Fishless cycle help

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Jacob Reed

Registered Member
Original poster
Jan 25, 2019
Hello all,

I'm new to the forum and new to the aquarium fun. And I need some advice regarding my apparently stalled fishless cycle.

I got a new 36 gallon tank 4 weeks ago and seeded the tank with filter media from my established 10 gallon tank and dosed (2ppm) with Dr. Tim's ammonia. The cycle started immediately and was consuming .5ppm of ammonia daily but after just 5 days, the cycle stalled and ammonia stopped falling. That's when I noticed a chemically smell (like faint burning rubber) coming from the water. A few days later (ammonia still not dropping), I decided some of the fake ornaments, gravel, etc might not have been rinsed well (causing that smell) and maybe some chemical on them killed the beneficial bacterial.

So I did a 90% water change, put in API stresscoat+ (as the water conditioner), waited 24 hours, dosed with ammonia (2ppm) and added Tetra Safe Start. A week later, the ammonia started to drop, but then stalled again.

I noticed the PH was quite high (8.6 - my tap is 7.4), so I used chemicals to lower the PH to 7.6 (I know I probably shouldn't have now).

Anyway, it's been 3 weeks since I used the TSS and although ammonia was dropping about 10 days ago, it's not now. Right now, ammonia is 2ppm, nitrites 0ppm, nitrates 2ppm, PH 7.8. temperature 81°.

So, how should I proceed? Should I do another water change (I can still faintly smell that chemical? Get more TSS? Our should I just be more patient and keep waiting?

I'm anxious to get my fish in there!

Thank you for the help!!


AC Members
Jun 28, 2006
SF Bay area, CA
Yes, I would do a big water change (50% or more) & test again. You're getting close...but not quite there yet...keep it up!.

It can take 6+ weeks to cycle a tank...patience!!
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Global Moderator
Staff member
Jan 11, 2013
West Falls NY
Real Name
Welcome Jacob! Just to back up a bit, once you set this new tank up with established filtration media, I would have stocked it right away with a bio load similar to what it had in the 10g. That's the whole reason to use seeded media.

I've never used Dr Tims or API's stress coat. I'd get a good dechlor product like Seachem Prime and you've already got water test kit which is great.

Like fishorama suggested, change a bunch of water. Retest for no ammonia and nitrite and stock the tank. Feed lightly and monitor water parameters often until you know the tank produces nothing but nitrate. Then get a feel for your nitrate creep over the course of 7days and gear your weekly water change to keep nitrate no more than 20ppm on day 7.


...and over the edge.
Staff member
Dec 30, 2005
Real Name
Mr. Normal
And unless you have some specialized need, leave the pH adjustments alone. Also, a GH/KH test would be nice, tap and tank.
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