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Garden water features, fountains , ponds, pumps, filtration systems, garden lights etc. are just some of the topics covered here.

Below, we have tried to answer the most common questions visitors to this our Web site may have. If you find that your question is not answered on this page, please E-mail us or call us at (045) 870 970.

Don't forget to check out our How to section for lots more useful advice.

Where are you located? We are in located Allenwood, Co. Kildare, Ireland. We deliver throughout Ireland

Where can I get a copy of Oase manual and brochures?

Instructions for use and safety data sheets for your Oase products for download are available here 

Do you install water features? Yes, RockWorld offers a complete service including design, delivery and installation. We also have a number of features that are very easy to install yourself and will fit in the boot of your car. You will also find a number of professional landscapers who are familiar with many general aspects of water feature installation and we are always available to give guidance if required.

What price are your water features  Prices are very reasonable. We aim to have fountains and water features in all price ranges. All prices are shown on our website to help you make the best choice and comparison.


Why choose Rockworld?
Rockworld has both the design capabilities to produce water features, fountains, ponds and anything related to aquascapes that look impressive but also have key engineering capabilities that make the feature work at its best. We have been in business since 1999 and can offer a wealth of experience on all aspects of water features and water displays for both residential and commercial clients. As we specialise in water features you can be sure of having your project completed to the highest standards. We are also Ireland's first authorised Oase installer as well as a certified Oase Gold Retailer.

Do I need a water supply for my water feature? No, the water is re-circulated using a submersible pump. You do need an electricity supply to power the pump and lights. We can size the exact pump you require so that you get the exact effect you wish while using the minimum of electricity. Our range of pumps are Eco friendly and have the highest output flow rate for the minimum electricity usage.

How often do I need to top up the water reservoir? On average once a month but in warmer weather water will evaporate faster and require more frequent top ups.  Simply use a hose pipe to top up your reservoir. An alternative is to plumb a water supply out to the feature and add a ball cock, then you never have to worry about it again.
For commercial water features we recommend our electronic level sensor kit for optimal performance. These kits do not react to waving in ponds which can be a cause of unwanted filling in ballcock type systems. 

What are the electrical requirements? You will need one circuit for the pump and if required a separate circuit for lighting and filtration. We recommend that you use a qualified electrician. All outside wiring should be protected by a dedicated rcd (residual current detector sometimes called elcb)
All pumps come with 10 metres (33 feet) of cable attached.

Do you recommend lights be added to my water feature? Yes, adding low voltage lights to a water feature is well worth it. It means that the water feature can be enjoyed at night time as well as during the day. The way moving water catches light is fantastic. All our lights  are submersible , with some you can change the colour of the lens, some are LED and  others you can change colour with a remote control. They come complete with low voltage outdoor transformers and some with submersible transformers.

I want a tall natural rock water feature; can you supply this? Yes, we can supply this. It’s important to note that when choosing the height and shape of a natural rock water feature the aim is to recirculate the water between the rock and the reservoir. We want to avoid the water from the rock splashing outside the reservoir, hence we try and size the rock according to the space you have available for a reservoir. As a very rough rule of thumb the reservoir diameter should be at least equal to the height of the rock. Therefore a typical 1 meter high (3 feet) rock water feature will need a 1 meter diameter reservoir

Where type of rocks do you supply? Granite, Sandstone, Limestone, Schist Lava rock, Marble.

Do you supply all the equipment for water features? We supply all that is required as well as extras such as lighting and spare parts. Simply browse our website, use the search facility at the top of page or give us a call and we'll be happy to help.

What sizes are the water features you supply? As our range of water features is extremely comprehensive we have a vast array of sizes.

How does ultra violet clarification work? Ultra violet clarification (UV) clears water which contains algae thus keeping your pond or stream water clear and clean. Many water utilities use UV to provide greater protection from disease causing bacteria in drinking water. A photochemical effect is created using UV light and vital processes are stopped within the micro organism cells, therefore making the micro organisms harmless. The UV light inactivates the micro organisms by penetrating cell membranes to disrupt DNA molecules and prevent cell replication. This process is often referred to as flocculation. With our UV clarifiers water flows through an irradiation chamber. Importantly a UV must be sized to suit the volume of water flowing through it and the UV bulbs must be replaced once a year. In order to size the correct UV you need to know the volume of your water feature (we'll calculate for you if you need)

Do you supply stainless steel water features and water walls? Yes, spheres, waterwalls to name but a few.

