Everything these is to know about submersible pond pumps

As you struggle for the seeming billionth time, after extracting your submersible pump from the wretched cold muck and mire and you are trying to prize off the clogged up jet to clear it of yet more detritus, it might cross your mind who might have spawned this travesty of uselessness. The truth is it may be something to do with the task you have set it to do. 

It does seem possible that occasionally someone has been asked to design something that would be cheap to produce, but in general the designers in the pond pump industry (for there is one) are more than keen to fulfill all the expectations we have of submersible pond pumps. The result is that pond pumps have been redesigned with ‘a look’ that suggests purpose and efficiency. The fact that most small pumps come with a fountain jet and fittings for variable flow seems to attest that at least the pump is suitable for producing a fountain if nothing else. Well, we shall see.

We asked a number of leading manufacturers what they had in the way of ‘fountain pumps’ for testing against other makes. We were not after the very tiddly ones, but something that would create a decent splash in a largish pool or run a reasonable sized ornament. I said that about 1000 litres to be pumped to a height of roughly a metre. Well that is what I said to the editor and by the process of Chinese whispers I ended up with a collection of pumps that looked as varied as if I had asked for a complete mixture of every sort of pumps under the sun. The truth was that here were the companies Oase (they sent two!), Hozelock, Tetra, Heissner, Laguna and Blagdon, and these were their choice of pump for this particular job in hand. Expense to a certain extent is secondary consideration in this comparison, also funnily enough performance figures. As long as the pump produced more or less the figures on the side of the box in lab-style conditions, I wanted to see how they performed in the ‘wild’! 

Also I wanted to see how idiot-proof they were. Although I’ve creating water gardens for 23 years now and I feel I can spot a charlatan piece of kit at twenty paces, when it comes to putting together one of these completely alien pieces equipment, I feel like some ham fisted toddler with an Airfix kit completely beyond my age range. Once upon a time you got the basic pump and then you cobbled together you own mishmash of plumber’s fittings, jubilee clips and tubing at some vast extra expense. Now it all seems to be there in the box, all that you need to turn your submersible pump from a fountain to a waterfall pump or to even have both.

But how easy is it to put together and then take apart when necessary? And also how often is it necessary to take it apart? All important questions in the general running of things.

In general when it came to fittings there was more there than you could imagine ever using in any circumstances, and in one case I tested, the tools to dismantle the machine were included as well. There is no doubt the manufacturers are catering for all tastes, for instance, for those who like to have technology and control at their finger tips as top priorities, Oase do a TV style remote control as an add-on for their fountain pumps. So is it possible that we punters are being blinded from the important bit by all these ‘buttons and bells’? We will see in this tale of the ‘magnificent seven pumps’ and how they coped in my hands, an ordinary person fitting them into an ordinary pond. 

The site: 

A pond that has remained derelict for the last 4 years at Blagdon Water Gardens which I revived especially for the occasion- without cleaning it out.)

The mission

Pumping a fountain for as long as possible in a fountain pump pond from hell. A thick scum of duckweed hides a mire of leaf maulm and silt churned up by a large waterfall. These conditions would in a matter hours simulate the same stress a pump might be put under in over a week in a normal pool.

The Role call

Laguna 1500 Free Flow:

One of the new offerings from the Hagen stable. It comes with a three-year guarantee, so like all of these pumps it is built to last. Coming in with a maximum flow capability of 1450 litres per hour (319 gallons), it can deliver 840litres (185gallons) per hour to a 1metre head. The power consumption is a lowly 21watts. The design, of the squashed robot armadillo style pump cage, with its large surface area grill to sieve the water, gave it a look of the modern filter-pumps that handle murky water without problem, but the literature warned that it was only ‘designed for clean water’. 

The fountain jet fittings went together with satisfying clunks and clicks, and looked as though they would be easy to dismantle when necessary.) You could have a large fountain jet or a dome fountain (‘bell jet) on a telescopic pipe above a flow control that doubled to divert water to another outlet that could be a remote fountain. So like most of the other pumps, within reason this could go at any reasonable depth and extend up to the surface. Its dumpy shape and flat bottom would ensure that it remained stable and if the bottom wasn’t level the jet could be angle to cope with the camber.

There was a fancy pump cage backwash facility, which could be fitted up (on a semi-permanent basis) to a garden hose, so that when the pump hose clogged you could just blast it off the outside from a jet of water from the inside. But I weren’t havin’ no truck with no fancy shenanigans like that.

Oase Nautilus 80:

One of the pumps with ‘wings’. This was claimed to shift 16 litres a minute, which translates up to 960litres per hour. It was proportionately less daunted by a challenge than the Laguna, by being able to get 600litres per hour to 1metre, but with a price tag of a penny short of £80 you expect some surprises.

