Ammonia Problems

I wonder if you have a very low KH. The end product of the nitrogen cycle (nitrate) is acidic, as are other chemicals excreted by the fish. If your KH is very low there will be no buffer to stabilise the pH and the pH would fall.
Do you have any wood in the tank? That would also release acids (tannins) contributing to the problem.

You can buy testers for KH but the cheapest first step would be to ask a shop to test a sample of tapwater for both KH and GH. If they turn out to be low, especially KH, there are things you can do to increase KH, GH and pH. But you need to check your KH and GH before doing anything.

You have 2 choices. Either do a fishless cycle using ammonia or steal a bit of media from the current tank, put it in the new tank's filter and do a fishless cycle using ammonia. The second way should be quicker as getting the bacteria started is the slow bit; any bacteria you can add will speed things up.
Though with the problems you've had recently, if you want to do option 2 I'd wait till the current tank has settled down.

hi, i have tested my kh and gh..  sat 18th oct….  gh 120… kh…0    thurs 23 oct  gh 180….kh nil to 40…..



  nitrites and nitrates nil and ph 6 each time  …  don't know what they mean, but i guess you do  ;-)  is there anything i can do to get ph up to 6.6 to 7 , thanks

Hi Fruitbat,

I think Sue called it a while back:

I wonder if you have a very low KH. The end product of the nitrogen cycle (nitrate) is acidic, as are other chemicals excreted by the fish. If your KH is very low there will be no buffer to stabilise the pH and the pH would fall.

KH is carbonate hardness and basically helps keep pH stable, as such, because yours is so low this probably explains why your pH is dropping so rapidly. What I'm not sure about is why the KH in your tank is lower than from your tap - I'm sure someone with more knowledge in this area will advise.

It's boiling the water that removes KH. Carbonates decompose with heat. That's why carbonate hardness is called temporary hardness.

Are you using strip testers? They are not the most accurate. But 40ppm KH is just above 2 German degrees - and 4 degrees is the lower limit for water stability. Even 80 is a bit on the low side. I think this low KH is the cause of your pH problems. It's lower in the tank because it's getting used up, and possibly the inaccuracy of the strips.
Your GH at 180ppm is classed as moderately hard.

You could try putting something made of calcium carbonate in the tank. Chunks of limestone rock; shells;  pieces of coral or crushed coral; aragonite sand. Inside the filter is the best place for crushed coral or sand, if that could be managed. These all dissolve slowly, increasing both KH and ph, which you want, and also GH.
The other alternative is to get some remineralisation salts of the kind made for use with RO water. You would need to use them at every water change. The best way would be to add the salts to a bucket of water till you got the KH where you want it (around 100ppm) and add that concentration when you do water changes. Using just the amount for the new water rather than the whole tank would increase the amount in the tank slowly.


And the filter bacteria need carbonate in the water  and a high pH to multiply. You might well find that getting more carbonate into the tank helps the ammonia too as the bacteria will be able to multiply faster.

That would be perfect.

What fish do you have left?

I think the remedy is to treat your water as though it was RO water and add some remineralisation salts. You wouldn't need to add much, just enough to get your KH above the danger mark. But you would need a liquid GH and KH tester set to do this.