Troubleshooting your Vivarium/Fish Room
Troubleshooting your vivarium fish room
is a skill that comes with training from your supplier (if applicable), getting to know your system, and a basic understanding of aquatic animal husbandry and associated water chemistry.
The three main places I see troubleshooting:
1) Filters/System flows
2) pH adjustments/Nitrogen cycling
3) Conductivity/Salinity adjustments
Filters and System Flow
If you can see filter pads/sock/pleated filter readily, it’s easy to know when they’re clogged, in need of a rinse, or ready to change for a new one because you will be able to visualize debris. For filters that are in opaque flow chambers, however, it can be difficult to use sight to determine when filters need to be changed or cleaned. Here is when it’s important to understand your system’s pressure, when the pumps are “working too hard,” and what is its “normal” flow.
Systems like ours in the stock center—a multi-tank, flow-through system with one or two pumps—push the water through the filters, past sensors, and return to all racks in the system bringing water to tank where fish live. Decreased flow or water pressure is an indication that the filters need attention. Since the pumps are at the beginning of the line, any extra work from them can be an indication of a filter change need or a clog.
This is our grow-out tank system
This system has sixteen smaller, 9 liter tanks on one side and sixteen larger, 20 gallon tanks on the other. Two filter socks collect debris directly from the return from the tanks, then two pumps pull water from each sump below the larger tanks and push it past a 50 micron pleated filter. After UV filtration and passing our pH and conductivity sensor probes, it then flows back to either side of the room and return to the fish tanks.
What are the most common consequences for dirty or clogged filters?
-A clogged sock can cause a rise in sump levels which can lead to flooding; this changes the conductivity as well if you have an automated fill line of treated water for your system.
-Over-burdened pleated filter (dirty or clogged) can cause the pumps to run at higher-than-normal revolutions per minute (RPMs) to push water to the rest of the system. If this higher pressure is consistent work for the pump, this can be bad for the over-all health and longevity of the pump. (Being over-burdened also can turn it from effective mechanical filtration to less-helpful and unintentional biological filtration—more on biological filtration in the pH section.)
-If an individual tank drain pipe or overflow is clogged by debris, dirty filter sponge, or an escaped animal body, flooding in this tank can occur. Again, this can impact the conductivity or give an opportunity for other animals in the tank to escape if a proper lid is not in place. If certain parameters are required for an experiment, flooding events can negatively influence those parameters.
To identify your issue and guide you where to look first with systems and water flow issues, you need to know what the consistent, normal water levels are in the sump and tanks with normal working pump and filters. If your pumps are working harder over time, you can see if there was an isolated day or time for the escalation or whether it gradually elevated. If there was a sudden change in water or sump levels at a specific point, this could point to exactly when an issue occurred or could indicate that a specific maintenance practice worked or didn’t work—like if you have two different micron filters and someone used the incorrect size during a filter replacement. Gradual elevation indicates the gradual filling of a pleated filter or sock and, though choosing when to change said filter can seem arbitrary, there will be a point when it will be difficult for your pump to effectively push water through the dirty filter. Filter changes that work well need to be consistent but can be as basic as weekly or every other week for a filter change or alternate between a rinse and a change. You can also rely on filter pressure data to set a point on a pressure gauge to tell you “when this point is reached, change the filter.” Data points like this can also be something logged daily during animal and system checks in a physical or digital log to watch the change in pressure over time. For example, our system has an online data chart that keeps information visible for up to 90 days prior that we can look at trends and individual points on the graph.
pH Adjustment and the Nitrogen Cycle
Naturally in a cycled system, the bacteria on your bioballs, surfaces of the tank, and anything inside the tanks, such as enrichment or hides, manage the ammonia and nitrite from refuse and food debris but leave behind free H+ in the process. A cycled system refers to a closed tank system that has built up the amount of bacteria needed to manage the natural ammonia and nitrite additions that come from fish debris like excess food, their refuse, or dead animal decay—this is biological filtration. If kept unchecked, the pH would decline continually with the positive growth in bacteria. Stickleback come from a variety of water parameters across marine and freshwater habitats. Though marine water can have a normal pH as high as 8.3, freshwater is usually between 7.0 and 7.9. At the stock center, we keep our pH parameter set to 7.25.
Our system allows us to set up digital alarms when different water parameters are out of range. There are two dosing tanks attached to our sensors that will automatically and slowly add either a salt solution or sodium bicarbonate solution to the water to adjust the conductivity or pH respectively. For systems that aren’t monitored electronically, daily manual measurements with pH strips, probes, or kits can be used to monitor pH and free ammonia/nitrite/nitrate levels.
Aquatic Nitrogen Cycle graph
The cycling of the system is complete when there is little evidence of either ammonia or nitrite in the system. This can take 40+ days. It’s important to note that nitrate is removed with water changes since we do not have denitrification occurring in the lab and aquarium setting. When “feeding” or dosing a tank, it is important to have a consistent dosing day followed by a testing day to know how much is added and how quickly the ammonia is converted in the system. Graph sourced from link
While this graph has time as the x-axis, it does not give a temperature for this specific speed of growth.