How much do the rocks weigh? They are heavy! Figure approximately 150 pounds per cubic foot or 2400 kilograms per cubic metre. So a rock approximately 3 feet square weighs nearly 2 and a half tons. Don’t worry though as we can arrange delivery and installation if required. We also supply a range of specially designed water reservoirs designed to support the weight of rocks.

I am not sure about my measurements; can you help? Whilst many of us use both metric and imperial measurements we find that for accuracy metric is easier. Just call us if you need more help and we will do the conversions. (a quick way of converting feet to metres is multiply feet by 0.305, eg 5 feet =5 x 0.305 = 1.525 metres)

I want a fish pond. What are the most important facts?

Size, shape, plants, fish, location are starting points. The bigger the better, the deeper the better.

A rule of thumb for fish stock levels: Insert a maximum of 1 kg fish per cubic meter with a minimum depth of 1 m. However, many fish will live quite happily in 400mm of water. If you have constructed your pond in autumn, you should wait to introduce fish to your pond until spring. This way the pond and the fish do not have to cope with the difficulties of winter immediately. Don't forget to add a hide out for your fish.

How do I decide which pump I need? 
Fountain pump or waterfall/filtration pump is first decision. To keep water clean you'll need a waterfall/filtration pump , to run a fountain you'll need a fountain pump. Main visual difference between the fountain pumps and filtration pumps is the size of particles they let in. (technically they also have different impeller design ). Fountain pumps have small holes in their inlet cage so as not to block nozzle whereas watercourse and filtration pumps have much larger holes in their inlet cage so they can pass them though.
We will be glad to help you decide which pump you require.

As a rule of thumb when it comes to water features there are 2 different types of pumps, one for fountains and one for water courses like streams, waterfalls and filtration.

For water features we need to know how high the water must go and the width the water flows out or over.

For ponds we need to know the volume of water in it (Length x Width x Depth), whether or not you have fish and if so are the fish koi.

Flow requirements for ponds.
A typical goldfish pond should aim to recirculate the water over once every two hours whilst in a heavily stocked koi pond the water should be recirculated every hour. For example let's say we have a pond size 4m by 3m wide and 1m deep (13’x10’x3’) then them maximum pond volume ( if rectangular with no shelves) = 4 x 3 x 1,000 = 12,000 Litres (2643 gallons). So a 6,000 litre per hour pump is required for goldfish (such as Aquamax Eco Premium 6,000) or a 12,000 litre per hour pump (Aquamax Eco Premium 12,000) is required for koi.
Pumping water above the surface of the pond causes the pump reduce its output flow rate the higher it goes (head loss). Typically a pump may be required to power a waterfall of 1m high (3 feet 4 inches) so using the example of a 12,000 litre fish pond with a 1m height required then a suitable upgrade would be the Aquamax Eco Premium 8000 which produces 6000lph at 1m.
To help you with these calculations we provide graphs which show the pump output flow rate at different heights or simply give us a call and we will work it out for you.

I’m building a stream/waterfall; how do I decide which pump I need? Firstly, you need a watercourse/filtration pump not a fountain pump. Then you need some measurements. The height of stream above pond and the width of steam.
To choose a pump for a stream we are interested in flow rate of the pump. We have to choose a pump capable of outputting about 1.5 to 2 litres of water per minute for every cm width of the stream at the maximum height of the stream allowing for friction losses in the pipe. So a 30cm wide stream at 2m high will require a pump capable of outputting 60 litres per minute at 2m high. So we then look at the pump graphs to find the correct pump. Do not worry, once you have some measurements (WIDTH OF STREAM & MAXIMUM HEIGHT OF STREAM/WATERFALL) we can size an appropriate pump for your needs.

What other benefits is there to having a water feature? Besides the great visual value of our water features, they provide additional benefits such as sound. The sound has a calming relaxing stress less effect as the water falls gently down the face of the feature.
The sound of moving water can also provide some privacy in an open lobby/reception area or with nearby gardens and balconies. Sound is also of great benefit to anyone with a sight deficiency as it acts as guide. Naturally the sound can be adjusted to suit via a valve on the pump.
Additional benefits are airborne particles are attracted to the running water of the feature which in return cleans the air developing a cleaner environment as each day passes.


I have/want a pond. What can you do to make it child safe? Rockworld can supply customised safety grid OR why not get a water feature without a pond, a pondless water feature. Check out our reservoirs and you will see many have lids which prevent access to the water below.

