Mixed salinity readings from different hydrometers


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Feb 9, 2020
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Hi, my 30 G tank is currently going through its first cycle. No livestock in it yet. Cycle started 2 days ago with Dr Tims ammonia and Dr Tim's One and Only.
I have 2 hydrometers: this one and this one. They are giving different readings.
The first one is showing 1.021 and the second is 1.023.

Whats my best course of action? Its not urgent as there are still a few weeks before the cycle will complete and I get any fish, but would be good to know how to track EVERYTHING confidently, long before I do start adding livestock.

I could take the midway point between them and assume it is 1.022. But if one of them is wrong, the other is right near the border between acceptable and too high/low.

How often do you have to empty your skimmer collection cup?

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