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  Product Evaluation and testing ..........Air Pumps......... Please scroll down this page.

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We at COASTAL KOI consider product evaluation very important within our overall sales strategy, with a policy of only offering for sale items that we consider suitable for the purpose and to the best of our ability correctly described.

By carrying out our own in house evaluations on most products we sell and applying a high percentage quality control system of checking, we try to meet the needs of our customers.

When dealing with Top quality products by leading manufacturers : The names Aquamax Sequence Nexus Etc. spring to mind, the need for quality checks and evaluation is not quite so important. We tend to concentrate our in house evaluations on the lesser well known budget priced imported items.

Please find below the results of some of our findings:- 1*2*3*4*5* Higher the star rating the better.

Unless otherwise stated all electrical items are 220-240 Volts

Recent Trials and Evaluations

1). Super silent range from Hailea manufacturers statement not ours.

We are often asked the question how noisy Which is almost impossible to answer.

NOISE LEVELS All air pumps will make a noise, some more than others.

For smaller pumps we have found by placing on a carpeted floor behind a Sofa or similar can work very well Be sure to use a non return when pump is sited at a level lower level than the water in the tank.


During recent trials and evaluations of these air pumps we have used 10 mtrs of standard 4mm air-line from pump to air stone /s. and surprised ourselves a little in discovering only a very small reduction in performance.

This means that even the smaller pumps can be sited quite a distance away. (Peace and Quiet at last !!!!)

Outside use on small ponds These small pumps are not waterproof and will require to be installed in a dry weather proof well ventilated enclosure.

The ACO-22 series

Noise levels..... *** average

Reliability...... ****

Value for money.. *****

The ACO-62 series

Noise levels..... ****
Better than above especially the single outlet ACO-9601

Reliability...... ****

Value for money.. ****

The ACO-55 series

Noise levels..... ***** Best

Reliability...... ****

Value for money.. ****

Unless otherwise stated all electrical items are 220-240 Volts

The ACO-5503 and the ACO-5505 immediately above turned in the best overall performance, and are highly recommended.

The picture to the left shows the smaller of the two the 5503 Model powering a 40mm ball and a 50x25mm small can plus a 4" Ceramic Disc and a curtain in the background. all at a depth of about 12"

The pump was connected via 2 x Non Return valves and a valved manifold, the latter being neccessary because of the vastly differing back pressures of the different dispersion Stones / Disc etc.

WHAT SMALL PUMP DO I REQUIRE A question often asked, and not easily answered without the full facts being known.

Generally where normal straight forward Aquariums or Tanks are concerned it is the depth of the water that is probably the most important factor. Also of course the volume of water and what it is being used for eg. fish fresh or marine Qnty, size, and /or type.

Another important aspect that could be considered is : A small pump working into a 4" or maybe a 5" Ceramic disc would transfer considerably more oxygen into the water than the same pump and one or two small Air stones.

The output pressure of small aquarium air pumps will vary from approx .012 MPa (1.75psi) up to about .025 MPa (2.75psi). The volume of air output will also vary.

So to conclude we have at one end a single outlet air pump 0.012 MPa delivering 3.2 ltrs/in At the other end a double outlet one running at 0.025 MPa delivering 5.5 ltrs / min. and These in turn will run a fairly small Aquarium / Tank say 35 ltrs or so up to a fairly large one say 250 ltrs.

SPECIFICATIONS. PRESSURE :: Ltrs/min For individual pumps goto >>>>> Aquarium products

Please Note When referencing air pump specs generally the pressure will dictate the depth the dispersion tool can be operated at. Whereas the volume lts/min or ltrs/hr is the amount of air at zero head (No back pressure) pump with nothing attatched.

WHAT ELSE DO I REQUIRE Another question often asked,
To infuse the air into the water you will require some 4mm ID air line an Air stone/s or and /or Disc/s plus if the pump is installed at a level below that of the top of the tank, a Non Return will also be required one for every outlet. This will prevent water back siphoning to the pump. When two or more stones or discs with differing back pressures are employed they will require balancing.

Please follow links below for more info.

One (1) cubic ft of water = 6 gls (Gallons) which = approx 28 ltrs (Litres)

More information including the use of Non Returns goto >>>>> Air Pumps

More information Hailea spares goto >>>>> Hailea Air Pump spares

For more information plus specifications. goto >>>>> Aquarium products

Unless otherwise stated all electrical items are 220-240 Volts

2). Super silent V-20 from Hailea

An excellent small air pump well suited for the smaller pond or Quarantine tank.

Noise levels..... ***** Extremely quiet
Reliability......... *****
Value for money.. *****


3). Super silent ACO-97 Series range from Hailea

Quite superb budget priced Pond air pumps very Low in noise with decent power levels.

Noise levels..... ***** Extremely quiet

Reliability...... *****

Value for money.. *****

We have used these pumps ourselves for the past 3 years and rate them without doubt the very best budget priced Air pumps available anywhere.

For more information on the above please goto >>>>> Hailea Diaphragm


4). Hi-Blow HAP range from Hailea

Genuine Hiblow pumps at very reasonable prices. We evaluated and tested these pumps using the Airtec as a bench mark. Overall the performance was excellent with plenty of power for use in deep water. Noise levels were slightly higher than the equivalent Airtec but not excessively so.

In conclusion (noise levels):- They would be audible in a quiet room or area with a relative low ambient background noise.

Noise levels..... **** reasonable (Slightly noisier than the Airtec)

Reliability...... ****

Value for money.. *****

Special note 1. We are often asked why there is often a huge diffence in actual performance between pumps when similar outputs Ltrs / min specifications are quoted.

To answer this we have to accept that manufacturers will use there own interprtation and slant on how they state their specifications.

