KH & GH

[Joy9]

Hello! I’ve had my tank about a year now so I’m relatively new to the hobby. In the past I’d only ever tested ammonia, PH, nitrite & nitrate but recently I decided to test KH & GH as I’ve had a couple of guppy deaths. I’ve read various articles but honestly I’m still none the wiser on what safe KH & GH levels are. I use the NT labs test kits and I got 10 drops for KH (I believe this is 178ppm) and GH was 11 (195.8ppm) but I have no idea if these are safe levels, I’d really appreciate some insight. For reference my tank is 125 litres and contains 5 guppies and 6 glow light tetras (plus ramshorns & pond snails). Thank you in advance for any help!

 

[TwoTankAmin]

Go here and read. it will make things a whole lot clearer and easier to understand:
https://fins.actwin.com/mirror/begin-chem.html

 

[Essjay]

There are no 'safe' levels for GH and KH as there are for ammonia, nitrite and nitrate. It depends on the species. Some fish need high GH, others need low GH, some are happy straddling the two. KH is not as important for fish as GH.

GH at 11 and above is OK for guppies; I wouldn't keep them in a lower GH. Glowlight tetras are OK as well, they are one of the tetra species than can live in hard-ish water.

 

[anewbie]

I find guppies do ok as low as 7 gh. Kh does have an impact esp for fishes that require acidic water. As a general rule live bearers (guppies, swordtails, mollies, ...) like hard water (which you have). Most SA fishes prefer soft water but some can adapt to harder water others cannot. Most loaches are soft water fishes; Lake Malawai fishes are hard water fishes. Some (not all) central american fishes come from areas of high limestone deposit and prefer hard water. Many asian fishes (not all) are soft water fishes (many but not all gourami, betta, ...). Many barbs are softish water but not as soft as sa or gourami.

 

[Colin_T]

Hello! I’ve had my tank about a year now so I’m relatively new to the hobby. In the past I’d only ever tested ammonia, PH, nitrite & nitrate but recently I decided to test KH & GH as I’ve had a couple of guppy deaths. I’ve read various articles but honestly I’m still none the wiser on what safe KH & GH levels are. I use the NT labs test kits and I got 10 drops for KH (I believe this is 178ppm) and GH was 11 (195.8ppm) but I have no idea if these are safe levels, I’d really appreciate some insight. For reference my tank is 125 litres and contains 5 guppies and 6 glow light tetras (plus ramshorns & pond snails). Thank you in advance for any help!

A GH of 195ppm is fine for guppies and close to ideal for them. However, it's a bit high for glowlight tetras. They should be fine tho.

The KH is fine too and less of an issue for fish. KH helps stop the pH from dropping.

The snails will be fine as long as the pH doesn't drop below 7.0 and it should due to the KH.