High Nitrates In Tap And Cycle Stuck?

[maurizio]

Day 26 in fishless cycling, I'm stuck with about 200 mg/l of nitrates. I believe the main (only, hopefully) source is the ~50 mg/l from the tap water.

My last attempt to change things was:
I changed 128 l (85%) with unconditioned water. NO3 down to ~75 mg/l (best I could do!! ). Added 5.2 ml of ammonia 8% to continue the cycle.
24 h later, NO3>>100mg/l (offscale, likely again around 200 mg/l), whereas ammonia keeps being eaten completely. Nitrites also appear stuck at around 10 mg/l, likely due to the high nitrates.

So far pH is stable, 7.4 to 7.7.

Solutions?? What I thought, and I don't like any of them:
- I could add demineralized or rain water, but this will mess up with hardness and pH, which is actually perfect in my tap water for my purposes (low-end brackish).
- using a biofilter medium able to help, such as Symbiont. The one I have, however, is Eheim Substrat Pro, and is said to be comparable, so for the moment I won't go this way.
- a complex and expensive NO3 filter, with all the extra risks implied. No way.

How can I possibly complete the cycle??

 

[phocoena]

Nitrates are the natural end product of the cycle, so as long as you are adding ammonia you will be getting nitrates with nowhere for them to go.
Nitrites could be showing that high if they are over the values shown in the chart. as long as nitrate keeps increasing then it is likely the cycle will keep progressing.

Have you actually tested your tap water or are you going on the maximum allowed by your local water board?

 

[maurizio]

Yep, I'm aware of the cycle theory.
However, my impression is that NO3 is peaking insanely well before NO2 has reached its peak, simply because I have so many already in tap water (sure, I measured it. I'm using Tropic Marin tests and the Tetra stripes, which help me where TM goes off chart).

Now, to my knowledge, this high content of NO3 might:
-unbalance the pH
-inhibit further transformation NO2 to NO3
-start an algae bloom (lights are off for now, but soon I might receive the plants I order, which will be in insignificant amount to be of any help with NO3).

Am I wrong, should I just ignore the whole thing, and keep adding ammonia?

 

[Dieses Madchen]

To lower nitrates just to monitor where your cycle is heading, you can use demineralized water, but add a nylon sock full of crushed coral to keep the pH up.

 

[phocoena]

If the ammonia is dropping even if nitrite is not visably dropping then the cycle could be progressing still.

Keep in mind the full picture of the values, Ammonia dropping, Nitrite?, Nitrate rising? will tell more than just the the Nitrate reading on it's own.