Raising low kh but have hard water

[Brad J Reinert]

So I tested my water today in my 10 gallon tank and found that I had between 0-40 ppm kh and as a result my ph was closer to 6.2. 
I have heard Cory say to use crushed coral but my gh is over 300 ppm and I don’t want to raise my hardness any more any suggestions? 

[modified lung]

You can add sodium bicarbonate (baking soda) which will add to your KH but not your GH. It will also add sodium in the process but not very much. You always need to be careful when messing with you KH and pH. It's not always worth the effort.

[Hobbit]

^ Baking soda works great if you want to use something you have on hand. I’ve used it quite a bit in the past. A little goes a long way.

If you’re okay with purchasing something, you can buy potassium bicarbonate powder on amazon. Any plants you have will love the potassium, and the bicarbonate will raise your KH and pH.

Neither of these will raise your GH at all. 🙂