One of those surprises comes with those wings, which are filter grills for the water. Apart from increasing the surface area through which to draw water when they are lifted, they can in fact be detached from the main pump cage body and fitted to another panel with its own flow control and placed in a position where they can easily be maintained. By dint of an extension tube, water could then be drawn from some distance away from the pump. This would also help with circulating water in a pond.

The three fountain jet patterns or dome fountain attachment were supported on a telescopic tube, which has an integrated spotlight holder if you wanted to illuminate the fountain with Oase underwater spotlights. If this were the case, the pump would need to be well screwed down on its support since the main pump cage did not seem to be particularly stable especially with the fountain jet on full extension.

There was a “main flow regulator” and a “partial flow regulator”, both affecting the flow of the fountain, although the partial regulator could be used to control a separate outlet. A stepped hose-tail that could be sawn off to suit a variety of pipe sizes came with it.)

What with even a strainer inset into the fountain tube to prevent the jet from blocking, there seemed a really concerted effort to design a pump that would provide an effective and sustainable fountain here regardless of expense.) Remember when considering expense of this pump, balance that with a minute running cost arising from it 15watt power consumption and then there was a whopping 5 year guarantee.

Oase Aquarius 1200:

A more modest 3 year guarantee came with this slightly meatier cousin, providing a mean maximum through-put of 1200 litres, 720lph to 1 metre, no flapping wings but still the miniscule power consumption of 15watts. 

At £89.99p you may be you are desperately looking for the clever gizmos. This comes in the ingenious ‘universal joint’ that allows any combination of fountain or waterfall outlet to be operated at any angle and flow control for two outlets.) 

A stepped hose-tail, telescoping fountain tube and three fountain patterns are included in the package, but no dome jet. 

Heissner P750 Versailles:

This pump arrived late and I had second thoughts in including it in the trial since it seemed so much smaller than the others; a 10watt motor moving a maximum of 750litres per hour and only 200 litres to a 1 metre head. But what do expect for £32.

The actual motor size was not really a lot smaller. The other pumps gave the impression of being much larger because they were encased in a larger cage. The thinking being that the larger the surface area to draw in water, the less quickly will it clog. The P750 depended on not clogging by virtue of an open sponge in a much smaller cage over the intake to the pump; ‘ye olde fashioned methode’ but stylishly done.

It came with the telescopic jet stem, one little jet with tiny holes, or this could be replaced with a hose-tail fitting or dome jet.) It seemed oh-so-flimsy, but Heissner obviously had faith in it because it also comes with a 3year guarantee.

Tetra FPX3000:

Seemed a little big for this ballgame, 44 watts and 3000lph with up to a 4metre head, but I’m glad it came because it looked different; a lot of power for around £90. Possibly too much for a fountain in a small pool, but it was obviously a fountain pump because the whole design seemed orientated around the fountain stem. 

It had a distinct ‘boy’s toy’ feel with its sturdy extending jet stem and big sturdy fittings, further enhanced with the specialised tools for dismantling it.) It seemed to have the familiar grill/pump cage style of design around a small motor, but in fact there was also an open filter sponge in there to trap the detritus too. The flattened ball shape looked as though it would be more comfortable on its side, which if it was sentient, it had already made that decision.

Blagdon Hydratech 1500:

Another fairly powerful motor, it used 32watts to shift a maximum of 1550 litres or 900litres to 1 metre. Apart from the cage that seemed frail, belying its solid looking shape, this unit seemed as though it had been well thought out for the job in hand and so £59.99 seemed good value for money. 

It had a lot of sturdy looking fittings, along with the telescopic pipe and seemingly obligatory dome jet.) 

Hozelock Cascade:

At 18watts and 1000litres per hour, 500litres to 1 metre we have the middle-of-the-road at £56. Hozelock have over recent years have set the standard for others follow, but the others have had the advantage of being able ‘to come from behind’ by improving on the ingenuity of some of the Hozelock developments.

Sometimes the ‘improvement’ is for just a larger surfeit of fittings, and it seemed everybody had certainly gone one better than Hozelock in this bunch – there was no telescopic tube for the fountain jet, and here was a pump that really was only any good for a small fountain. It was just as well that I had a position near the water surface to try this one.)

Trial and Tribulation

Duly set up on level surfaces, the pumps were turned on all together. The Tetra immediately blew off the whole telescopic tube and jet fitting like the launch of an Apollo mission that failed in the ‘drink’.

I rescued the pipe and then ensured a tighter fit with PTFE plumbers tape. The second try was witness to the launch of fountain jet on its own and shortly after, the pump fell over and that is where it seemed to want to stay. Being quite substantial and made from a heavy plastic the fountain jet sank in the depths and despite much wasted effort it was never recovered. Anyway I stirred up the silt enough to make pumping fountains doubly difficult. )

From here on the fountains failed as quickly as it took me to get out of the pool and before I could take a photograph.