I’d like to create my own pond but I’m not sure where to start. What are the basics of designing one? First you should have a basic scaled sketch of your garden. Include pathways, house outline, sheds, trees and such like. Then choose a proposed location for your pond. When deciding on a location it is a good idea to consider how you will view the pond, for instance can it be seen from the main living area of your home or is it close to a seating area. Aim to have a pond of at least 4000 litres and one meter deep. So a pond 2 meters long and 2 meters wide and one meter deep holds 4000 litres.{2x2x1=4 cubic meters = 4000 litres}. Take your drawing with you when seeking advice and we will be able to fine tune your design with your proposed plans. If there are any underground services present don’t forget to add these to your sketch. 

Our garden is average sized and we are trying to decide on a formal or informal pond shape, which is best, what advice can you offer? The main point is scale, the water feature should be sized to fit into your garden. Formal ponds can be very good for small gardens due to their distinguishing clean shapes (squares, oblongs, circles or semicircles). An informal pond (curves or kidney shapes) is designed to look more natural. It should blend in with its surroundings and is usually planted to link your garden, water and marginal plants together. It comes down to what you prefer

Which is better a raised pond or a sunken pond? Both options have merits and pitfalls. Above ground ponds can be harder to build but easier to maintain. Raised ponds can be safer as it is harder to fall in but they can be more exposed to temperature fluctuations which can effect fish health. They can also be difficult to hide filtration equipment. There are ways around the issues, for instance building partly below ground and partly above helps to maintain temperature changes. Similarly, "in pond" filters are very easy to use in this case, as are pressure filters.

I love my water feature during the day and I am very proud of what I have achieved. The one thing that could be improved upon would be effective night time lighting. Have you any suggestions? You are right to consider making the most of your water feature in the evening. One of the great pleasures of water features is to be able to relax on a warm evening with the sound and sight of moving water. If your water feature is positioned such that you can see if from your house, adding lights will make a dramatic improvement on the amount of enjoyment you get from it. Underwater lights are used to create a subtle effect with dramatic shadowing. Lights with different lens colour also create wonderful effects. Lighting from below your water feature with two spotlights placed apart often works best as it creates the most interesting shadows and effects as the water moves. What we want to do is enhance the feature in a subtle manner rather than floodlighting a mass area. Low energy led lighting and colour changing lights are a great choice.

I have a small balcony and no garden, I’d love a water feature but is it possible? Water features can be placed anywhere, as they don’t require a permanent water supply. Any space can be transformed into a tranquil oasis with the aid of trickling water. Wall water features work particularly well on balconies as they take up so little space.

Location, location. I’d love a water feature but am not sure where to locate it. Try to locate your water feature where you are able to see it from your main window or patio and remember you will need a power source. The availability of many different pond devices means we can now place a pond anywhere you choose. Technology has moved so much that there are hardly any location limitations now.
A pond in direct sunlight all day, that is also shallow will require a larger filtration system than a pond that is deeper and partly shaded, even if the volume of water in each is equal.

How do you pronounce Oase? Oase is a German word meaning oasis or haven.
Its pronounced “oh ahh zay”, but don’t worry we will know what you are talking about, we have heard several variations.

Do you offer gift vouchers? Yes we are pleased to accept payment for gift vouchers. 

What is the volume of water in my pond?
Quick answer is usually in the range of 1000 litres to 30,000 litres for average ponds but that's like answering how long is a piece of string.  We can make a good estimate knowing length, width and depth.

Volume is the amount of three dimensional space occupied by an object. For our purposes we deal with water and the most common question relating to volume is what is the volume of my water feature.

Firstly, we need too know what type of shape we are dealing with, is it a square pond, a rectangular pond, a circular pond or an uneven shape such as a kidney type shape. Then we need to know its measurements, such as length, width, depth if square or radius.

Let's start with the volume of cube shapes like square or rectangular ponds. The volume a cube or cuboid is the length multiplied by the width multiplied by the depth often described as L x W x H

Its best to stick to metric system using meters as it makes measurements much simpler. For example, a pond 2 meters long, 4 meters wide and 0.5 meters depth has a volume of 2 x 4 x 0.5 = 4 cubic meters = 4000 litres of water.

As one cubic meter has a volume of 1000 litres, then 4 cubic meters has a volume of 4 x 1000 = 4000 litres

Interestingly (or not) one cubic meter of water weighs one thousand kilos so we also know the weight of water in the above example is 4000 kilograms.

So one litre of water weighs one kilogram.

With the above in mind we can simply calculate the volume of any cube shape.

We basically just get the area (length by width) and then multiply by the depth (height) to calculate the volume.

Here is another example.

My rectangular pond is 2.5 meters wide, 6 meters long and 1 meter deep. Which filter do I need?

Firstly we get the volume being 2.5 x 6 x 1 =15 cubic meter

Then we translate this into litres by multiplying by 1000 so 15 x 1000 =15,000 litres of water.

