It's all about chemistry - again.

[Jan Cavalieri]

For the life of me I cannot get my newest tank to cycle. (my first one did it perfectly). It's a 29 gallon glass that has 2 zebra danio's in it (backstory - one mean danio is responsible for the death of a number of his peers and all the danio's were upsetting my 1st tank because they can be annoying to watch. So I put the remaining danio's in a tank I had just started cycling with a little ammonia to keep the other tank fish happy. Anyway that big zebra killed several more fish - actually saw the last one - so I was down to 3. Decided to remove the bully today and put him in a little 6 gallon tank I'm cycling by himself. Now the other two can eat again.

Back to the problem. The 29 gallon tank with 2 zebra's is getting worse each day. Yesterday I did about a 70% water change (was supposed to be 50 but I walk slow and barely got it off in time), Today I measured everything and some of it is twice as bad as I was - or at least as bad (is it a logarithmic scale?). When I refilled it I added Prime to declorinate the water. I know the stat's on our water without fish or anything and it's not our water causing the problem - zero's across the board.

It isthese are readings taken after I put in a piece of filter from a cycled tank)
GH: 50 ppm - no change since I first sat up the tank
KH: 50 ppm - no change since I first sat up the tank
Ammonia: 2.0 (it was 1.0 before the water change)
Nitrites: 1.0 (it was 0.5 before the water change)
Nitrates: 10.00 (it was 10.00 before the water change)
PH: 7.6 (it was 7.4 before the water change) - this makes sense our city water PH is in the 9-10 range

The filter is some cheapo filter that stuffs a few thin things in a bag and ties it shut and tells you to switch it out every month. Since a while ago I was getting NOTHING but Ammonia - I added a thin slice off the sponge from my other 29 gallon tank stupidly thinking it would give the tank some bacteria to break down that ammonia - and it sure did - but it also did a lot of damage even to Ammonia which was 0.25 before I added the piece of sponge which took it to 2.0

The fish are still alive and behaving like normal fish, which is to say, less active than when I had the bully in the tank (I just removed the bully a few minutes ago - also to an uncycled tank) The bully remains excited, looking for a victim.

So - should I remove the sponge before it does any more damage and continue to do water changes as often as I have the energy for? - or leave the sponge and see what happens? or remove the sponge and see what happens?

 

[PheonixKingZ]

These are what your tank readings should be.....

ph: 7.4-7.6

Ammonia: 0ppm

Nitrite: 0ppm

Nitrate: 0ppm

@Byron is a personal favorite when it comes to water chemistry, he may be able to help you, good luck!

 

[Colin_T]

Adding a piece of sponge from an established filter is not going to cause an ammonia spike.

If you remove and replace the filter pad, that can cause ammonia levels to build up, depending on what is in the filter pad.

If the filter pad has an ammonia adsorbing granule in (something like Zeolite or Ammogon), doing a big water change with water that has a different temperature or chemistry, can sometimes cause the Zeolite to release ammonia that it has adsorbed.
Ammonia adsorbing granules are usually white and feel like hard chalk.

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The GH and KH are not going to change rapidly unless there are lots of fish in a tank. Even then the GH won't drop much but the KH might.

The KH (carbonate hardness) helps stabilise the pH and neutralises acids in the water. A couple of small fish will not produce much acid and the KH won't drop much.

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Check your tap water for ammonia, nitrite and nitrate.

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I would replace the filter pad with sponge and let the tank cycle. Add a heap of floating plants (Duckweed or Water Sprite) to use some of the ammonia. Feed the fish a little bit every couple of days. Do big water changes to dilute any ammonia and nitrite in the water.