Pond / water feature pump advice please

Hi all.

We're building a new pond with a small waterfall.

The pond is dug out. The liner is on order. I have nice stones ready to build the small waterfall. I'm just stuck a bit when it comes to pumping the water.

I thought about going for a low voltage pump, to avoid taking mains power to it. eBay has plenty of pumps, and I know how to calculate required flow rates etc. I just can't seem to get a straight answer on required pipes and connectors and such.

Any advice?

 

I'd get the pump and then sort out the pipe dia required from what the inlet and outlet diameters are.

 

I’ve never encountered low voltage pumps, but my guess is that they won’t have much ‘oomf’. With that in mind, I’d be looking at something with at least 50% more capacity than you think you’ll need. If you get one with a variable control, you can always turn it down to the required rate. The pump should come with a hose tail fitting, so you just cut down to the required diameter. I’d have thought 32mm pipe would be ample. Sorry, can’t help with the rest.

 

I've never tried a low voltage pump either, I do wonder if you put a large dia pipe on the outlet at some point it will actually reduce the flow, there must be an optimum size for the power of the pump.

How you work that out is beyond me, probably a mathematical formula, I just try things and if it works go with it.

 

I don’t imagine he’s looking for a torrent @pete , which is why I suggested 32mm, pretty much the smallest (sensible) size you can get.

PS, there is no inlet pipe as water will be drawn in through the pump body.

 

Yeah of course but my pump still has an inlet which you can put a pipe on if you want to.

32mm is bigger than I have, mine is 25mm, I think, I just used that clear smooth pipe and buried it, but it goes to an external filter box which is higher than the top of the waterfall and gravity takes it back down.

Its just been cobbled together over the years but seems to work reasonably well.

 

Ah yes, just checked and indeed smaller sizes are available. 25mm would probably suit

Premium Spiral Pond Hose

 

Lots of interesting stuff there @Freddy connectors ETC.

 

As an aside, @Clueless 1 v2 hasn’t said if he intends to keep fish/wants a filter.

 

I noticed that they have an inline flow regulator. Not cheap, but might be useful if the pump doesn’t have a flow control. I believe a lot of them do though.

 

We don't plan to put fish in it. I'd like to, but I'd be worried that the local cats would have them.

I thought about a filter, mainly just to help keep the water clear. To be honest I was going to scrimp on that bit. I saw a YouTube video where a guy just had an old bath sponge in an old margarine tub and pumped the water through it. I thought for my purposes that might suffice, unless you tell me otherwise.

 

How big is the pond @Clueless 1 v2 .

My filter is a bit more than a sponge in a margarine tub but probably works on a similar principle.

 

Off the top of my head, I believe some of these pumps come with a sponge filter inside. This isn’t ideal as every so often they become clogged and have to be cleaned out (meaning you’d have to get the pump out of the pond) . How often is dependent on what’s in the pond. Fish, plants and any run-off from surroundings will all have an impact. Of course, if these aren’t an issue, then cleaning will be minimal. It might be an idea to remove the pump filter (if there’s one inside) and setting up an external filter. It only needs to be rudimentary, basically a plastic box with some sponge in it, with an inlet and outlet. Just be careful to allow for overflow should the sponge become blocked, otherwise it’s possible for all the pond water to be lost (unless it’s a sealed box). Another issue might be algae. You could use plants to help control this, I’ve heard barley straw can also help. This though will mean more pump cleaning if you don’t have an external filter. In the ponds I’ve had I used a good quality U/V to control this, but you’d need mains electricity for that, I think (?). Much will depend on where the pond is sited, a shaded spot is best.

 

My pump is contained inside a plastic cage, just to stop weed getting sucked in, the filter is just a black plastic box filled with plastic bits with three foam layer on top.
I put an overflow pipe on the top well above the foam to take water directly back into the pond when the foam blocks up.
The plastic bits are supposed to work as a biological filter.

 

This raises an important issue. Unless the external filter is sealed/pressurised, the outlet/return pipe needs to be a larger diameter than the inlet pipe. For an inlet pipe diameter of 25mm, I’d suggest an outlet diameter of 50mm.