dGH Increasing for Unknown Reason

[phishfarm]

Hello All!

I am currently in the process of cycling my first moderately sized aquarium (25 gallon) and I have noticed in my regular testing that my dGH has moved from 4 to 7 over the course of the last three weeks. While it's moving into a range that I'd rather it be, since I don't know why it's occurring I'm not sure if I can stop it. I don't have a KH test, so I don't know what the readings are there.

To the best of my knowledge I am adding nothing to the water to cause this to occur. Substrate is "normal" aquarium gravel, decor is scant with scattered aquarium specific decorations (e.g. 1 silk plant, 1 plastic plant, and 1 rock/tree stump aquarium replica from PetSmart), and I am using a small amount of lava rock medium in the filter to add additional bio-media surface area(maybe this would cause the issue?).

I have another small aquarium (2.5 gal) using the same water source and it has not undergone this same shift. I guess my questions are these:

Is this normal?
Is it a "bad" thing?
What are some of the things I might be doing to cause this?

Can anyone shed some light on this?!? Any help is appreciated!!!

 

[krap101]

my dgh is about 4-7 2 . i wouldnt worry.

1 rock/tree stump aquarium replica from PetSmart),

when you said that did you mean a rock and a stump replica or same thing.

and whats the dgh of your tap? it could be that water evaporated and left a "line" when the water lvl went up the water disalved the "line" and hardened your water

 

[Menagerie]

I am using a small amount of lava rock medium in the filter to add additional bio-media surface area(maybe this would cause the issue?).

Maybe. It's times like this that I wish I remembered more chemistry. Krap had a point--check your tap water.

I don't have a KH test, so I don't know what the readings are there.

You should get one, that may help explain things.

 

[phishfarm]

Actually I think I discovered what the problem was. I was topping-off the water regularly, but I hadn't done any water changes yet, as I was waiting until I saw an identifiable ammonia trace before changing. This took approximately three weeks, so the minerals were just building up in the tank as the old water evaporated and the new water top-offs added more. Thanks to you both for your assistance!!!