Pool Pump for a Waterfall Pump?

1. The WhisperFlo comes with an inbuilt strainer. For removal of twigs and dead leaves it's good enough.
2. As long as the wetted parts of the pump are non-metallic or at least coated in some non-metallic substance, brackish or even seawater will not damage it.
3. If you're using a submersible pump, ensure that it's cleared frequently; they have an annoying habit of causing dead leaves to accumulate around the intake. When this happens, the pump will dry run and burn out its motor. Wrap a fine nylon mesh around the inlet if you're concerned that it may suck in debris that can damage the pump. It goes without saying that you'll need to clear it more frequently if you do this, as bacterial slime growth can foul it to an extent that will affect the pump adversely.
4. For sizing the pump, your flow rate will depend upon your required pond turnover rate. Allow for at least 20 minutes contact time with your biofilter.

Think I answered all your questions. Hope this helps.

I recently completed a 5500 gal. Koi pond. There are many considerations. My best recommendation is to visit the POND DOC web site. They know everything!

This WF-4 is a standard centrifugal pump with a nice suction chamber on it. This kind of pump can work at any flow rate all the way back to maybe 10% of the rated 120 gpm simply by closing a valve on the discharge line until a desired lower flow rate is achieved. At 10% the power used will be somewhere in the range of 50% to 75% of full flow power. This is a way to use that pump and save a little on your electric bill. But I'm thinking if you really need only a quarter or half of that flow amount you'll save on electricity consumption in the long run by getting a pump that is rated for the flow rate you really need and has a smaller hp electric motor. If the guy who sells you another smaller pump knows anything he should be able figure just how much the smaller pump will save in electricity usage with the information from his pump data sheets and some simple calculations. Or get the data sheets with pump performance curves from the manufacturer and find someone that can do some easy engineering calculations to help you.

Ed Weldon

I'd check out a pump made by a company called Rule - they build a submersible unit with a permanent magnet motor that draws only one amp or so at 115v. It has a strainer and is mostly plastic. It will pay for itself in reduced energy costs in no time. They are also in the bilge pump market (boats) and manufacture 12volt DC units that could be used with a battery/solar setup.

Edmund

A lot of these little pumps will only pump up to 4-5 feet head. If 12-15 feet is the actual height and not partly friction losses in small lines a bigger pump will probably be all that will work. The bilge pump might work; but will it hold up year after year on even an 8-10 hour per day duty cycle? That's not what they are really designed for.

A neighbor of mine got a yen to put a 6 foot high fountain in the middle of his garden. He only wanted a flow rate on the order of a gallon of two per minute. Couldn't find a small quiet submersible pump that could do that with any kind of efficiency that he was willing to accept. He finally found one that would pump up to 4 feet; so the top of the fountain is dry except during the rainy season.

Ed Weldon

My experience with Rule in Marine applications suggests they are a bit challenged in the reliability arena. It appears they tend to use cheaper wire insulation on their power leads that allows the wire to corrode far too rapidly for long-term reliability. I tend to avoid that brand for this reason. Unfortunately, they also own Jabsco (or is it Jabsco that owns Rule?), which seriously limits the choices available for marine applications. They also tend to be far more expensive than what are sold as "fountain pumps"- anything with "Marine" in the name or specification is going to carry a price premium...

I went through this about 20 years ago. The most important calculation is to multiply the power consumed by the cost of electricity in your area to get a cost of running the fountain in terms of $ per hour and also look at the cost per month based on several scenarios of run time per day. Electricity in Houston runs $.14 to $.27 per kilowatt hour depending on your provider and contract.

I had a friend who wanted to run his fountain all the time, but the 100 GPM pump didn't provide the architectual effect he was looking for. Thankfully we explored the cost before purchasing larger pumps.

You can get a good idea of the flow rate from a hose with a stopwatch and a 5 gallon bucket. Then look at that flow rate on your proposed scenery.

Some thoughts:

This type of pump would require that the pump either be installed below grade (to flood the inlet) or have suction lift with a check valve to maintain prime. A check valve requires relatively clean water.

The strainer basket could serve as a secondary strainer but you would have to install some sort of system for primary inlet straining. These systems are commercially available. You should consider a piping system that would allow you to back-flush the primary strainer, using valves.

To install below grade would mean you would have make sure you had adequate drainage around the pump in case of a seal failure, pipe system problems and seasonal drainage to prevent freeze damage.

The website shows multiple motor sizes available for a given model, but only one impeller, so I assume you could downsize the motor if nessecary, as it has a standard square flange.