newbie fishless cycling - please help!

[Paul G]

Hello all, would be really grateful for advice as to where to go from here.

Tank is an AquaNano 60/100 - so it's 100L, with the stock pump and lights etc. Some aquatic compost substrate covered by sand, a few plants but not heavily planted. We're 5 weeks into fishless cycling, as per the guide on here, and things seemed to be going well until just recently. We had the ammonia phase and then the nitrite phase, but then the nitrites suddenly dropped to zero like they should, and for about a week we were dosing up to 4ppm ammonia and this would drop to zero within 24 hours with no nitrites detectable at all, so everything seemed to be looking good. We're using the API master liquid test kit.

So on 30/10/15 we did the 80-90% water change, as nitrates were very high at 120ppm. Also added in some bogwood which had been soaking in a bucket for 4 weeks. Following this I may have made a mistake: we knew it would be a few days before we could get our fish so we dosed up to 4ppm again, and things seem to have stalled a bit. It took 2 days for the ammonia to drop to 0.5. I discovered that our KH was very low at 36 (having been 54 earlier in the cycle), and the pH swung a bit - it had been 7.6 consistently throughout the first 4 weeks, was then 8.2 immediately after the water change (the same as out tap water), but then quickly dropped to 6.8. Thinking that the low KH and dropping pH might be a problem I added some sodium bicarbonate, and now pH seems stable at 7.4, and the KH is better at 71.6. But today, after dosing a little more ammonia yesterday (up to 3ppm), we're seeing nitrites again for the first time in a week (0.5ppm), and ammonia today is also 0.5.

I don't really want to put fish in with the current readings, but am I being over cautious? Do I just need to dose less ammonia until we get the fish, and go ahead anyway, or wait a few days and see if the cycle re-establishes fully? Could the big water change, or adding the bogwood, have messed things up? The nitrates are already climbing a bit (40ppm) so I probably need to do another significant water change before I add the fish (there's some nitrate in our tap water).

Any thoughts would be gratefully received, our daughter has been so patient so far but she's starting to worry the fish will never come.

Many thanks,
Paul

 

[ScotJudd]

Hi there.
There are a lot of variables in your dilemma.
Increasing the Kh to maintain a stable Ph is a good move. The bog wood would tend to drive Ph down and the Bicarbonate will stop this happening
You say you have nitrates in the tap water, at what level, hopefully less than 10ppm. Diluting nitrates in a tank with source water with nitrates will not help matters.
What now? I would reduce your nitrates to about 20ppm if this is possible. Raise ammonia to 2ppm. Wait 24 hrs. If ammonia is not at zero and nitrites are not at zero then you are not cycled. Keep the nitrates fairly low and reset ammonia daily to 2ppm. Note I say reset ammonia to 2ppm not add 2ppm ammonia to further raise it.
Temperatures just above 80f are known to help increase cycling.
You obviously have a cycle because large nitrates are being formed but it might not yet be robust enough. Keep at it and be patient.
Respect to you for keeping your daughter from 'persuading ' you to buy fish. I have daughters and grandchildren and they just can't seem to appreciate the need for the empty tank for so long ?.


Sent from my iPad in West Yorkshire, U.K.

 

[Paul G]

Thanks very much indeed for that, we'll keep plugging away. I'll test the tap water nitrates again tomorrow - I think it was pretty low but can't remember the exact value. Large (80-90%) water change dropped the nitrate from 120 to 10 so I guess it's not a big problem.

Our 6 year old daughter spent 2 straight hours captivated by the fish tank at her cousins house... It'll all be worth it in the end I'm sure.

 

[Fel]

I just finished cycling a 10 gallon this week and pretty much the same think happened to me.
Thought it was cycled did a water changes and put some plants in (this was a coincidence) and went to test again. Long story short it took another three weeks for it to cycle. It's worth noting that I was cycling the tank at a pH of 6.8 or so which is probably why it took so long.

I'd say just keep going with the cycling, the worst thing that happens if you wait is your tank spends some more time empty. If you add fish then something bad can actually happen.

Sent from my HTC6515LVW using Tapatalk

 

[Paul G]

So we did a partial water change last night and dosed ammonia up to 2ppm, nitrates were down to 20 after the pwc; tonight all looks good with 0 ammonia, 0 nitrites, and nitrates between 20 and 40. PH is stable at 7.4. (Turns out our tap water has <5 nitrates.)

So I think we're cycled? Just done another 20% water change to lower the nitrates a bit more, dosed a tiny drop of ammonia, and I reckon we should be OK to put fish in tomorrow as long as ammonia is 0 and nitrates 20 or less in the morning, does that sound right?

Very exciting...

 

[Mebbid]

That sounds perfect to me !

 

[Paul G]

Great, thanks for the responses. We came back from the fish shop with 8 neon tetras, 4 zebra danios, and a Japonica Amano shrimp (we think this is around 50% stocked - 100L tank) All the fish look great, quite active, bright colours on the tetras, all water parameters still looking fine after >24 hours, we'll continue to watch them carefully.

Unfortunately the shrimp seems to have disappeared, we're hoping he's hiding under the bogwood, but we're a bit worried he might have climbed up one of the tall plants and jumped out - there's a tiny gap around the edge of the lid...

Really enjoying watching the fish at last, after 5 and a half weeks of cycling!