Do I need to raise KH?Updated a month ago

Don't I need at least some KH? 

No if you are keeping most commercially available soft water livestock/plants. 

Most aquatic plants grow better at low or zero KH, as does most soft water fish. Many buffers also make use of phosphate based chemicals that will raise your PO4 levels significantly. 

In Southeast Asia where most tap water is naturally 'soft', tanks thrive at near 0 KH. 

Low pH is also not a concern-we run most of our tanks at pH 5 plus.
Read more about this topic here.

However, if you are paranoid about have low KH, APT Sky Plus raises both GH and KH. It raises KH/pH slightly for folks that are worried about low KH/pH ranges.

Higher KH levels are required if you are keeping hardwater livestock (many African rift-lake cichlids, some species of snails and shrimp). Aquasoil should not be used in such setups as most aquasoils contain peat which will lower KH/pH.

Many of our tanks run at pH 5+ when CO2 is at peak saturation. 

Livestock from soft water areas do well in low KH tanks.