To explain this I will use an example: >> Hailea 45 ltr piston air pump >> This figure is accurate in as much that it does not take into account any applied back pressure. Not even the manifold let alone any pumping depth. Where as most of the quality Air pump manufacturers will often factor the pressure drop that might be encoutered in your average system.

RULE OF THUMB Unless otherwise stated. If you look at two similar Ltr/min Air pumps one costing twice as much as the other. The most expensive is normally going to be the better and return better peformance at depth When back pressure is applied.


5). Hailea Piston operated Air Pumps

Love or Hate these Budget Piston air pumps from Hailea. One thing is for sure they are ultra reliable.

During extensive evaluation and testing outside in all weathers,these piston pumps have, apart from some slight rusting on the plated areas proved 100% reliable.

PUMPING DEPTHS :: Is a difficult area to assess as it will vary depending on type and number of dispersion tools (Stones / Discs /Diffusers. Figures below are general guidance only.

45ltr ACO-208 .... (600mm - 775mm)........24" - 30"
55ltr ACO-308 .... (775mm - 900mm)........30" - 36"
70ltr ACO-318 .... (900mm - 1000mm)......36" - 39"
90ltr ACO-388 .... (1275mm - 1500mm)....50" - 60"
250ltr ACO-380 ...(1500mm - 2500mm)....60" - 100"

More information including the use of NON RETURNS goto >>>>> Air Pumps

For prices and more information on the above please goto >>>> Piston Air Pumps

Please note Even with the above findings we still recommend the following procedure for installation.

Manufacturers recommendations are to install away from high temperatures, direct sunshine, damp or dusty conditions.

Our own recommendations For outside would be to recommend installing in a well ventilated enclosure keeping the pump dry and keeping the worst of the weather at bay, also above ground level to prevent dust and debris blowing around the intake filter on windy days, and perhaps check / clean the filter more regularly. (we would generally recommend this for all pumps sited outside including fully weather proofed types).


The manufacturers ratings for the 45, 55, 70 Ltr and the 90 Ltr are (<55 to <60dB).

Our assessment would be that they are reasonably quiet when running into a highish load. The larger ones obviousley louder than the smaller ones. In summary If you had one of the smaller ones (up to the 90 ltr model) running near your pond with perhaps the sound of running water returning and you were not sitting right next to it intrusion if any would be minimal.

They are certainly not as quiet as the super silent ACO-97 Series range above or top of the range such as Medo. The super silent cased models are also completely weather proof .

These piston air pumps can also be operated from a remote siting with a larger bore pipe feeding the manifold. This can be a solution when utilising these budget priced pumps for use indoors.

We would always recommend that when siting a pump remotely the manifold is kept near to the Pond /Tank, and is connected with a larger bore tube from the pump. This often calls for a bit of improvisation.

One handy way this can be achieved when using fairly standard 8/9mm braided tube is with the use of a couple of cable ties Illustrated left

This method will normally take up a loose fit of up to 0.5 mm or so. If a somewhat larger gap needs to be caulked The good old PTFE tape will often come to the rescue. This is why PTFE tape is often referred to as Get out of a muddle tape

Negative trial when used with a Nexus
The ability of a 90 ltr piston to run a nexus filter was in our opinion a NO NO because of an unexplained increase in noise taking the form of a fairly loud resonance. This seemed to eminate from the nexus filter itself.

Without further evaluation we cannot at present recommend these pumps for use with a Nexus filter .

Hailea Hi-Blow a professionally developed pump for high air output in deep water.

We have run several tests using the Airtec range as the bench mark.

They are an excellent Hi-Blow power pump for the price, delivering a genuine high pressure in deep water.

They are all slightly noisier than the Airtec range and as noise is a very difficult area to assess relatively. A remote siting might be neccessary ande would recommend to bear this in mind.


Special note 3. WHAT PUMP DO I NEED FOR MY POND A straight forward and simple answer is certainly not the general rule.

The following criteria will always effect the final choice:-

1). Overall size of pond.
2). Capacity and filtration.
3). Type of pond? small fish, large fish, Koi fish.
4). Heavily / Lightly stocked.
5). Shaded, Direct sunlight.
6). Type and number of Stone/s or Diffuser/s.

Finally THE PRICE. Probably the most overlooked area of all. Normally higher the price better the pump.

EXAMPLE. A Hailea piston air pump may do a similar job to A Medo. But the Medo is always going to be the overall best performer.

Unless otherwise stated all electrical items are 220-240 Volts

6). High quality Piston & Diaphragm Air pumps Below are a selection of Air pumps that we consider to be some of the very best available.

MEDO ilustrated left is Piston operated and very quiet and probably the most reliable and well tested Air pump on the market today.

To give an accessment of the power that these Medo develop: The small LA-45 far left would probably equal the Hailea 45 ltr piston above times three (X3)

This time to the left is one of the better quality Diaphragm operated air pumps.

This one is the HI-BLO and has proved to be a very reliable.

Our final example of Class pieces of kit is the ever popular Air-Tec supplied by Evolution Aqua.

This one is also Diaphragm operated

Once again not much to say about these, the above names speak volumes.

We have no real favourite from these three superb pumps above.
But if called to make one comment we might suggest that the Medo Piston type is the quietest.

Having said that PLEASE NOTE as we have said before at various times No air pump is completely silent.

More information on theseTop of the range goto >>>>> Air Pumps

For information Air line fittings & accessories >>>>> Please click here

For more information all accessories >>>>> Please click here

For more information Air pump spares diaphragms etc. Please click here

Unless otherwise stated all electrical items are 220-240 Volts


Any stated specifications are for information only and do not represent anything other than our own interpretations, and may or may not be the manufacturers specifications.

Product Evaluation and testing Page still under construction


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