Rainwater Harvesting and Recirculation System for Greenhouses

Harvesting rain and groundwater for your greenhouse is environmentally friendly and efficient. Steps and considerations for harvesting rain and groundwater for our greenhouse:

1. French Drain System:

Source: Fine Gardening
  • Placement: Install the French drain system around the perimeter of the greenhouse to capture rainwater and prevent groundwater from entering.
  • Drainage Pipes: Use perforated pipes surrounded by gravel to allow water to flow into the pipes.

The optimal slope or angle for French drain collection pipes to ensure good water flow typically ranges between 1% and 2%. This slope allows water to move efficiently along the pipe without creating too much speed that could lead to erosion or an insufficient gradient that causes water to stagnate.

Here’s a brief explanation:

1% Slope: This is a gentler slope, suitable for areas with light to moderate rainfall. It ensures steady water flow but might require a longer drainage path.

2% Slope: This is a slightly steeper slope, allowing for effective drainage in areas with heavier rainfall. It provides quicker water movement but may be prone to erosion if not properly managed.

To calculate the necessary slope, divide the vertical drop (elevation change) by the horizontal distance. For example, if you have a 10-foot run and want a 1% slope, the drop would be 0.01 * 10 feet = 0.1 feet (or 1.2 inches).

Keep in mind that these are general guidelines, and the specific conditions of your site, soil type, and local rainfall patterns may influence the optimal slope for your French drain system. It’s crucial to ensure proper installation and backfilling with gravel to allow water to enter the perforated pipes effectively.


2. Collection Point:

  • Location: Choose a specific point where the drainage pipes converge and lead the water towards the greenhouse.
  • Beneath Foundation: Ensure the pipes enter the greenhouse beneath the shallow 12-inch foundation. Use proper waterproofing measures to prevent leaks.

3. Buried Cistern:

  • Material: Choose a durable, waterproof material for the cistern. Options include concrete, plastic, or fiberglass.
  • Size: Calculate the greenhouse roof’s runoff and the expected groundwater flow to determine the cistern size.
  • Filtration: Install filters to prevent debris from entering the cistern.

Calculating the size of the cistern needed for your rainwater harvesting system involves estimating the total volume of water you plan to capture and store. Here’s a general guideline to help you calculate the size of the cistern:

  1. Calculate Roof Area:
    • Determine the total catchment area of your greenhouse’s roof. Measure the length and width of the roof, and multiply these values to get the roof area in square feet or square meters.
  2. Calculate Rainfall Harvested:
    • Estimate the average annual rainfall for your location. This information is typically available from local weather stations. Convert this value to inches or millimeters.
  3. Calculate Rainwater Harvested:
    • Multiply the roof area by the average annual rainfall to get the total volume of rainwater harvested in cubic feet or cubic meters.
  4. Adjust for Efficiency:
    • Consider the efficiency of your rainwater harvesting system. Not all the rainfall will be captured and stored due to losses from evaporation, runoff, and system inefficiencies. A common efficiency factor is around 85-90%, so multiply the calculated rainwater harvested by this factor.
  5. Consider Water Usage Needs:
    • Determine your greenhouse’s water usage needs. This will depend on factors such as the type of plants, irrigation methods, and frequency of watering. Estimate the volume of water required over a certain period, such as a week or a month.
  6. Determine Cistern Size:
    • Compare the estimated rainwater harvested with your water usage needs. The cistern size should be large enough to meet your water demand during dry periods between rainfall events.

As an example calculation:

Cistern Size=(Roof Area×Average Annual Rainfall×Efficiency Factor)−Water Usage NeedsCistern Size=(Roof Area×Average Annual Rainfall×Efficiency Factor)−Water Usage Needs

Keep in mind that these are general guidelines, and it’s essential to tailor the calculation to your specific conditions and requirements. Consulting with a local water conservation or rainwater harvesting expert can provide valuable insights for your particular situation.


4. Pump System:

  • Submersible Pump: Use a submersible pump in the cistern to pump water to the catchment area. (Can use the Bellagio pump we initially got for the goldfish tank.)
  • Float Switch: Include a float switch to control the pump automatically based on the water level.

