When you had your water feature installed, you trusted your contractor to know enough about water flow and pond building to make sure that your backyard paradise would run smoothly, and he did an amazing job. Not once did it ever occur to you to ask him what kind of pump or plumbing he used while finishing the job. Why not? The retailer that sold you the pond kit told you that you had the perfect size pump for the job, but how do you know?
Not many people want to get involved in the “mechanics” of a pump because it can be too difficult to understand. With terms like TDH, GPH, and flow rate, who can blame you for wanting to turn a deaf ear to the ins and outs of pumps as they relate to your pond? The truth is, knowing a bit more about your pump and plumbing can actually help you understand the living, breathing ecosystem that lies beneath the surface of the water. Most importantly, it can help you solve problems and navigate through situations a little easier.
Learning about pumps and plumbing in plain English can be valuable for people who’d like to know more about their water feature, or for prospective pond owners looking to learn a little bit more. To start off, you’ll want to educate yourself on the purpose of the pump in relation to your pond’s ecosystem. Pumps and plumbing make up the circulatory system of a water feature and are extremely important when it comes to the aesthetics of your pond. More importantly, they supply the system with necessary oxygen levels and keep the water circulating.
There are several different types of pumps to consider – from swimming pool pumps to the common sump pump you find in your basement. According to some experts, sometimes just the variety of pumps that are out there can confuse potential water gardeners. Pumps made specifically for water gardens are definitely the way to go. In fact, information about what kind of system the pump will fit is usually right on the outside of the box.
All of the specifications should be available so that you are aware of what kind of performance you’ll get out of the pump. But what are specifications, and what do they mean to you? Plenty.
Specifications can mean the difference between a gushing waterfall and a trickle that sounds like a leaky faucet. That’s why it’s so important to learn the meaning of each one and what they’ll do for your pond. Let’s start with the acronym GPH, meaning gallons per hour. The term “gallons per hour” represents how many gallons that pump is circulating every hour and can also be referred to as “rated flow.” Other terms listed are volts, watts, and amps, which basically represent your voltage, electrical power, and current, respectively.
Then there’s shut-off height, which judges the amount of elevation change a pump can take to pump water. For example, some pumps may not work with your 20-foot waterfall and this is a way to find out without having to field test it. Perhaps the most confusing phrase is total dynamic head (TDH). Total dynamic head refers to the pressure on a pump caused by the interactions of flow rate, pipe diameter, pipe length, elevation, and pipe material. Basically, it takes all those things into account and lets you know the limitation of your pump. TDH is usually calculated by a pond professional.
If you aren’t convinced that knowing a bit about your pumps and plumbing is important, the term “operating cost” may perk your ears up a bit. This is where you find out how much your pocketbook gets hit.
Obviously, the bigger your pump, the larger the operating cost per month, but you should also be aware that some pumps have a lower operating cost than others. Seek out the high-efficiency kind. The basic difference between the two is the motor. High efficiency pumps use less power. It’s important to note that operating costs are based on a median number, however, so it isn’t exact but will be very close.
If all that lingo makes you even more confused, perhaps things will clear up once you start relating the terms to your own pond. Establishing the flow rate is probably the most important thing to do when it comes to your waterfall. Experts say that for each foot of spillway width (the width of the initial waterfall drop), you should allow 1500 gallons of water flow. For example, a 2-foot wide waterfall usually requires a 3000-gph pump.
The flow rate helps ensure that you have enough water to cover the entire width of your waterfall and stream. This rate provides an attractive amount of water, so it’s not overpowering and not just a trickle. Most people believe that a pump rated at 3000 gph will always push that amount of water. That’s where waterfall and stream height factor in and the term “shut-off height” comes into play. Once you subject your pump to higher waterfalls or longer streams, it will push less water. Once it reaches that shut-off height, you won’t see any more water…a pretty important statistic when you put it in plain English.
The plumbing that is used with pumps is also an important part of the equation. Using the wrong pipe can cause friction, hindering the performance of your pump and affecting the power of your waterfall. The type of pipe you choose is also important to the function of your water feature. With so many different types of pipe on the market – from schedule 40 pvd to poly pipe – it’s hard to tell which will work for a water feature.
Flexible pvc is a popular choice for pond projects. The research and development team at Aquascape, Inc. credits the pool and spa industry for flex pipe. Not only can it handle sharp turns and tight corners, but it also expands and contracts with seasonal changes – a great plus for those of you in the cooler climates.
Something you’ll definitely want to invest in when it comes to keeping your pond functioning correctly is the check valve. The check valve helps prevent water from draining back into the pond when the power to your pump is cut. The reason this is important is because you need to keep water in your biological filter so that the beneficial bacteria can continue to grow. Without the water, the bacteria can die and throw off the balance of your ecosystem. And no one wants to see the return of the dreaded algae.
So what now? What can you do with all the extra information you’ve learned about pumps and plumbing? Well, you can rest assured that if anything happens to your pump, you’re not at the mercy of the retailer or contractor that sold or installed your pond. You can sit back and relax with your favorite book by the pond … now that you really know everything you need to know about your water garden pump.
For more information on pump maintenance, watch our short video: