Neat way to store duration in Historian and show in PowerChart

Ignition
1

Hi, I have a device with an hour counter:

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I can read out those values through modbus, and have them available as seconds:

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I used an expression tag from this post OPC Tag Value Seconds to HH:MM:SS via Expression Tag - #5 by Kevin.Herron to convert the seconds to a HH:MM:SS string.

But I'm wondering what the best way would be to store these durations in the historian so I can show them in PowerChart as HH:MM:SS (and also see the trend lines go up each second)?
If I show the string in PowerChart it would just show "8079":
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Any suggestions on the neatest way to store and show durations in Ignition?