A float switch is a type of level sensor, a device used to detect the level of liquid within a tank. The switch may be used to control a pump, as an indicator, an alarm, or to control other devices. One type of float switch uses a mercury switch inside a hinged float. 

5. Catchment Feature:

  • Fountain or Shallow Pond: Choose a visually appealing catchment feature that promotes water circulation.
  • Aeration: Consider adding an aerator to prevent stagnation and improve water quality.

Such As:
AquaMiracle Pond Aeration Kit Koi Pond Aerator Pond Air Pump for Pond up to 15000 Gallons Pond Deicer All-in-One Pond Aeration System with Self-Sinking Airline Flow Control Rubber Air Diffuse: $149 (Amazon)


6. Overflow and Pressure Equilibrium:

  • Overflow Outlet: Install an overflow outlet at an appropriate height in the cistern to prevent overfilling.
    • An overflow outlet is a component in a water storage system, such as a cistern or a rainwater harvesting system, designed to prevent overfilling and potential damage. It provides a controlled pathway for excess water to exit the system once the storage capacity is reached.
    • In the context of a rainwater harvesting system with a cistern, the overflow outlet is typically positioned at a specific height within the cistern. When the water level in the cistern reaches this predetermined point, any additional water flows out through the overflow outlet.
    • Key features of an overflow outlet:
    • Prevention of Overfilling: The primary purpose of the overflow outlet is to prevent the water storage system from overfilling, which could lead to flooding, structural damage, or other issues.
    • Controlled Discharge: The overflow outlet allows for a controlled discharge of excess water. This helps avoid sudden and uncontrolled releases that could cause erosion or other problems in the surrounding area.
    • Protective Measures: Installing an overflow outlet is a protective measure to ensure the integrity and longevity of the water storage system.
    • Outlet Design: The overflow outlet can take various forms, such as a pipe or a channel, depending on the system’s design and requirements. It may discharge water to a designated safe area or drainage system.
    • When designing a rainwater harvesting system or any water storage system, it’s crucial to include an overflow outlet at an appropriate height to manage water levels effectively and prevent overflows. This feature helps maintain the stability and functionality of the entire system while avoiding potential damage to surrounding areas.
  • Pressure Relief Valve: Use a pressure relief valve to maintain pressure equilibrium and prevent damage to the system.
    • A pressure relief valve, also known as a pressure release valve or safety valve, is a critical component in various systems to protect them from excessive pressure. The valve is designed to automatically release or relieve pressure when it exceeds a predetermined set point. This helps prevent damage to the system, ensuring its safety and proper operation.
    • Key features of a pressure relief valve:
    • Set Pressure:
      • The valve is set to open and release pressure when the internal pressure of the system reaches a certain level. This predetermined pressure is known as the “set pressure” or “set point.”
    • Automatic Operation:
      • The pressure relief valve operates automatically without the need for manual intervention. When the pressure surpasses the set point, the valve opens to allow excess pressure to escape.
    • Safety Function:
      • The primary purpose of the pressure relief valve is to protect the system from potential damage caused by overpressure. This is crucial in applications where maintaining a specific pressure range is essential for the system’s integrity and safety.
    • Various Designs:
      • Pressure relief valves come in various designs, including spring-loaded, pilot-operated, and rupture disk types. Each design is suited to different applications and pressure conditions.
    • Installation Location:
      • Pressure relief valves are typically installed at strategic points in a system where pressure buildup is a concern. For example, they may be found in steam boilers, water heaters, pressure vessels, and other industrial or plumbing systems.
    • Certification Standards:
      • Pressure relief valves are often subject to industry standards and regulations. Ensuring that the valve complies with relevant standards is essential for maintaining system safety.
    • In the context of your rainwater harvesting and storage system, a pressure relief valve could be used to manage pressure within the system, especially if you are incorporating a pump. It helps prevent overpressurization, which could lead to equipment failure or damage. When designing your system, consult with professionals to determine if a pressure relief valve is necessary and the appropriate specifications for your specific setup.

