Confused By My Water Hardness

[Sexy Rexy]

Good Morning Fish Heads,
I have a water quality question for all of you. I have been working on keeping all of my water parameters in check but have an interesting problem that I’m hoping you can help me with. When I check my water hardness in the tank it comes up as a whopping 280 PPM. If I check the water directly from the tap, it’s close to 0 PPM. Any ideas why this is? I do a weekly gravel clean and a twice a week 20-25% water exchange. I’m baffled.

 

[Byron]

Good Morning Fish Heads,
I have a water quality question for all of you. I have been working on keeping all of my water parameters in check but have an interesting problem that I’m hoping you can help me with. When I check my water hardness in the tank it comes up as a whopping 280 PPM. If I check the water directly from the tap, it’s close to 0 PPM. Any ideas why this is? I do a weekly gravel clean and a twice a week 20-25% water exchange. I’m baffled.

If those numbers are correct there is something calcareous in the tank that is dissolving calcium into the water, thus increasing GH. The pH likely goes up too (does it?) though it may not, depending. The substrate material is the most likely suspect, or any rock in the tank. We have another recent thread where the cement in the internal background was dissolving calcium and increasing GH. You could be adding minerals with additives, though I would not suspect to this degree. GH has a significant impact on most fish, so it is important to sort this out.

 

[Colin_T]

That's a significant jump in GH over a week. Are you sure the testing is done correctly?