Skip to product information
1 of 1

NT Labs


NT Labs - Hardness Test kit

NT Labs - Hardness Test kit


To View Prices Login Or Apply For Account

Shipping calculated at checkout.

NT Labs Hardness Test Kit – Comprehensive Monitoring for Your Pond's Water Quality

Understanding KH (Carbonate Hardness): KH, also known as "total alkalinity" or "carbonate hardness," measures the buffering capacity of your pond water. This capacity indicates how well the water can resist changes in pH.

What is the Correct KH Level? Maintain a minimum KH level of 4 dKH at all times, with a more desirable range between 6 and 8 dKH. This test kit measures KH in dKH, where one dKH equals 17.8 ppm as CaCO3.

What to Do if the KH Level is Wrong:

  • Check the KH level of your tap water. Regular water changes are sufficient if the tap water KH is above 6 dKH.
  • If tap water KH is below 6 dKH, use a KH buffer like KH – Buffer Up to maintain a suitable level in your pond.

How to Use the KH Test:

  1. Ensure the test tube is clean.
  2. Collect a 5 ml water sample into the test tube.
  3. Add one drop of the KH reagent, mix, and observe the pale blue color.
  4. Continue adding drops, one by one, mixing between drops until the color changes from blue to yellow.
  5. The number of drops needed for the color change equals the KH value in dKH.

Understanding GH (General Hardness): GH measures the total minerals dissolved in water, with water hardness ranging from 'soft' to 'hard' based on mineral content. Hard water can lead to limescale buildup.

What is the Correct GH Level? For pond fish, the ideal GH level is between 8 and 12 dGH. This test kit measures GH in dGH, where one degree equals 17.8 ppm as CaCO3.

What to Do if the GH Level is Wrong:

  • Test the GH of your tap water. If too hard, consider using alternative water sources like reverse osmosis water to lower GH.
  • In ponds, where rainwater may lower GH over time, use GH & Minerals Up to boost GH to a suitable level.

How to Use the GH Test:

  1. Ensure the test tube is clean.
  2. Collect a 5 ml water sample into the test tube.
  3. Add two drops of GH A reagent, mix, and observe the dark pink color.
  4. Add one drop at a time of GH B reagent, counting the drops between mixing until the solution changes from pink to blue.
  5. The number of drops needed for the color change equals the GH value in dGH.

Maintain the balance of KH and GH in your pond with NT Labs Hardness Test Kit, ensuring optimal water quality and a healthy environment for your fish. Trust NT Labs for precise water testing solutions.


Fast and Reliable Delivery Service for Your Convenience

At SKS Wholesale, we understand that timely delivery is crucial for your business. That's why we are committed to providing you with a quality, professional service that ensures your products reach you swiftly and efficiently.

Delivery Charges:

  • For non-bulky items under 1.5mtrs (including bulbs & liquids), the delivery charge is £9.50 + VAT for the first 20kg (additional 28p per kilo after 20kg).
  • Pipework and Oversized Parcels over 1.5mtrs have a delivery charge of £15.00 + VAT for the first 20kg (additional 28p per kilo after 20kg).
  • If your item(s) can fit a 5kg Courier pack and do not contain liquids, they can be shipped for £6.50 + VAT.
  • For item(s) that fit a 1kg Mail pack and do not contain liquids, the shipping cost is £5.50 + VAT.
  • Bulky items such as drum or bead filters require pallet shipping, starting from £45.00 + VAT.
  • Non-bulky orders to mainland UK over £1000 Excluding VAT will be shipped for free, up to a value of £55.00.
  • Orders going to remote places such as the Scottish Highlands and Northern Ireland may have different rates (please contact us for details).
  • To ensure your privacy, all orders will be shipped with unbranded packaging, without any marketing material.

We are dedicated to providing a fast delivery service and aim to dispatch your orders as quickly as possible. However, please note that while we strive to meet delivery expectations, it is important to understand that delivery times are not guaranteed and should not be solely relied upon. SKS Wholesale cannot accept responsibility for any delays that may result in job disruptions or hold-ups.

Placing an order is simple and convenient:

  1. Telephone: Give us a call, provide the product code and details, and our friendly team will assist you in placing your order.
  2. Online Store: Visit, browse our wide range of products, and place your order online through our secure platform.
  3. Email: Send us an email with your details and the product code, and we will process your order promptly.

If you have any questions regarding delivery times or costs, please don't hesitate to contact us. We are here to ensure a smooth and hassle-free experience for you.

At SKS Wholesale, we prioritize your satisfaction and are committed to providing reliable delivery services for all your wholesale needs.


    **Although we try our best to provide a fast delivery service, this is not a guaranteed service and should not be replied upon. SKS Wholesale can accept no responsibility for delayed orders that result in jobs being held up or disrupted.**


    Welcome to SKS Wholesale's Return Centre. If you need to return an item to us due to damage, warranty claims, or any other reason, we have provided a simple and convenient return form for you to complete. Please carefully read and follow the instructions below to ensure a smooth return process:

    1. Complete the Form: Fill out the form below with all the required information. Make sure to provide accurate details to expedite the return process.
    2. Unique Returns Number: Upon submitting the form, a unique returns number will be generated for you. This returns number is crucial and serves as YOUR personal identifier for the return. Please make a note of this number and keep it safe.
    3. Include the Returns Number: When packaging the item for return, remember to include the generated returns number along with the product. This allows our dedicated team to efficiently process and track your return.
    4. One Form, One Code: Please note that only one form should be completed per item returned. Each item requires its own unique returns number. If you are returning multiple items, kindly fill out a separate form for each one.
    5. Submitting the Form: Once you have completed the form and obtained the unique returns number, click the "Submit" button at the bottom of the page to send us your return request.
    6. Return the goods: Please send all returns to: SKS Wholesale Limited, Beechcroft, 47 Waterloo Road, Hainford, Norwich, Norfolk, NR10 3AX

    If you have any questions or need assistance with the return process, our friendly customer support team is here to help. Feel free to reach out to us via phone or email and we will guide you through the necessary steps.

    Thank you for choosing SKS Wholesale. We appreciate your cooperation and look forward to assisting you with your return.

    Items sent back to us without this form will not be looked at. SKS does NOT cover the cost of returning goods, SKS May refund the cost of returned goods if/when they are deemed to be Faulty & under Warranty

    **IMPORTANT** As the dealer/supplier/installer it is your duty to inspect the
    product prior to returning it to us. You must check for user error/misuse or lack of
    maintenance. If a product is returned to us and simply requires cleaning or
    servicing you will be charged for us to do this and for any carriage charges

    View full details

    Product guide

    Our extensive product guide will give you all the details and product code you need to place your order.

    • Stock Levels

      At SKS Wholesale, our stock levels are updated throughout the day so you can buy with confidence. Our commitment to providing real-time updates ensures that the information you see on our website is always accurate and current.

    • Contact Us

      We value our customers and strive to provide excellent customer service. Our knowledgeable and friendly team are available via email and telephone, to assist with your orders or questions about our products.

    • Open a Trade Account

      We make it easy to open a trade account with us. Simply complete our trade application form, and our account manager will be in touch with you shortly. As an account holder, you'll enjoy a range of benefits, including access to our extensive product range, competitive pricing, and support from our expert team.