Dramatic Unexplained Raise in Gh

[MajorMediocre]

Hi everyone, new to the hobby here. I just set up a tank a little while ago, ( It doesn't have any fish in it yet.) Before even buying the tank, I tested my tap water and the Kh was about 3, Gh about 4. I planned what stuff I wanted in there, with the video I might buff the Gh a little.

The tank has been full for about a week and half, and the Ph is stable at about 7.4, as the Kh at about 3-4. However, the Gh started at 8 and over the course of the rose to 15.

Does anyone know why this might be the case? I have added another to the water but conditioner. The only two things I thought it might be is the gravel or a small mineral block I put in their for snails and shrimp. However, the packaging for the gravel claims its inert, and the block is so small I can't imagine it would alter the water that much.

I recently did a roughly 25% water change, but after a couple of days that's done nothing but temporarily lowered the Ph.

I know a solution is to dilute the water changes with Ro/DI water, but I'd rather not buy expensive equipment if I can help it. Also I'm not confident in my ability to keep the water stable if every week I'm diluting or not diluting the water.

I've also seen the advice "choose fish for your water, don't change the water for fish". If so, does anyone have suggestions for different fish?

Thanks in advance for any advice.

 

[Essjay]

When a GH rises like this, the first thing to suspect is something in the tank. I suggest to start with setting up a few tubs of water. Leave one as just water, put the mineral block in the second, some gravel in the third and anything else you can think of in other tubs. Test the GH in each tub straight away, then again in a few days. The tub with just water is the control, it shows whether or not any change is due to the water alone. If any of the tubs show a rise in GH, you've found the culprit.

 

[MajorMediocre]

When a GH rises like this, the first thing to suspect is something in the tank. I suggest to start with setting up a few tubs of water. Leave one as just water, put the mineral block in the second, some gravel in the third and anything else you can think of in other tubs. Test the GH in each tub straight away, then again in a few days. The tub with just water is the control, it shows whether or not any change is due to the water alone. If any of the tubs show a rise in GH, you've found the culprit.

Thanks, that's a great suggestion.

 

[Ichthys]

Do what Essjay says. I suspect the mineral block. How big is it and how big is the tank?
Don’t think about fish till you get this sorted.

 

[MajorMediocre]

Do what Essjay says. I suspect the mineral block. How big is it and how big is the tank?
Don’t think about fish till you get this sorted.

I have the tubs set up now. The tank is 10 gallons, and the block is small enough to fit on the palm of my hand.

 

[Ichthys]

That sounds very big for a 10g tank.