Do I need an ammonia source to finish cycle?

[Scoot]

I started my 75g with 6 damsels (lost one right off due to fin injury), ammonia spiked after about a week, moved them out to QT tank. Since then (3 weeks later), the ammonia part of the cycle has completed and nitrites are climbing rapidly.

Ammonia officially hit zero yesterday, after 4 weeks since the start.

I don't have anything in the tank now to produce much ammonia - 4 small LR pieces, and live sand, and a whole bunch of diatoms or something covering everything.

Should I consider an external source of ammonia, to keep the first stage bacteria alive and well, or is what I've got in there sufficient?

[tecwzrd]

Depends on how high your nh3 was when it spiked. If less then 2 ppm I’d be a little leery of adding the fish back once your no2 level gets down to 0. The fishless cycle article goes into more detail.

If your nh3 never rose beyond 2 ppm and since you have a small amount of lr you might want to add one or two cocktail sized raw shrimp to the tank so the bacterial colony can build up more. Especially with 5 damsels going back in.

Lastly I assume you had planned to use the damsels to cycle the tank. They are hardy fish but it’s still considered fairly inhumane due to the toxic levels that a tank goes through during cycling.

Were you going to keep them after the cycle? They get quite aggressive when they mature depending on the species and adding new tank mates will prove problematic.

If they are all Blue Green Reef Chromis then I’d keep them, otherwise I’d consider returning them to the lfs.

Are you doing 20% PWC on the qt tank as needed to keep nh3/no2 at 0?

[Scoot]

Yes, I started with damsels, but removed them after about 2 weeks when they showed signs of stress.

I put them in a small 10g tank, and they were find with a daily PWC, making sure to vacuum up waste from the bottom each time.

I kept a close eye on ammonia and nitrites, and kept everything under control. They seemed quite happy, the water was clear, and they had good appetites (although I fed them very sparingly, being in such a small tank).

Lost 4 of the 5, just out of the blue, today.

I think something might have gotten into the tank - they were perfectly fine this morning, active, alert, swimming normally at all levels. I checked 10 minutes ago and 4 of them were dead. I did a 50% change, then another 10 minutes later, and the one remaining damsel is back to being active.

No clue what happened. Whatever it was it happened fast. I know chemistry in small tanks can change quickly.

Having a small cermony in a bit up for the kids, who are a little upset.

Back to the big tank.

Nitrate was around 2-4 when ammonia was at its peak, and starting to decline.

The fish won't go back in the big tank until both ammonia and nitrites are at zero.

The one that's left (blue damsel) hasn't been too aggressive towards the others, I might give it a shot with him whenever we get other fish, to see how he gets along.

I'll go get a couple shrimp from the grocery store, I figured I needed something to keep the ammonia-eating bacteria going.

[tecwzrd]

So was your nh3 (ammonia) ever > 2 ppm? If so you may not need the shrimp. Sorry you lost 4 more. Are you mixing your sw for at least 8 hours and preferably 24 hours with a ph and matching the tank temp before adding?

[Scoot]

Oh yeah, ammonia was around 20 during peak . My test only goes up to 8, so I used 1/5th tank water, 4/5th tap (with zero ammonia), and got 4.0 to 8.0 readings (hence 4.0 x 5 = 20), just a very rough estimate, but consistently around 20 is what came out of the calculation.

Yeah, pre-mixing water about 12 hours ahead of time, treating with dechlorinator and religiously checking pH and salinity. Used a digital thermometer (with 1/100's of a dgree) to match temps with 0.10 degrees.

Maybe I had a bad batch... the risk of doing daily PWCs.

[tecwzrd]

With that high of a peak for nh3 I wouldn’t worry about adding a shrimp. I see why you had to move the fish. Could be because you did the 50% change, then another 10 minutes later on the qt tank which is kind of drastic but damsels are usually pretty tolerant to large water changes if done at least a couple of hours apart.

I’d just wait for your no2 to spike and then get to 0, then do as many pwc on the big tank until your no3 is 10 ppm or less.

[Scoot]

QT tank:

I've been doing about a third every day for two weeks, no signs of stress.

The 50% change was after the 4 of them died, then another shortly 50% after that (trying to save the 4th guy - he's fine after a COMPLETE change, with about 20 minutes of drip acclimation). He started stressing awhile ago. The water got really cloudy today, and smelled a bit like sulfer.

I noticed when I drained the tank there was a VERY strong sulfer smell. Like the little filter I have in there (foam and charcoal, air-powered) wasn't doing something right.

I rinsed out the couple decorations (letting them dry) before I put them back in.

Washed the tank out with a little freshwater, filled it up a bit with pre-mixed PWC water, then dumped that and basically have a new tank here.

I'm going to run out and get a small HOB power filter, instead of this stupid foam/charcoal/bubble thing. The cartidge in it smelled awful. Could just need a new one, but I want something more powerful.

I want a QT tank that can actually sustain life Then I'll get a cycle going in it when the big tank is all set in a week or two. Should be easy using water and maybe a bit of sand from the big tank.