Now we know the volume of the pond we can calculate the filter requirement. Unfortunately, we need to ask a few more questions to work out the correctly sized filter but nothing to strenuous. Basic question is "are there fish in the pond and if so are the Koi or goldfish?". The reason is we fish create waste and some more than others so to size your filter we need to have an idea of the pond fish type. At its very simplest a filter designed for 10,000 litres of water is generally designed for a pond with no fish and just a few plants, that same filter may only be suitable for a pond of 5000 litres with goldfish and 2500 with Koi. If the filter is undersized it will not be capable of cleaning the pond and providing clear water to view your fish. Don’t worry though as we have several types of filters and many can be simply upgraded to provide more cleaning potential.

Getting back to Volume, let's say we have a cylinder shape, i.e.. a round pond. The volume is 3.124 multiplied by the radius squared. (The radius of a circle is the distance from the side to the center). For example a pond 2 meters diameter and 1 meter deep has a volume of 3.142 multiplied by 2 multiplied by 2 multiplied by 1 (3.142 x 2 x 2 x1) = 12.568 cubic meters = 12,568 litres.

Wondering where the 3.142 came into play, well that’s 22/7 or pie. Pie is the ratio of a circle's circumference to its diameter in Euclidean geometry, and has many uses in mathematics, physics, and engineering. That’s why we call this section Jargon. It's extremely useful information but we are happy to make the calculations for you. Even if you prefer the old feet and inches (known as the imperial system, and still widely used in the UK and USA) we will convert it for you and make all the right calculations to size your water feature correctly.

We will deal more with irregular shapes in the future but as a rough guide the volume of a kidney shaped pond with sloping sides is calculated by imaging it as a rectangular shape, calculating the volume for this then subtracting one third. You could also just fill your pond with a hose and time how long it takes to fill. If you know it takes say 40 minutes to fill a pond and the same hose fills a 10 litre bucket in one minute, then your pond is the same as 40 ten litre buckets or 40x10 =400 litres.

I have heard that some plants are not suitable for ponds, which plants are not suitable.? The following plants have been banned because they are invasive, i.e. they attack native habitat. These plants can cause serious and permanent problems to our ecosystem. They can be bigger and faster growing than native species. As a result, native species are unable to compete and non-native species take over. These plants can often alter local ecology and physically clog waterways and reduce fish population. Please avoid the following:

The five plants banned from sale by DEFRA in the UK are:
Water fern (Azolla filiculoides)
Parrot’s feather (Myriophyllum aquaticum)
Floating pennywort (Hydrocotyle ranunculoides)
Australian swamp stone crop/New Zealand pygmyweed (Crassula helmsii)
Water primrose (Ludwigia grandiflora)

I've purchased an Oase product which has an extended guarantee, how do I apply for this extended guarantee?
Many Oase products have the option to extend the manufacturers guarantee by up to 2 years. You can either fill in the guarantee form that came with your Oase product or fill out an online form via the Oase website

What is the guarantee for Pontec Products?

PFG GmbH guarantees this PFG device that you have purchased for a period of 24 months in accordance with the conditions listed below. The guarantee exists in addition to the statutory warranty obligations of the seller and does not affect these statutory warranty obligations. The guarantee applies without prejudice to mandatory statutory liability provisions, for example the provisions of the Product Liability Act, in cases of intent and gross negligence, injury to life, limb or health on the part of PFG GmbH or its vicarious agents. Guarantee period The guarantee period begins on the date of first purchase of the PFG device from the PFG stockist. The guarantee period will not be extended or renewed in the event of a guarantee claim or if the PFG device is resold. Guarantee PFG GmbH guarantees proper functionality and usability of the PFG device in accordance with its intended purpose. In this regard, the state of science and technology at the time of production shall be authoritative. The PFG device must have already shown the defect that caused the damage at this point in time. In the event of a guarantee claim, PFG GmbH reserves the right to repair the PFG device free of charge or to deliver spare parts for the PFG device or a replacement device free of charge. If the device type of the PFG device in question is no longer being manufactured, PFG GmbH reserves the right to deliver a replacement device of its own choice from the PFG product range that most nearly approaches the device type that is the object of the complaint. The guarantee applies only to damage on the purchased PFG device itself. Reimbursement of expenses for installation, removal and inspection, compensation claims for damage that did not occur on the purchased article itself, as well as claims for loss of profit or loss of use and further claims for damages and losses of any kind whatsoever caused by the PFG device or its use, are excluded from the guarantee. Guarantee exclusion Excluded from the guarantee are damages caused by mechanical damage due to accident, fall or impact, or force majeure or natural disasters, in particular, but not limited to, floods, fires or frost damage, negligent or wilful destruction (e.g. by cutting off the plug or shortening the power cable), or misuse, improper or non-intended use, installation and operator errors or lack of care (e.g. use of unsuitable cleaning agents, omitted maintenance, lime-scale deposits), overload or failure to comply with the user instructions, the user‘s own repair efforts, as well as damages to wear parts such as illuminant and rotors, fragile parts, such as glass, light bulbs and consumables, such as batteries or filter foams. With regard to proper use, PFG GmbH refers to the operating instructions, which are a component of this guarantee. Assertion of claims Guarantee claims can only be asserted against PFG GmbH, Tecklenburger Straße 161, 48477 Hörstel, Germany, within the guarantee period. To do this, the person submitting the claim, bearing the shipping costs and the transport risk, sends the device, or the part of the device, that is the object of the complaint, to PFG GmbH together with a copy of the original sales receipt issued by the PFG stockist, this guarantee certificate and written information concerning the defect that is the object of the complaint. General provisions This guarantee is governed by German law with exclusion of the United Nations Convention on Contracts for the International Sale of Goods (CISG). PfG GmbH Postfach 2068 48469 Hörstel