7. Maintenance:

  • Regular Inspection: Periodically inspect the system for clogs, leaks, or any issues.
  • Clean Filters: Clean cistern filters and pump intake regularly to ensure efficient operation.

Additional Tips:

  • Rainwater Quality: Keep in mind the quality of rainwater; it may need additional filtration for greenhouse use.
  • Solar Power: Consider using solar-powered pumps for sustainability.
  • Professional Assistance: If needed, consult with a local engineer or landscape professional for specific design considerations.

Water Temperature and Fish Health

It’s important to keep our aquariums within a certain temperature range to make sure the fish and other aquatic creatures we keep are happy and healthy. Too high or too low, and our aquatic pets will suffer. The temperature range that’s best for each creature depends on what part of the world they’re native to. Tropical fish, for example, do best between 75° and 80°F, goldfish and other “cold-water” species prefer temperatures below 70°F, and temperate fish can be found in habitats that overlap tropical and cold-water realms.

Fish are cold-blooded – aka ectothermic or poikilothermic – animals, meaning they cannot control their body temperature. Instead, they rely on the temperature of their environment to regulate their metabolisms and activity levels. When it’s too cold, they’re less active, their appetite is reduced and their immune systems are compromised, making them more susceptible to disease.

When it’s too warm, their metabolisms and breathing speed up, and they use more oxygen. The problem is, as water warms up it holds less oxygen, which further stresses the fish. Once again, they become more susceptible to disease, and in extreme cases, they can experience organ damage or even suffocate. Making matters worse, above 90°F, the beneficial bacteria that maintain balance in an aquarium begin to die, creating the potential for dangerous ammonia and nitrite spikes.

In the Wild

Water temperature in nature isn’t always constant. In fact, it can fluctuate quite a bit. Some days are sunny, some are cloudy. There may be seasonal changes as you get further away from the equator. Sometimes it rains, which can cool things down considerably. The water near the surface is usually quite a bit warmer than just a few feet below. And what happens when the sun goes down at night?

There are two major differences between natural habitats and our aquariums when it comes to temperature. First, fish in the wild can usually move to a more desirable spot if they don’t like the temperature. And second, temperature changes tend to occur gradually in nature due to the massive volumes of water involved, so fish have time to adapt, or move. Not so in an aquarium.

In the Aquarium

Unlike nature, where water temperature can vary in different micro-habitats, the temperature in an aquarium tends to be uniform throughout the tank. Aquarium fish can’t move from a less favorable spot to one that’s more comfortable if the temperature is outside their preferred range. In addition, temperature changes are often more extreme and happen much more rapidly in an aquarium, giving our fish less time to adapt.

Fish that are kept at the wrong temperature long-term may not grow as large, their colors may be muted, they may be less inclined to breed, and they may not live as long. A sudden drop in temperature is often linked to the onset of Ick and other parasite outbreaks.

Maintaining Proper Temperature

Now that we understand how important maintaining proper water temperature is for our fish, let’s look at how to achieve it:

  • Avoid placing your aquarium near sunny windows, exterior doorways, heating and air conditioning vents, fireplaces and drafty areas that can affect water temperature.
  • Choose a quality heater that is designed for your tank size.  (Large aquariums may require more than one heater.)  Use the Aqueon Heater Guide to select the right size heater for your aquarium.
  • Make sure there is adequate circulation around your heater to ensure even heat distribution.  (This will also prolong the life of the heater.)
  • Install an accurate thermometer and check it regularly to make sure your heater is maintaining the right temperature.
  • When performing water exchanges, match the temperature of replacement water as closely as possible to your aquarium.

Heating an aquarium is relatively straight-forward, but what happens when hot weather makes your aquarium too warm? Dialing the A/C down a few notches can be expensive, and what if you don’t have air conditioning? An easy solution is to open the tank lid and direct a fan across the water surface to create evaporative cooling.  (Lower the water level slightly to prevent fish from jumping out.)  Aquariums with cold-water fish or sensitive corals may require a chiller. For additional tips on cooling your aquarium, visit How to Keep Your Aquarium Cool in Summer Heat.

