Water Testing and Dosage Calculation

Water Testing and Dosage Calculation for Irrigation-Based Landscape Care Products

Testing a customer’s water supply can provide valuable information about the underlying causes of recurring problems such as rust stains and a white film on wilting plants. The results can inform your choice of products to target these issues at the root and minimize the number of maintenance calls that have you returning to the property. 

However, water quality can change frequently, and we recommend that you test a water supply once a year to monitor changes in iron, hardness, and pH levels. 

The Importance of Iron Content

Water containing elevated levels of iron can appear clear and be relatively non-hazardous to humans. However, when the soluble iron interacts with the open air, it can form reddish-brown or orange rust stains on surfaces like driveways and walkways. Well water commonly contains elevated levels of iron and is often the culprit behind these unsightly stains on properties. Iron-containing water can also promote the flourishing of iron bacteria, which produce a slime-like film that can clog pipes and screens, leave stains on laundry and fixtures, and cause an unpleasant taste or odor.

The Importance of pH

Referring to the acidity or alkalinity of the water, pH can influence the ecosystem in which plants grow in various ways. Acidity influences the solubility of nutrients and how easily they can be absorbed, the breakdown of organic substances, and the balance of micro-organisms in the area. Finding the right pH levels to suit a particular property’s plants and soil conditions often relies on experience and experimentation, and there are various signs that may indicate a pH imbalance. 

How to Test a Water Supply






There are various ways to test a water supply. You can use our do-it-yourself water test kit containing all the necessary materials to conduct two tests each for iron content, pH level, and the hardness of a water supply, with easy-to-follow instructions included. 

Testing is conducted on a sample of water taken directly from the sprinkler head. Testing the pH level and hardness is as easy as dipping a strip of litmus paper into the sample and comparing the color result to an included chart. To test the iron content of the sample, add a reagent to the sample, and compare the color of the water to the included chart. 

Alternatives to do-it-yourself testing include sending us a 4-ounce sample of water taken directly from the sprinkler head, which we can test for you. You could also approach a local water testing source to test the water. 

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How pH & Iron Content Influences Your Choice of Product

The pH level of water can influence the product you choose to tackle the problem of rust stains on a property. For example, Rid O’ Rust Rust Preventer formulas target rust stains at the root cause by neutralizing the iron in well water. The product is injected into an irrigation system before the point of oxidation where the water is exposed to oxygen. The version for extreme water is reserved for irrigation systems with low or fluctuating pH, which makes information about the water pH very helpful in choosing the most effective product. 

There are various other potential culprits behind rust-like stains besides iron, including certain fertilizers and tannins. Products like Rid O’ Rust, which neutralize iron, do not target tannins. So, it could prove to be a waste of time and money to purchase an iron-neutralizing product to tackle stains before having confirmed iron to be the cause. 

The iron content of a customer’s water supply will also inform whether you can use Rid O’ Rust Rust Preventer with the handy GreenFeeder System, as the iron content would need to be below 2 ppm. In cases where the GreenFeeder cannot be used, the Rid O’ Rust Feeder System is the go-to automatic injection system to incorporate the product into the unoxidized water supply. 

How to Calculate the Right Dosage of Product

Rust prevention products, as well as liquid fertilizers and pest repellents, can be administered to a property through the irrigation system by being added to an attached feeder system. Feeder systems include automatic injection systems and siphoning systems, and are designed to add a small regulated amount of product to the water moving through the irrigation system. This is performed at specific time intervals and at a specified flow rate. Keep in mind, to ensure that the automatic distribution of product is perfectly regulated, the correct dosage of product must be added to the system. 

When calculating the correct dosage of Rid O’ Rust Rust Preventer, for example, the iron content and pH level, which have been discovered by testing the water supply, are important parameters to include. To calculate the correct dosage for your customer’s irrigation system, you could use our online dosage calculator or send us the water test results alongside specific information about the irrigation system for a personal recommendation. 

If you’re using the online dosage calculator, you will need to specify certain other parameters in addition to the iron content and pH level you retrieved from testing the water. These include the flow rate of the irrigation system in gallons per minute, the output of the pump in gallons per day, and the size of the tank being used. Some of these can be estimated. 

When calculating the right dosage of Rid O’ Rust Rust Preventer, for example, it is important to distinguish between the use of an injection system and siphoning system for the widespread distribution of the product via the irrigation system. An injection system utilizes a metered pump, the GPD of which will affect the required dosage of product. GPD refers to the gallons of fluid the metered pump moves per day and, depending on the model of the pump, may be indicated somewhere on the equipment. The calculated dosage will usually apply to a pump with the dial set to 5 or 50%. 

The flow rate of the irrigation system in gallons per minute is also important, but can be estimated by finding the zone containing the most sprinkler heads and multiplying the number of sprinkler heads within the zone by 3. For a more accurate flow rate, you could consult an irrigation specialist. The size of the stock tank from which the system is drawing the concentrated product is another crucial variable to calculating the dosage of product that you will need to add to the system. 

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