Tap water gh high, tank water gh low

[Koppriecht]

Hello

My tap water has a gh that is higher then 12 but my freshwater aquarium water has a gh of one or two drops. I am trying to do a fishless cycle and I am afraid the low gh could stall it. Also, it is strange that the gh from the tap is high and in the tank it so low, it is the same water. I do have some rocks in the tank but that should raise gh I thought. Any ideas?

confused


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[dalto]

What else is in the tank/filter? I don't think low gh will effect your cycle. It is low pH that can effect it.

All the same 12->1 is an extreme difference. Are you sure the test results are accurate?

 

[Koppriecht]

Did the test 3X and it was the same. The filter is a new marineland. I have Malaysian driftwood in the tank too. I did use some Dr Tim's one and only live bacteria as well, forgot to mention that.


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[dalto]

The tannins released by driftwood can soften your water but 12->1 would be extreme.

How often are you doing water changes and how much water are you changing?

 

[Koppriecht]

I am only 4 days into the cycle so I haven't done any wc yet. Do you think I should do one and then re-test?


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[dalto]

Do you have a ph test? I would check that if you can.

 

[Koppriecht]

8.2 ph


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[dalto]

8.2 ph

Tank or tap?

 

[Koppriecht]

Sorry, in the tank. I am at 4ppm for ammonia, pretty high. Some of the rocks are not specifically aquarium rocks. Could they be the culprit?


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[Koppriecht]

Just started seeing Nitrites. At .5 ppm today where as 0 ppm yesterday.

 

[mudraker]

Did you try leaving some tap water out overnight and then testing the GHH after 24 hours?

I know some tap water is prone to PH drops after it sits out. Same could be true of GH.

 

[Koppriecht]

Good point. The tap water was tested right out of the faucet.


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[Koppriecht]

How long should the gh test sit by the way? I have the API gh and kh test.


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[mudraker]

They don't sit. When they turn color after adding one drop at a time you are done.

 

[Koppriecht]

Well I tested the water in my 2nd tank that has fish in it and it has 161 ppm GH where as the new tank has 36 ppm. The KH is the same in both of them, 260 ppm range. I really am starting to think it is the "special" rocks in the new tank lowering the GH. Should I do a water change once they are removed and then re-test.

 

[Koppriecht]

I took the rocks out of the tank but haven't done the water change yet, it is a 110 gallon tank. So a low GH (2 dkh) won't hurt my cycling?

 

[Koppriecht]

Looks like one of the rocks ( from the pet store ) has some weird growth on it.