Hi I am new to discus keeping and absolutely love these fish, I am posting on here for some general help and hopefully some great minds can help me.

I have had my 4ft tank up and running for 7 weeks now, I started cycling with danios and things were going well till a mate of mine offered to give me his dirty filter sponge to help kick start things along quicker.
I used it in my cannister filter resun 1200 on the 3rd week, and got readings of 2-4ppm ammonia, anyways I also ended up with loads of round worms(nematodes) floating every where in my tank.

The filter media is in the 3rd basket bottom basket Noodles
2nd basket seachem matrix media which was put in on week 4
1st basket has black coarse sponge and fine filter wool on top.

I have been using prime from day 1 and started using seachem stability 2 weeks ago.

week 4- I was given some potassium permegrante to kill them off and I got there (nematodes) numbers down by 90% did a major water change 60%, after that ammonia sat at 1ppm and my discus arrived a bit earlier than wanted they are a 2 year old breeding pair.

Ammonia has spiked up to 4-5pmm not going down.

Week 5-6 the discus laid eggs and now i have young which are thriving.

My ammonia is now at 1-2ppm again after a 50% water change yesterday and a 25% water change today.
My ph was at 5.8 and is at 6- 6.1 now my nitrates are at 10ppm.

I am a bit confused at the moment as to why ammonia still shoots up high ?
I believe my cycle has stopped because I have now read that my ph needs to be at 7- 7.5 to make nitrifying bacteria, is this true?

Will the bacteria still grow on my bio filter with ph 6?
If so when will this cycle finnish? Are nitrates showing up a sign that the tank cycling is almost done?

Kind Regards H