Fishless cycle seems to be stuck at 0.25ppm ammonia!! HELP

[JadeHB]

Hi everyone,

I started fishless cycling my tank about 6 weeks ago. I used tap safe and filter boost bacteria to kick start the cycle then fed the tank with fish flakes. My ammonia was reading 4.00ppm about 2 weeks ago then I was advised to do a water change by a FB group as wasn’t coming down but nitrites were zero and Nitrates were high? (60-80ppm) since the water change it’s been stuck at 0.25! I was advised to dose the tank with more ammonia to see if it cycled it out within 24 hours so added more flakes to break down but it’s not even managing to cycle the 0.25 so there’s no chance it’s going to be able to cope with more from what I can see? I even added more bacteria! What have I done wrong? TIA

 

[Aiken Drum]

Check your ammonia test against some bottled water that will be 0ppm ammonia. 0ppm can sometimes look like 0.25ppm on an API liquid test.

I would also check your tap water to make sure you arent adding in ammonia when you do a water change.

I dont like using fish food as a method of dosing ammonia as you have no idea what your ammonia starting point is. The idea is to cycle out 2ppm in 24 hours.

 

[JadeHB]

Ok I’ve checked the tap water and that’s zero! I wish I had got liquid Ammonia now looking back and how tiresome this is becoming lol we just went our fish! I just don’t understand how it’s not managing to cycle out the 0.25? Is it just a waiting game until it’s zero? And should I keep feeding the tank flakes?x

 

[Aiken Drum]

Yes its a waiting game. A fishless cycle typically takes 6 weeks, sometimes quicker, often much longer. This assumes a steady supply of ammonia of 1 to 2 ppm concentration. Without knowing your ammonia from 24h earlier there is no way of knowing how far along you are with your cycle. My guess would be its pretty good because you arent seeing much ammonia, no nitrite and nitrate is quite high (or at least was high before your water changes).

In reality, unless your pH is pretty high then 0.25ppm ammonia is pretty safe for fish. The ammonia is still a sign your cycle isnt complete, but not too much to worry about

Its up to you how to proceed.

You could continue with your fishless cycle and wait it out. Continue putting fish food in daily or get some ammonia (or better still ammonium chloride) and wait until you see 0ppm.

Or, do a big water change, make sure you get all the waste food out and finish off your cycle with fish. Add a few fish, test daily, do water changes as needed to keep your water parameters safe (ammonia + nitrite combined below 0.5ppm) until the cycle is established for those fish and then add some more. Rinse and repeat until fully stocked. As per my comment above, i think you must have some cycle going so this should be a safe route if you don't go overboard on your stocking to start with. Its certainly safer than doing a fish in cycle from scratch which in itself is perfectly safe if done properly.

 

[JadeHB]

My PH is 7.6, and the nitrates are still high even after the water change this was what was confusing me aswell�� it removed nothing I did 50% twice! It did remove the ammonia and dropped it to 0.25 and now stuck at that! I had no idea what an undertaking this would be! But it’s not rising so it must be doing something as there is still decaying food in the tank. I think I will wait it out another week, see if reaches zero and if not and still on 0.25 I may do a 90% water change, add fish and try to get it to balance it out! Thank u so much for your time!

 

[Aiken Drum]

Have you tested your nitrate immediately before and after your water change? It should drop by half after a 50% water change. It going back up afterwards as the ammonia cycles out is normal and it will go up by more than ammonia goes down. Every 1ppm ammonia converts to 2.7ppm nitrite and that converts to 3.6ppm nitrate.

 

[Aiken Drum]

Also, tank temp of 83f (28c) is optimum for bacteria growth. Remember to reset it suitable for whatever fish you plan before stocking.