Is there a right/wrong side to use these filters?

Standard Methods says that the filters should be used ‘wrinkled side up’. On our filters you can see the imprints of the mesh screen that we use to support the filters during the washing step. This is the ‘down’ side.

Ohio EPA requires certified weights to verify the accuracy of the balance, do you think checking the weight of a Double Weigh filter could be an approved substitute for the certified weights?

Our DoubleWeigh filters are not certified weights and cannot be used to calibrate balances. You will need to use a certified weight set to calibrate your balance prior to use for solids testing.

Are double weigh filters returned to oven after the determination of first weight for second drying cycle?

Yes they are. The pans are printed with only the first weight on the label. Both weights are available by entering your box or filter ID at http://www.envexp.com/filterdata

Which weight is most accurate and should be used?

Standard Methods does not specify which weight should be used once the preparation of the filters is completed. Some laboratories use the first weight and have the second weight merely as a verification of stability. Other laboratories use the second weight as that is the most recent weight reflective of the final condition of the filter. Your laboratory SOP and the direction from your accrediting body should give you guidance on which weight to use.

Hi there, what is the price on the 47mm Double weighs?

All of our pricing is available online by logging into your customer account. If you need help setting up or accessing your account please call our toll free number 1-800-343-5319 and speak with our customer support team.

what is the effective pore size of these filters?

These are binderless, glass fiber, 1.5 micron filters as specified in the methods for total suspended solids.

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