Planted Tank Guru
Join Date: Jun 2012
Location: Gainesville, FL
You're comparing apples to oranges. TDS is total dissolved solids. KH and GH are measures of the amount of various molecules in water.
Let's say you add 1,000 mg of a mixture of sugar and salt to a liter of water. You will be raising the TDS 1,000 ppm. What's the PPM of sugar in the water? Well we don't know because we don't know the amount of sugar in the mixture. It works the same for KH and GH. Sure you may add enough to raise TDS to whatever you want. However, the KH or GH will depend on the mixture. See the difference? Hence the reason Marcel suggested using chemicals to target GH specifically.
If you don't want to spend a fortune on special shrimp GH booster I would use individual chemicals as Marcel suggested.