Kh and gh question

[JamieLikesPlants]

I am seeing conflicting information regarding kh and gh and I would like some advice from people who have a good understanding of this subject.

My water out the tap has a kh of 2, and a gh of 4, and a ph of 7.5.

My first question is concerning mainly the kh, I read that ph will fluctuate at a kh of 2 or lower from some sources, but I am also reading that this only really happens from people who use co2, so will My ph be an issue with this kh?

My second question is regarding whether my water is considered soft or hard?

I do not plan to use co2, I plan to keep south American dwarf cichlids and tetras.

Also the tank has been cycling about 2 weeks, tank is already heavily planted, and I have been dosing 1ppm of ammonia and so far ph has remained stable at 7.5, tank has some seriyu stones as well and I have heard those raise kh.

All advice is appreciated!  🙂

Edited April 9 by JamieLikesPlants

[face]

Low kh don’t necessarily mean unstable ph my kh is undetectable and it takes weeks before my ph drops so as long as you maintain the tank you’ll be fine 

your water is more on the soft side 

as for the stone I’ve never used it but if it’s not effecting your water by now it’s probably not going to 

[Biotope Biologist]

Seiryu stone don’t alter kh at all. AFAIK its igneous rock with quartz veins. But im not a geologist.
 

Kh is a buffer to ph. It will absorb swings in ph. Gh is general hardness and is magnesium and calcium. Luckily you can disregard this measure as amazonian fish are well adapted to low-no gh. 
 

If you plan on having plants you will have co2 which will lower your ph. But co2 is a weak acid so it doesn’t affect it much. As plants both respire and photosynthesize. Also if you have decaying matter such as wood or leaves your pH will also lower quite a bit.

[knee]

Your ph will not fluctuate as long as you have a kh reading. Not sure if you have actual seiryu but most seiryu sold now are actually Ying Stones from China, a type of limestone that will increase both gh and kh (also raises the ph).

Your ph is already at 7.5 so I'd say that's not the the acidic side. It will dissolve the limestone at a much slower rate, or not at all. That's probably why you don't see a change in the ph. 

Icelandic lava rock and yamaya stone are both inert and very similar to Seiryu if ever you're looking for replacements.