survival of your animals. Monitoring these levels is an integral part of lab procedure, yet still the question often arises:
My pH readings are too low/high. What should I do?
pH is an important factor in both animal health and the operation of the biological filter. Fish prosper with a pH between 6.0 and 9.0. For breeding Zebrafish, most labs operate between a pH of 6.8 and 7.8, but good results have been obtained with a pH as high as 8.5. Often the biggest problem on a system level is that when the system is heavily loaded with fish, the CO2 produced will drive the pH down. Sodium bicarbonate can be dosed in to the water to maintain the desired level.