Pre-seeded cycle just stopped

[Britty]

Hi

3 weeks ago I set up a 6 gallon tank for my wife because she would like to keep a male betta.

I bought a 2L/min air pump and a small sponge filter suitable for up to 20 gallons. I also had 30ml of 25% pure ammonia left over from my original tank fishless cycle which I could use for the betta tank. Had pre scrubbed the new tank with hot water. Turned the water temp up to 27'C to accelerate.

As I already have a well established tank I was able to get some bb established sponge material which I wedged in behind the sponge of the sponge filter. I also inserted a small amount of my pre-seeded Matrix into the centre core of the filter. I moved a small scoopful of gravel into the new tank as well.

The filter was working great and the water went cloudy into bloom pretty much within 24 hours. Within 48 hours I was reading nitrites and by weeks end the nitrites fell to zero. I thought at this point I was close to the full cycle being at its end. But in that time my original 2ppm ammonia dose fell to 1ppm and then just stopped, hard.

I just left it for another week thinking it was a minor glitch. It just stayed at 1ppm. No movement at all. Checked the levels daily. Nitrates stayed at 5ppm which indicated no more conversion of nitrites from the ammonia.

Tried a part water change at the start of the 3rd week to try and re-kick start, redosed to 2ppm. One week later as of yesterday it's still 2ppm. No movement at all.

I'm confused and a bit disappointed. I can only assume the original seeded bb colony have died. The tank was always covered, no soaps or detergents got anywhere near it. Water and water changes were always conditioned and I've always been clean working around it and in all I never really interfered with the water in the first 2 weeks anyway.

Anyone have any ideas, or faced this with trying to pre seed a new tank? I'm kind of at a loss other than re-seeding it with more media from my main tank and starting again?

 

[wildroseofky]

Check you PH. It often drops suddenly towards the end of a cycle. You need a PH of at least 6.8 to keep the bacteria going. It slows down below that and dies completely when the PH drops to 6. You can get it back up with frequent water changes or doing a major water change and adding buffers to help it stay up. You can add eggshells, calcium tablets, crushed coral, cuttlefish bone, seashells, oyster shell, or antacid tablets like Tums. Adding a little baking soda will raise it too. That will only last for about 3-4 days though and will have to be checked often to keep the PH stable.

 

[Britty]

Check you PH. It often drops suddenly towards the end of a cycle. You need a PH of at least 6.8 to keep the bacteria going. It slows down below that and dies completely when the PH drops to 6. You can get it back up with frequent water changes or doing a major water change and adding buffers to help it stay up. You can add eggshells, calcium tablets, crushed coral, cuttlefish bone, seashells, oyster shell, or antacid tablets like Tums. Adding a little baking soda will raise it too. That will only last for about 3-4 days though and will have to be checked often to keep the PH stable.

Thanks. I forgot to mention in my post that my PH was around 7.4 and still is.

 

[jlk]

Thanks. I forgot to mention in my post that my PH was around 7.4 and still is.

7.4 on the high range test? This means your ph may be 7.4 or it may be any number below 7.4.

My suggestion is a 90% wc and only add enough ammonia to bring your level to 1ppm. Then rinse and squeeze your cycled tank media into some tank water and pour this dirty water into the new tank. You can repeat this every other/every few days. I would also double check your tank temperature with a thermometer. It's possible that the heater may not be working correctly and it's either very high or very low. Hope this helps!

 

[Britty]

7.4 on the high range test? This means your ph may be 7.4 or it may be any number below 7.4.

My suggestion is a 90% wc and only add enough ammonia to bring your level to 1ppm. Then rinse and squeeze your cycled tank media into some tank water and pour this dirty water into the new tank. You can repeat this every other/every few days. I would also double check your tank temperature with a thermometer. It's possible that the heater may not be working correctly and it's either very high or very low. Hope this helps!

7.4 on the low range. Its not as blue as the reading for 7.6 on the API test, but its bluer than the 7.2, so I picked 7.4 as the mid range.

Thanks for the advice. I'd essentially be starting again by the sounds of it. I'll check the temp with a different thermometer. I'm annoyed because as far as I can determine there was no real reason for the cycle to just stop completely after a great start.

Without knowing definitively why it did, I'm concerned that I'll redo it all and it could stop again and still not know why.

 

[Britty]

Well I started this again. Two days ago I did a big wc and seeded a little bit more bio established Matrix and filter floss into the Betta tank sponge filter and added 2ppm ammonia. This morning did some tests and ammo was down to close to 1ppm and nitrites have just started colouring the test tube, less than 0.25ppm.

*fingers crossed*