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Frequently Asked Questions - DelAgua Kit
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Frequently Asked Questions - DelAgua Kit

Are my results still reliable if I have incubated for longer than the suggested 16-18 hours?

The reason why 16 to 18 hours are needed for the colonies to form, is that this is the best time to see and count the colonies. When you leave the colonies in the incubator too long, they can start merging to make big colonies. This means that you could count one colony, even though there could have been multiple. This would give you a false reading. It is best practice to start again.

I've come to record my results but have noticed that the colonies are different colours? What does this mean?

Only count the yellow colonies - these are positive coliform results. The presence of bacteria will be indicated by the change of colour of the pad from red to yellow. If no colonies are apparent but the colour change has still occurred, this should still be recorded as a positive result. Do not count colonies that are transparent, red/pink or blue/grey. These are bacteria which do not ferment lactose and cannot be identified without further study.

Can you use a different broth (other than the MLSB supplied with the kit) to test for other parameters?

Yes, you can. We offer a few different broths that can be used with the kit. We offer a broth that shows E. coli as a separate colour, so that it can be enumerated separately to coliforms. Please bear in mind this needs to be broth that can be used for membrane filtration and not agar for example. Please contact us if you require more information.

Can I take a DelAgua Kit on a flight? Do I need any paperwork?

Yes, the DelAgua kit can be taken on a flight. If you intend to carry it in your hand luggage we can supply a battery safety data sheet to take with you (please check with your airline regarding hand luggage weight/size restrictions) or the kit can be checked in.

The DelAgua kit doesn’t include any hazardous items, however if you add additional hazardous reagents to your order then these will need shipped. We can also arrange delivery of the DelAgua kit to your destination if that is required.

How do I find out if there is a distributor near me?

Information about the distributors we have in different countries can be found here.

If your country isn’t listed, but you do require help with import for example, we may know someone that could help you, so please just get in touch.

How long is the kit likely to last?

The lifespan of the DelAgua Kit is approximately 10 years - however we've had reports of longer! The kit is made from high quality components and housed in a tough fully waterproof pelican case so it's built to withstand the toughest terrains.

We need a large quantity of DelAgua Kits for a water testing project – what do I do next?

Get in touch! We can talk about specifications, pricing, delivery, lead times and also arrange training via Skype for you and your team. Please just contact the office and we can put a plan together with you.

Help! My manifold is stuck on the vacuum pump!

The vacuum cup is tricky to get off the manifold sometimes, especially when it is new. To keep the vacuum the cup is made too tight and will loosen a little bit with use. Please make sure it is greased properly before use. You can use the funnel as a lever, to try and remove the top part this way. If it does get fully stuck you can place the vacuum cup in hot water, and leave it there until it comes off.

I can’t source distilled water to prepare the media with – are there any other options?

 We would strongly recommend you source distilled water however we appreciate this isn't always possible. Some alternative options are:

  • A high quality bottled water that has not been treated with chlorine or any other disinfectant that has a residual activity.
  •  Rainwater. Collect a sufficient volume of rainwater in a clean container and leave it to stand overnight to allow any suspended matter to settle out. Carefully pour off the water into a separate clean container. Alternatively, the rainwater can be clarified by filtration through a membrane filter or, more quickly, through one of the membrane pads.
  •  Water from a well-protected groundwater source. Groundwater from a well-protected source is usually suitable for preparing the medium. However, check the pH of the water before use to be sure that it is not too acidic or alkaline.
  • Sodium Thiosulphate tablets can be used as a dechlorinating agent. Add two tablets to 500ml water that may contain chlorine and shake until they are completely dissolved. The water will then be suitable to use for medium preparation. These tablets are available from DelAgua.
  • De-ionisation packs can be used in situations where distilled or de-ionised water is not readily available. DelAgua are also able to supply de-ionisation packs.

For any other questions, please don't hestitate to get in touch at

Author: DelAgua

Publish Date: 14.08.2019

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