Also, I've done two 50% water changes. Yesterday I added a pre-filter and new sponge media to my filter. I left the original cartridge in the filter as well until the new media establishes it's own bacteria.
Last parameters are as follows:
pH: 7.4
Ammonia: 1.0 - 1.5 ish
Nitrite: 0 ppm
Nitrate: 0 ppm
No worries, been there. I’m assuming you have checked tap water for ammonia (or whatever is used for water changes)?
Unfortunately tank cycling is a slow process of a month to two months. Some ideas to go with above posts.
Cycled filter media can be bought in the US. Can’t remember the name but an option.
Products that detoxify ammonia are worth a try. I’ve been very happy with seachem safe for many years. Worse case is it may slow tank cycling slightly generally.
Products that add nitrifying bacteria (bacteria in a bottle) - also worth a try. IMO they have gotten better and rarely cause a problem.
Reducing stocking as you mention and water changes - likely daily unfortunately. I’ve had more lightly stocked tanks go more than that in ammonia so unfortunately from the information the ammonia reading could be possible. On the flip side, once cycled the bacteria get pretty bullet-proof.
I remembered it was api nitra-zorb that I used.
There’s not really a medicine that can help with ammonia damage. I’d have some ideas but they’re risky on your young bacterial population. Watch for secondary bacterial / fungal infections. The water changes will help there.
Make sure water changes are roughly similar temperature within 20% and go for smaller, more changes. That’s not always practical here so I’ve put say a betta in a small container of old water, changed 50 to 100% and then floated him back in the container and acclimatised him. Just in case you need to do a 90% water change for ammonia.