Mixing Different Fish

When stocking your aquarium, choose fish whose preferred temperature ranges match the temperature of your tank. Things can get a little tricky, however, when the upper limit of one species coincides with the lower limit of another. Trying to find a happy middle ground may stress both fish because one is always a little cold, and the other is a little warm. While they may tolerate the situation, neither of them will thrive. Always set your heater for the middle of your fishes’ preferred temperature range and choose fish that share the same temperature requirements.

Maintaining a stable temperature that matches your fishes’ needs isn’t difficult, and your fish will thank you for it!

Source: https://www.aqueon.com/

How to Cycle a New Tank

By far the most tedious aspect of owning an aquarium is the initial setup. This involves setting up the pumps, filters, and decorations before adding appropriately filtered water. Once the tank’s components are put in place, the longest of setup processes, cycling, is ready to begin. Aquarium cycling is often overlooked by beginners who wish to see their tank alive, but it is a crucial step in creating an environment for happy, long-living fish. Below you can find information on what cycling is, why it is important, and how to cycle your aquarium.

What is aquarium cycling?

Aquarium cycling is the process of creating a biologically safe environment for fish in a new tank. It involves introducing nitrifying bacteria into the aquarium to regulate the nitrogen cycle. These bacteria curb the effects of ammonia buildup caused by the breaking down of fish waste. To complete the nitrogen cycle, ammonia must be converted to nitrite, and the nitrite must be converted to nitrate.

Why do aquariums need to be cycled?

Before fish are introduced into the environment, nitrifying bacteria must spread themselves across the aquarium’s biological filters to handle the volume of ammonia produced by the fish. If fish are introduced to the tank too quickly or if too many fish are introduced at once, the biofilters will not be able to keep up with the amount of ammonia produced by the fish. Even after cycling an aquarium properly, it is best to introduce your fish one at a time to ensure the tank is biologically prepared for more fish.

If you do not cycle your aquarium, the nitrogen cycle will still occur, but your fish will likely be harmed in the process. The effects of built-up toxins in a new aquarium contribute to what is known as “New Tank Syndrome.” Species of fish that are not hardy are more prone to symptoms of ammonia exposure and require a cycled aquarium to live healthy lives.

How long does an aquarium take to cycle?

Aquariums generally take four to eight weeks to cycle. Factors such as the size of the tank and the water’s pH and temperature can affect how long cycling takes. To prevent the cycling process from taking longer than necessary, closely monitor the temperature and pH of your aquarium’s water. The pH should remain between 7.0 and 7.8, while the temperature should maintain a range of 83°F to 87°F. Not only does this expedite the tank’s cycling, but it will also ensure the stability of the environment the fish will live in. You should also test the tank’s ammonia, nitrite, and nitrate levels every one to two days when cycling your aquarium. If the aquarium is cycling properly, you will first notice a drop in ammonia and a significant spike in nitrites. Once the nitrite levels are high enough, nitrate-producing bacteria will begin populating the tank. Once these bacteria populate the tank, nitrite levels will fall. Once the ammonia and nitrite levels reach zero and nitrates are being produced, the cycle is complete.

coral fish tank

What do I need to cycle an aquarium?

Before cycling an aquarium, ensure you have the following items available:

An aquarium cannot be cycled until it is equipped with all of the components it requires to house the fish. Certain water contaminants, such as chlorine and chloramine, affect the nitrogen cycle and the water’s PH, so a quality water filter is necessary when filling your tank.

Learn more: Why you should use reverse osmosis water for your aquarium

How to cycle an aquarium

When cycling your aquarium, you have the option to cycle without fish, with fish, or with plants in the tank. It is highly recommended that you cycle your tank without fish, especially if you are a beginner. Fish in the tank during this process are exposed to higher-than-normal levels of ammonia, and even hardy fish can suffer as a result. Plants, on the other hand, are unpredictable and can lead to frustration when cycling a tank.

Cycling without fish

Cycling an aquarium without fish is more time-consuming than cycling with fish, but it is also more humane. Consequently, it is the more popular way to cycle an aquarium. Note that you should introduce fish with this method once your aquarium shows signs that it has cycled.

