Is high GH an issue?

[Lefty469]

Tank tested is a 55 gallon lightly planted (just added Anubias Barteri and Scarlet Temple a few weeks ago.  The tank has been running for about 2 years with occasional gravel vacuum and top offs (no water changes).  My GH is through the roof.  The GH in my tap water is 4 drops.  My tap water has chloramine.  I don't use prime or other conditioners prior to adding.  I let the water sit for minimum of 24hrs, and have done things this way for years.  I do add Flourish, and recently began adding trace.  The substrate is eco-complete black, about 2-3 inches deep.

So here are parameters.  All tests done with API liquid tests. 

• pH 7.8
• Ammonia 0 ppm
• Nitrite 0 ppm
• Nitrate 40 ppm
• KH 4 to 5 drops (starts to turn color at 4, fully changes at 5)
• GH 28 drops
• phosphate .5 ppm

The article, The Fish Keeper’s Guide to pH, GH, and KH, suggests that reducing water changes would make the tank more acidic and help reduce GH.  Clearly not in my case.

[Fish Folk]

As I understand it, KH is a measurement of bicarbonates & carbonates, but GH is a measure of calcium & magnesium.

What is the GH of your tested tap water before adding to tank? Is the high calcium & magnesium from your source, or from your tank? 

[Lefty469]

Just now, Fish Folk said:

As I understand it, KH is a measurement of bicarbonates & carbonates, but GH is a measure of calcium & magnesium.

What is the GH of your tested tap water before adding to tank? Is the high calcium & magnesium from your source, or from your tank? 

4 drops, so I suspect from the tank.

[Fish Folk]

Maybe it just needs a ton of plants to draw down the high mineral content? 

[KaitieG]

My understanding is that GH minerals generally do not evaporate, so you can have your GH climb if you're just topping off due to evaporation.  As the water evaporates, the minerals are left behind and tend to build up.  That said, my GH is as high as yours and that's out of my tap AND in my tank--guppies like it 🙂