PH, GH, KH results...what does it mean? And can I add fish?

[hoppingtetra30]

Ive just finished setting up my new 75 gallon planted tank and Im wondering about the water quality tests. Im familiar with Ammonia, Nitrate and Nitrite, but I dont know aboug the rest. I tested my PH and it seems to be neutral at 7.0 (good thing?). The GH is less than 20mg/L, and the KH is right about 20mg/L. What do these results mean?

Just for reference it is a 75 gallon tank, planted, low light, no CO2.

Also, is there something I should be watching for before I add fish, or can I add a few and cycle as usual? (Ive had fish tanks before...just been awhile and never planted)

 

[AdamsAquarium]

You can add fish when you are ready. A ph of 7.0 is neutral, correct. The gh is general hardness. You have medium to soft water, which is ideal for most fish. Kh is the test of alkalinity which directly adjusts according to the gh and ph. All 3 are stable and safe for the fish, in fact if it is a tropical aquarium, that's perfect water to use

Sent from my SM-N900V using Aquarium Advice mobile app

 

[hoppingtetra30]

Thanks for the response! Ive read that its better to have a higher KH if its a planted tank...but I think thats only if you're using CO2 (which Im not), is that correct?

Also, when I look at some of the fish Im considering the recommended KH is much higher...will they adapt ok?

 

[Rpeinhardt]

All aquariums benefit from a carbonate buffer to some extent but planted tanks, and particularly CO2 injected planted tanks, especially so.

Generally speaking, stability of parameters is infinitely more important than accuracy. Fish adapt.

 

[hoppingtetra30]

Ive read that its more important to keep it stable, so I dont really want to add anything. At the same time Ive read that Rainbows like a higher KH/GH than what I currently have and they will be incorporated into my tank soon...Im just worried about the Rainbows.

 

[threnjen]

I have naturally VERY soft water from the tap, as in the gH and kH test will turn with the first drop. I maintain these values higher through a combination of crushed coral and a remineralizer (like Seachem Equilibrium). The fish will adapt but it's true the plants will appreciate the addition of some magnesium and calcium. A bit of crushed coral in your filter is likely all that is really required, however. That will create a kH buffer in your tank without any need for additional additives. With low light plants I probably wouldn't go any further.

 

[Fishperson]

Yes, a higher gH/kH is helpful for plants but with low light plants it shouldn't be an issue. It's only once you have demanding plants that the lower amounts of those nutrients, like calcium, becomes a problem.