Frequently Asked Questions

General FAQs

Q How deep should my pond be?







Q How do I build a pond?






Q How can I tell if my UV light is working?







Q Can your products be left outdoors for Winter?










Q What size of pump should I have for my pond?


A question we are often asked by our customers. The answer should be as easy as "the biggest you can afford."

However this makes the assumption that you have a knowledge of pumps and ponds with the potential for a large fund resource.

Sadly in reality this is not the case.

So the easiest way, is to calculate the pond volume size (See answers to our earlier questions) and use the volume calculation to give you the volume of water that  you have in your pond. Once you have the volume of water, whether in gallons or litres, you can simply use this figure to gauge the size of the pump you require to circulate the volume of water.

The normal standard criteria is to circulate the pond water volume once every two hours.

So if you have 500 (litres or gallons) of water in your pond, then you need a pump that can circulate 250 (Litre or gallons) per hour.

This would meet the minumum criteria of circulating the pond water, once every two hours.

(Laguna suggest that you select the next pump up in range, to allow for future / additional growth capacity of the pond)


NB:- A few points to note:-

This does not take into consideration head heights, water blade fountains, filters,spitters or tubing/piping that may be installed.

Please see our selection of FAQs on these calculation.

Some manufacturers will cite a higher pond volume capacities by changing the figure  of once every two hours,(the standard figure used) to once every three or four hours. Ensure you do not get caught out!


Q How much water does my pond hold?


The easiest way to find out how much water your pond holds is to buy a Water Counter (Litre/Gallon) Meter Adaptor. This fits onto the end of your water hose and counts the units of water that it takes to fill up the pond.

This is the most accurate way of KNOWING your maximum water volume. 

This is the best information you can have for the maximum level and volume of your pond. All other methods are best guess.

NB:- it will only remian valid if the water is at the same full mark on your pond when you filled it! Otherwise you will have to take into consideration evaporation. See other FAQs for explanation.

Q How do I calculate the litre volume of water in my Pond ?



The volume of water in any pond will be determined by the size and shape of the pond.

Squares, rectangular and circular shapes are very easy to calculate by using standard volume calculations.


Squares or rectangular Pond Volume Metric = Length (m) x Width (m) x Depth (m) = volume in cubic metres.

(1 cubic metre =1,000 Litres)

so Length ? (m) x Width ? (m) x Depth (m) x 1000 = volume in litres.


Round Pond Volume Metric = Radius x Radius x 3.142 x Depth = Volume in cubic metres.

(1 cubic metre =1,000 Litres)

Q How do I calculate the Imperial gallons of my pond


Square/Rectangular Pond Volume Imperial

Length x width x depth = volume in cubic feet.


so Length width x depth x 6.23 = Volume in Imperial gallons


Round pond Volume Imperial






Q What do I need to consider before buying my pump?



The things you need to consider before buying a pump are:-

  1. Do you wish to run the pump 24/7, 365 days a year? (See running a pump and pump wattages FAQs)
  2. What volume of water it needs to circulate? (See, How do I calculate the volume of water in my pond? FAQ questions)
  3. Do you want to provide for a waterfall?  (See, How do I calculate the volume of water required for my waterfall? FAQ questions)
  4. Do you want to provide for a fountain?   (See, How do I calculate the volume of water required for my fountain? FAQ questions)
  5. Do you wish to provide for a filter box?   (See, How do I calculate the volume of water required for my filterbox? FAQ questions)
  6. How much head height does it have to cope with?   (See, How do I calculate the head height for my pump? FAQ questions)
  7. How much hose is needed for the above pond set up?  (See, How do I calculate the required hose amount? FAQ questions)
  8. How many fish do you wish to keep in the pond? 
  9. How often and how much food is to be used for the fish?
  10. How often do you wish to do maintenance?

Once these factors have been considered, you have the basic requirements for your pond pump



Q How do I calculate a pump size for my waterfall?


There needs to be several calculations made to get the desired result from any pump, that is running a waterfall.

  1. The head height required.
  2. The amount and size diameter of the hose used.
  3. The size of water spread required for the waterfall.

The head height required

 Is the distance from the pond surface to the top of the waterfall. This distance needs to be as accurate as possible. As the pump will need to be able to push the water up to this height.

The amount of hose used

The length of hose/piping used to connect the pump to the waterfall. For every 3m of hose/piping connected, you will need to add 30cm of head height to the pump requirement.

The type and diameter of hose/piping used will provide physical parameters that will govern the maximum water flowthrough rate. Every bend put into the installation will reduce waterflow rates by upto 30%.(If the installation is under 1m and no bends then most of these hose/piping impacts can be ignored.) 

The size of water spread required for the waterfall. 

For every 2.5cm/1" width of waterfall flow required for the waterfall, 250-350 LPH will be required to be dimensioned onto the pump LPH capacity.

Q What things do I need to consider for my fountian?


When buying a pump to create a fountain in your pond you need to consider the following:-

  1. Do you want a fountain/circulation pump only or will it also be required to run a filterbox or waterfall. (See Waterfall or Filterbox dimensioning FAQs)
  2. The depth of the pond and the height you would like the fountain to be. 
  3. What kind of fountain shape you would like.

 Is the pump for fountain use only or will it also be required to circulate the pond water to a filter box.

Calculate the water volume of your pond or water feature container. (See Calculating pond water volume FAQs.)

Pumps that are required to run waterfalls or filterboxes will need additional pump capacity to facilitate their proper use. See respective FAQs

The depth of the pond (where the pump will sit) and the height of the fountain required will add to the head height requirement of the pump.

The fountain shape or spray can be varied in design. There are crown, tulip, bell and rose shaped fountain heads available from pond pump manufacturers.Ensure your requirement is selected.

Q What do I need to think about for my hose or piping dimensioning?


When using flexible hosing or rigid piping there are some things that need to be taken into consideration.

Keep runs of hose/piping to a minimum. You will add 30cm of head height requirement on the pump for every 3m of hose/piping.

Try not to put too many bends or curves in the hose/piping, each bend can reduce water flow rates by up to 30%.

Most pumps have a dovetail facility which allow you to chose a varied diameter of hosing/piping.

Different diameters of hose/piping allow for a variety of maximum flow rates to be achieved.

1/4",1/2", 3/4",1",11/2" and 2" being standard hose/piping sizes. 

The smaller the diameter the smaller volume of water capable of being passed through it. However the smaller diameter can support a high pressure level.

Always try to budget for a diameter as large as possible for the water volume required, provisioning at least one model pump size larger than required. This will prevent you having to relay the hose/pipe work as you grow the fish volume of your pond.

If adding a splitter into the hose/piping, a flowrate reduction of up to 30% capacity can be expected. 





Q What do I need to consider when installing a filter box.


Things to consider,

Calculating the volume of water the pond holds. (See FAQs on calculating pond water volume)

The number of fish your pond will hold. (See FAQs on fish loading of ponds)

The number of fish you wish to keep in your pond

The above two points are referred to, as the pond bioload. This will determine how much water needs to be circulated and how much water needs to be fed to the filterbox.