The Hozelock blew off the regulator or flow valve, which was easily found because it floated. After an initial blockage it settled down to a consistent if mediocre tick over. After a couple of hours it looked decidedly ragged again. There was a certain reluctance to attend to any jet blockage on this pump since it needed to be prized apart with a coin and as much strength as cold fingers could muster. 

The Laguna was next.

This was easy to get off but difficult to clean out and then the angle of the tube (or ‘riser’ in the parlance) did not seem to keen to be set in an upright position. The Nautilus was next to go in this fairly quick succession. The jet on the Nautilus was easy to remove, but that was clear. It was the internal strainer in the tube that was blocked. So I tried it without it with only temporary respite success –yep, the jet blocked then. A pump clogs up at the smallest orifices. The Nautilus strainer)

The Aquarius faired much the best jet-wise of the cage pumps, but when it did clog you had to remember there was a notch that located it into position. Its main problem was its instability, which was proving to be as annoying as the Tetra. Meanwhile this had no fountain jet to clog and so was merrily spraying away unfettered.

The Heissner, the Aquarius and the Tetra were the three best performers at this stage

The Blagdon Hydratech suffered a few blocked jet holes but the power was still there and it continued fairly unabated, albeit untidily.

The real star of this part of the show was the Heissner.

It just kept going with a fine delicate spray for the 4 hours I was messing around with the others, and just did not seem to reduce from the 1 metre high spray that it started with.

Stage Two

Since most of the pumps came with dome fountains or bell jets, I thought it only fair to compare them with these fitted, and in the case of the Aquarius and the Tetra without any jet at all. The fitting for the bell jet for the Tetra had departed into space with the fountain jet. At least this would indicate whether it was the intake of water or the jet clogging that was reducing the pump performance.

Fitting the bell jets or was a different story. The Blagdon Hydratech had by far the most impressive jet and seemed borne for the role it had now been allotted.

Over time the pumps with the sponge filters, the Heissner and to a lesser extent the Tetra, began to flag slightly. The pumps in cages seemed much happier for the long haul, apart from Nautilus, which was suffering from being inundated with Duckweed.

Bits and Pieces

Taking the pumps apart revealed all. It was immediately apparent that the pumps had been doing the jobs they had been designed to do. The cage grills and the sponges together had all been effective in keeping the impellor blades perfectly clear. With the caged style pumps, any debris that had got through was pushed through before it came entangled with the impellor and so had had got lodged in the fountain jets. 

There was quite a variety of design inside and as many different ways of taking the things apart.

  • The Tetra required a screwdriver as well as the tools they provided and so did the Laguna. The others came apart all too easily once you knew which buttons to press, and once they fell apart they were a bit of a puzzle trying to figure out how the pump fitted back in neatly. So take note of that.
  • The Hydratech had lots of small bits that could easily be lost ‘in the field’ and in fact they all had tiny little rubber bearings, so I would recommend serious maintenance and cleaning take place back at the ranch. The Nautilus, although first to succumb to the clogging, the impellor was still pristine.
  • The Heissner P750, the sponge began to clog at the end of the day.
  • The Tetra pre-filter sponge did its job, which was fortunate since it required some effort to get to the impellor.
  • Hozelock was the next caged pump to clog, but this may have been because it was so near the surface.
  • Oase Aqaurius seem content to carry on with slightly diminished flow.
  • The best performer with the dome/bell jet was the Blagdon Hydratech. I wondered if it was something to do with the impellor design.

Fountain pump trial review conclusions

These were all good pumps and all had enough redeeming features to make them good value for money. As long as you are aware of their drawbacks in certain situations you are half way to solving the problems that might arise.

When it comes to good pumps for fountains, you don’t necessarily get a better fountain for more money although you might get more buttons, fittings and features. 

To get the best out of the pump it must be used in the way the manufacturer recommend. So if it has a backwash facility like the Laguna, use it and if it has a remote filtration facility like the Nautilus, at least try it. Fountains by their nature seem to be maintenance intensive and anything that makes this easier to do is worth trying. 

If you want a florid fountain spray, then a sponge filter is more effective against the detritus blocking the jet, but if it is a bit mucky as ponds tend to be, go for a very open jetted fountain like the bell jet and use the cage style. It will remain maintenance free for longer. 

One last thing: rehearse taking the thing apart and putting it back together before you have to do it in the cold and damp and the murk and mire. This will also give you some warning notion of what goes together too easily come apart even more easily and (Sod’s Law) in the worst possible circumstances.

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