My Kh Is Dropping

[blackdove]

I'm currently doing a fishless cycle on my tank (started at the beginning of Feb) and for some reason my KH (which was at 4-5 dKH initially) has started to drop of its own accord and of course the pH has followed suit. I first noticed it on Tuesday as the water seemed to feel acidic so ran a pH test and it came out at <=6.0 tested KH and found it at 0! I did a 50% water change which gave me 2-3 dKH and 7-7.2 pH. This has been stable until tonight when it has dropped down to 1-2 dKH and pH to 6.6-6.8.

The tank is 240L, has CO2 injection with a 4 dKH drop checker showing green, and I'm currently processing 10ml of Ammonia to 0 daily. I'm also adding KH2PO4 & Trace at half EI dosing as specified [topic="104737"]here[/topic].

Anyone have any ideas as to what is causing it to drop?

Chris

 

[Mr._Fishy]

Wait, so you are injecting co2 during a fishless cycle? Do you have plants? For some stupid reason, I tried to run a fishless cycle with a couple of plants and they were killed, so you might want to remove any plants. Are you injecting during the night? If you are, you really don't need to. Plants don't absorb co2 during the night which will cause co2 to build up causing your hardness to drop like a brick.

And how do you tell if water is acidic or alkaline? I honestly can't tell the difference.

 

[blackdove]

Wait, so you are injecting co2 during a fishless cycle? Do you have plants? For some stupid reason, I tried to run a fishless cycle with a couple of plants and they were killed, so you might want to remove any plants. Are you injecting during the night? If you are, you really don't need to. Plants don't absorb co2 during the night which will cause co2 to build up causing your hardness to drop like a brick.

I am running CO2 because I have plants in the tank and they are growng very well. CO2 is turned off 30mins before the lights and then on again an hour before the lights come on.

And how do you tell if water is acidic or alkaline? I honestly can't tell the difference.

With a pH test kit I'm assuimg you mean how did I feel it was acidic - well I don't know if I actually did as such. I put my hand in the tank to fish out some debris and the water felt tingly on my fingers so I assumed it was acidic and when I tested it, it was.

 

[Bignose]

The end products of the cycle are acidic. That's most likely the main culprit in your dropping pH. The CO2 is probably the second most likely culprit. Both will increase the amount of acid in the water.

And the tingle test is probably not the best way to tell if a solution is acidic or not. Put some lye on your hand and tell me that tingles too (it will and/or burn) but it's pH is above 10.

 

[blackdove]

The end products of the cycle are acidic. That's most likely the main culprit in your dropping pH. The CO2 is probably the second most likely culprit. Both will increase the amount of acid in the water.

Hopefully that's it. I've added some bicarb/baking soda to boost the KH back to 4-5 and it seems stable again atm. Another thought I had is that I have a lot of snails in there that came free with the plants. I'm assuming that the calcium for the shells has to come from somewhere but I wouldn't have expected such a swing. Anyway the cycle looks like it is coming to an end - the nitrite is down to 0.3 tonight so with any luck I'll have fish in next weekend

And the tingle test is probably not the best way to tell if a solution is acidic or not. Put some lye on your hand and tell me that tingles too (it will and/or burn) but it's pH is above 10.

Probably not, but at least it was an indicator that something was different and needed testing.

Chris