1.  Set up the tank’s components

Before cycling the tank, you must ensure that the pumps, filters, substrate, and other tank components are set up and functioning properly. While the aquarium is cycling, all bubblers, heaters, pumps, and filters should be kept running. This allows nitrifying bacteria to accumulate on the surfaces of the aquarium, particularly the filters and substrate. The bacteria that cling to these surfaces reproduce and maintain the nitrogen cycle when fish are added to the tank.

Learn more: What is an aquarium air pump? | What is an aquarium water pump?

2.  Check the water’s pH

Maintaining a pH of 7.0-7.8 is ideal for the nitrogen cycle to occur the most efficiently. It is also the perfect pH for most freshwater fish. Water that is too acidic (pH of less than 7.0) is particularly detrimental to the nitrogen cycle because it allows ammonia levels to rise when it is not wanted. Chlorine, a chemical present in tap water, drops the pH of water below desired levels. In contrast, too high of a pH is also detrimental to the nitrogen cycle. When the pH rises above 9.0, ammonium converts into ammonia, disrupting the tank’s environment. Throughout the whole process of cycling and after fish are added to the aquarium, it is important to check and maintain the water’s pH to preserve the health of your fish. The pH of water can be tested with pH test strips or an all-in-one test kit.

3.  Add ammonia to the tank

To begin the nitrogen cycle, ammonia must be present in the tank. A simple and effective way to raise ammonia levels in an aquarium is by adding fish food. You should add the amount of food that you would if fish were present in the tank. If you plan on incorporating six fish in your tank, for example, you should add an appropriate amount of food for six fish. When the food decays, it releases ammonia into the water, kickstarting the nitrogen cycle.

4.  Check ammonia levels

Once the food decays, check the ammonia levels of the water. The ideal ammonia concentration in a tank is about 3 parts per million (ppm). Ammonia levels as high as 5 ppm are acceptable, but fewer than 3 ppm of ammonia may fail to produce enough nitrite to properly cycle your tank. If the ammonia levels are too low, add more fish food, allow it to decay, and check the levels once more. If the ammonia levels are too high, change out about 10 to 20 percent of the tank’s water with treated water.

Check the ammonia daily for one week and add food if the ammonia drops below 3 ppm. Likewise, perform a water change if the ammonia rises above 5 ppm. Ammonia, alongside pH, nitrites, and nitrates, can be checked with an aquarium test kit.

5.  Check nitrite levels

Once the water has maintained appropriate ammonia levels for a week, the nitrite levels in the tank should be detectable. If nitrites are not detectable yet, allow a little more time and continue to monitor the ammonia levels and pH. Once nitrite levels begin to rise, they will spike quickly as there is nothing to regulate them yet. The nitrites feed on ammonia, so you must maintain ammonia levels during this stage as well. If the ammonia runs out, the nitrates can disappear, and you will need to start the cycle over again. Once the nitrite levels begin to drop while the ammonia levels are suitable, you can move on to the next step.

6.  Check nitrate levels

When nitrite levels decline in a tank, that is a sign that either nitrifying bacteria are feeding on the nitrite or that ammonia levels are too low. If nitrates are detectable in your tank, that is a sign that the nitrite levels are declining due to the presence of bacteria. Once nitrate levels are detectable, it is the beginning of the end of the cycle. To ensure the bacteria have enough to feed on, add half as much fish food as you did on the first day about once every two to three days. You should notice that the ammonia and nitrite levels continue to decrease. Once the ammonia and nitrite levels reach zero and the nitrate levels remain, the tank has finished cycling.

7.  Introduce fish into the tank

Once the tank has finished cycling, incorporate fish into the tank slowly. To begin, add one or two fish so the bacteria do not become overwhelmed. After a day or two, check the ammonia levels in the tank. If they remain at zero, you can incorporate more fish into the aquarium. Continuing to monitor and regulate the ammonia, nitrite, and pH levels of the aquarium is essential in maintaining the health of your fish.