Tell me about testing water?

The following parameter's are considered when analysing water.

Ph Value

The pH value is probably the most important and meaningful value that provides information about the quality of the water. It indicates whether the water is acidic or alkaline and whether there are good living conditions for fish and plants. We recommend pH values of between 7.5 and 8.5, as pH values outside of this range are unfavourable for organisms and should be avoided.


The conductivity of water reflects its salinity. Conductivity is measured in µs/cm (microsiemens per cm). Fresh water or pond water should have a conductivity of between 300 and 1200 µS/cm. If the conductivity is lower, even the most minor of influences may result in the water reacting with a significant change in the pH value, for example. Water begins to be considered as salt water from a conductivity value of greater than 1200 µS/cm.

Carbonate Hardness

The concentration of calcium hydrogen carbonate present in a body of water is of crucial importance for the pH value to remain stable. The carbonate hardness, also known as temporary hardness, is the measure of this concentration. A sufficiently high carbonate hardness in a body of water can stabilise the pH value of the water and successfully counteract a variation in the pH value. As with the total hardness, the carbonate hardness of a body of water is given in °d.H. or mmol/l and should be between 5 and 12°d.H. in natural fresh water.

Total Hardness

In addition to dissolved gases, water also contains dissolved minerals (ions). The magnesium and calcium ions dissolved in the water play an important role — these are also referred to as hardness formers. The concentrations of magnesium and calcium ions dissolved in the water constitute the total hardness of the water. This is the sum of permanent and temporary hardness. The hardness of water is specified in the unit °d.H. or alternatively in mmol/l. Natural bodies of fresh water have a total hardness of between 5° and 20°d.H.


Nitrite is a nitrogen compound that can enter pond water by way of contaminated drains, rainwater or food residues. There should be no nitrite present in an intact pond ecosystem. Concentrations of nitrite as low as 0.2 mg/l can have very harmful effects in a pond in the long term and may poison fish stocks. Nitrite accumulates in the blood of fish and prevents oxygen uptake. The fish show signs of asphyxiation. The nitrite also interacts with the pH value: the lower the pH value, the more toxic the nitrite that is present.


Like nitrite, ammonium is a nitrogen compound that can enter the pond from the microbiological degradation of fish excrement, through fertilisers or even through surface water. The pH value is an important parameter to determine how toxic the ammonium content is for aquatic organisms. At high pH values, the harmless ammonium transforms into toxic ammonia.​​​​​​​


Like ammonium and nitrite, nitrate is a nitrogen compound that is dissolved in water. It is produced as an end product of the microbial degradation of nitrite or enters the water through surface water as a result of heavy anthropogenic use. Higher quantities of nitrate cause excessive algae growth.​​​​​​​


Phosphate is the main nutrient for algae. Even the slightest increase in phosphate to more than 0.035 mg/l can trigger excessive algae growth. Phosphates are introduced to the water by fish feed or by adding water that is rich with phosphate. The phosphates are absorbed by the algae, which is why no phosphates can be detected in the water despite excessive algae growth. The issue with this is that phosphates are released back into the water when the algae dies off, which can then cause new algae growth.​​​​​​​

​​​​​​​I want to build a pondless water feature so I just see the flowing water of my stream and cascades but don't want a pond of open water.