Bioball images from Google Image Search
Bioballs come in lots of different shapes, sizes, and colors
Bioballs come in lots of different shapes, sizes, and colors
It is best to add your fish into a system or tank that is already cycled, but healthy stickleback can live in an uncycled tank if you have routine water changes daily or every other day as needed to help remove the harmful amounts of ammonia and, eventually, nitrite. Before you add fish, you can purchase aquarium bacteria solutions, a salt to feed and target bacteria growth (ammonium chloride), or use your fish food to help start a system’s good bacteria growth. If fish are already present, you can add commercially available additives to the system to help reduce the ammonia/nitrite levels.
When adding ammonium chloride or fish food, you will also need to have test kits for both ammonia and nitrite handy to check the level of these compounds found in the water. You can test the water once or twice a week for the first few weeks as you start feeding or dosing the system. The growth of bacteria is controlled by the water temperature (slower for colder and a faster for warmer temps) and is helped when the pH remains steady around 7.0-7.8. Higher than 8.3 is out of range for most marine environments, and since most of the bacteria we grow resemble where stickleback thrive—a nice, healthy brackish or low salinity water—, we view between 7.0-7.5 as optimal for our stock center systems.
Troubleshooting points:
-Ensure water changes are occurring through siphoning and cleaning the extra food, refuse, and debris off the bottom. Your tank system can have additional water changes through an automated percentage change each day by dumping water and replacing it with RO or other approved water sources.
-Clean socks or filters keep your system from being over-burdened with debris to help the bacteria manage the amount of ammonia and nitrite they have to work through. This is especially important with a newer system that isn’t completely cycled yet. Cycled systems will have a slight color on the bioballs which is the bacteria biofilm. Since most systems have bioballs in a relatively dark chamber or bag, the coloration is not due to algae growth.
Conductivity or Salinity Adjustments
As discussed previously in system flow, conductivity and salinity can change because of a variety of reasons due to issues with filtration—usually filters needing replacement, cleaning, or back-ups. (I will use conductivity exclusively from now on because our system uses conductivity as its parameter, but conductivity and salinity both gauge how much salt is in solution in the water in different ways.) In warmer (tropical) tanks, conductivity can slowly raise due to natural evaporation of the water leaving behind the salts. Since stickleback are cold water animals, we usually do not see a rise in conductivity due to evaporation. The changes in conductivity we see are due to water changes, RO refills, and malfunctions/miscommunication between either of these in replacing water into the system.
Water changes in the system can alter conductivity based on volume, frequency, and duration. If your system has a lower volume, a significant water change of 10-25% can easily change the conductivity. With flow-through systems like ours in the stock center, a 5 gallons removal is a large water change for our 300 gallon tank but insignificant to our 2000 gallon tank. You may choose to do a larger water change if you are managing ammonia and nitrite if you have the max recommended population of fish in an uncycled tank. Frequency and duration can have similar affects to large water changes, so you many need to adjust how frequently or how slow/fast your water changes are. If you refill your tank with premade water with a set conductivity, the conductivity may not change as dramatically.
Our system has a set water level in the sump that the system maintains. When we siphon out water or remove and refill a tank for cleaning, this lowers the water level in the sump and the float switch activates to turn on the RO refill. As the RO fills the sump, the conductivity changes as fresh water is added. As the conductivity drops with the freshwater addition and the parameter reading gets below the set point on our conductivity probe, the dosing pump will activate and add our salt solution directly to the tank. This continues until the probe reads the desired conductivity and shuts off the pump. Once mixing occurs in the tank, the system may continue to turn on and off until the desired conductivity is reached.
How can you troubleshoot conductivity issues?
-With a conductivity vat or refill vat with premade water at a set conductivity, it is easy to regulate the conductivity of the water getting added to the tank and system. However, if the conductivity vat is on an automatic refill cycle, the system will add non-salted water and dilute the water in the vat, lowering the conductivity. Since the system corrects conductivity in the flow system by pulling from the conductivity vat, if the water in the vat continues to dilute, the conductivity of the water in the entire system will drop gradually over time. The need to raise conductivity throughout the day occurs when we have our automated daily water changes turned on and broken into four to eight different dump and refill time points. Our system works best when we fill the conductivity vat, add salt to the amount specified by our supplier, and turn off the fill when the vat is full. That way, we know the salt solution remains high until we have to refill. Our animal care requires daily checking of the system, so whoever manages fish care each day looks at both our pH and conductivity vats daily to ensure they are full for when the system needs to adjust itself.
-If you are positive the conductivity vat is not diluting your system but your system’s conductivity is still dropping gradually, check the automatic RO refill in the sump. Float activation switches have the ability to adjust the angle of the float to raise or lower the resting water level of the sump. If the float switch angle is high enough or the tightening mechanism for this angle is loose, your RO water will continue to fill the sump. This will flood your sump, so check for an unusual amount of water on the floor in your fish room (fish care is notoriously wet with siphon hoses dripping, cleaning the fronts of tanks and taking a wet arm out of the water, nets for collecting fish dripping on the floor, etc.). In our system, the RO fill is faster than the conductivity vat and has resulted in a gradual change over time when malfunctioning.
Train your animal care staff to look for these changes and to note if and when an error occurs. In our systems, a buffer zone of about +/-20µS (microsiemens) is normal with our conductivity set point. Anything outside of that should be a flag to my student staff.