Bottle label and manufacturer website disagree: which dose applies?

Compare like with like first

• Product and formulation: match the full name, strength and application.
• Units: distinguish litres, US gallons and imperial gallons.
• Timing: separate one addition, daily use and a whole course.
• Purpose: standard conditioning, another use and special circumstances may have different instructions.
• Version: retain the label, leaflet, pack size, market and batch details.

A different reference is not automatically a contradiction. First check whether the documents concern the same product and situation.

A documented example: Seachem Safe

Safe’s current webpage says its directions supersede prior packaging, while its FAQ also says package directions are correct for the formulation supplied. The page distinguishes the 50 g pack from other sizes for some uses. These statements do not establish which reference applies to every older pack.

If your pack differs, send Seachem the pack details and both references. Do not combine the two versions or select whichever produces the preferred quantity. The Safe calculator covers its listed modes; it cannot identify a formulation from a photograph it has not received.

Make a useful evidence record

A question to send the maker

“My pack is this exact formulation, size and batch. The supplied instructions say this, while this webpage says that. I intend to use it for this purpose in this water volume. Which instructions apply to this pack, and is there a correction or updated leaflet?”

Ask whether the answer applies to your country’s formulation. A retailer’s summary or a forum response about a different pack may not resolve the discrepancy.

Update the record after clarification

1. Keep the original evidence alongside the answer.
2. Record the applicable reference, timing and conditions.
3. Recheck any saved calculation against that reference.
4. Report a calculator discrepancy with the source and expected result.

Do not obscure the original label with an improvised instruction that another keeper could mistake for manufacturer guidance.

Common questions

Should I average the two doses?

No. An average is not evidence that either formulation was correctly identified.

Does a safety data sheet settle the treatment dose?

Not necessarily. Hazard and handling information is not automatically a course instruction.

Can DoseMyTank choose the older or newer version for me?

The calculator shows its supported reference and scope. It cannot resolve an undocumented version conflict; obtain clarification first.

Sources and review scope

• Seachem Safe directions and FAQ — the disclosed packaging/webpage conflict

Reviewed 28 October 2026. Worked examples and worksheets are DoseMyTank explanations, not laboratory tests or evidence of a particular aquarium’s response. Manufacturer instructions apply to the exact product, device and conditions described. Obtain clarification where your supplied instructions differ.