Learn more: How to maintain a freshwater aquarium

Cycling with fish

Cycling a tank with fish is similar to cycling a tank without fish, but the source of ammonia differs. Rather than adding food to the water, the fish provide ammonia in the form of waste. In addition, you will need to perform frequent water changes with fish present. Fish-in cycling is not recommended in most situations, but it can be effective if you populate your tank with hardy fish.

two fish in tank

1.  Set up the tank’s components

This step is identical to step one of fishless cycling. Before you add fish to your tank, ensure all components are installed properly and are in working order. This includes all pumps, filters, bubblers, temperature regulators, and all other components. This creates a suitable environment for your fish to live in.

2.  Add a few hardy fish to the tank

Hardy fish are less affected by ammonia and other contaminants than most fish species, so they are the only suitable type of fish to be in the tank while cycling. Do not add more than three fish to the tank. If too many fish live in the tank during the cycle, they will produce too much waste and cause ammonia levels to spike too high.

3.  Feed the fish

Once the fish have been added, you will want to feed them sparingly. This can mean feeding them less frequently or feeding them smaller amounts at a normal frequency. Avoid overfeeding the fish, as this will cause them to produce more waste and lead to the additional production of ammonia via decayed food. Once the cycle kicks off, you can begin feeding the fish regular amounts of food.

4.  Perform water changes

Change about 10 to 20 percent of the tank’s water twice every week. This helps regulate ammonia, nitrite, and other contaminants’ levels. Water changes of this frequency should continue as long as your aquarium operates.

5.  Monitor contamination levels

While making water changes, you will need to constantly monitor the tank’s ammonia, nitrite, and nitrate levels. Once the nitrate levels remain consistent and the ammonia and nitrite levels are undetectable, the cycle has been completed. Additional fish can then be added to the tank.

Cycling with plants

Aquarium cycling with plants is far less predictable of a method than fishless and fish-in cycling. Plant death and algae growth can cause the cycle to fail and require you to start the process over. As a result, this method is not recommended over fishless cycling, but it is more humane than fish-in cycling. Before cycling a tank with plants, you will need to purchase nitrogen-containing fertilizers.

planted aquarium

1.  Setup the components of the aquarium

Like step one in the previous methods, ensure that all pumps, bubblers, filters, heaters, and other components are added to the aquarium.

2.  Disinfect and add plants to the aquarium

Before adding plants to the aquarium, disinfect them to reduce the risk of outside bacteria and parasites from harming the tank’s environment. Hardy plants are the best plant type to add to an aquarium while cycling. Water column feeders are ideal because they absorb ammonia and nitrate better than other plant types.

3.  Incorporate aquarium lighting

The lighting of a planted aquarium is essential in allow the plant to photosynthesize. Ensure that the lighting setup you use is optimal for your plants both while cycling and after. At this stage, plants should receive about ten to twelve hours of light per day.

4.  Add fertilizer

Now that the lighting is set up, you can add fertilizer to the tank. If you are using water column feeders, liquid fertilizer is the best option. For root plants, place root tabs directly under the plants’ roots.

5.  Perform water changes

When cycling with plants, you should change about 30 percent of the tank’s water each week. This reduces algae growth, especially in the first few weeks after introducing plants to the water.

6.  Watch for new growth

If you see new growth in your tank, that is a sign that the tank is completing its cycle. You may notice some algae growth along the tank walls and substrate. In this phase, some algae growth is acceptable because it signals there are enough nutrients for the plants to thrive. If your tank has an abundance of algae, lower the lighting duration to about eight to ten hours a day.

7.  Monitoring the water contamination levels

Throughout this process, you will need to monitor the ammonia, nitrite, and nitrate levels of the aquarium’s water. To test if your tank is cycled, add around one ppm of ammonia to the tank. If ammonia levels are undetectable after 24 hours, nitrites are undetectable, and nitrates are present, the tank has completed its cycle.

Can I cycle an aquarium in 24 hours?

Adding bacteria manually can help a tank cycle quickly, but it can lead to problems for your fish later on. If you choose to speed up the hydrogen cycle in your tank, you will need a filter and substrate from an already cycled tank to produce the most desirable results. While bottled bacteria and recycled filters and substrate speed up the nitrogen cycle, the best option for your aquarium is to let the process carry out naturally.

Source: https://www.freshwatersystems.com/blogs/blog/how-to-cycle-a-fish-tank