RO Water and GH. What should it read? - The Planted Tank Forum
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post #1 of 3 (permalink) Old 09-02-2016, 02:46 AM Thread Starter
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RO Water and GH. What should it read?

Curious. I shared with someone my RO water test results:

Ph 7.0
GH 4
KH 0

They told me that my GH should have read 0 after the RO system. I just bought the unit so I know it's not defective but I thought perhaps RO units have different specs and maybe by GH should actually be zero. It started at 15 so I guess I wasn't surprised that it still had some hardness.
Has anyone had a similar experience with their RO water?
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post #2 of 3 (permalink) Old 09-02-2016, 03:10 AM
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What are the units of your measurements?

4 ppm is a lot different from 4 degrees GH or KH

If your just using an RO system, then a reading like your seeing is possible. If your using an RO/DI system then you should get 0 for GH and KH.

You may have something not quite right with your RO or RO/DI system, for example a filter may not be seated correctly or the restrictor clogged.

If you really get into this area, a TDS meter can help a lot. Some can run inline so you can monitor the water in verses the water out.
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post #3 of 3 (permalink) Old 09-03-2016, 12:22 AM
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If you water went down from 15 dGH to 4 dGH than your RO system is definitely not working properly. It should be zero - RO normally removes at least 95% of the dissolved content and with good system it is more like 99%.
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