Is My Tank Having Too Much Free Ammonia?, Not sure about levels tolerated by goldfish Options

[2goldfish]

I have a new tub setup, roughly 70cm(L)x52cm(W)x30cm(D). It has been running for 11 days, 1st four days no fish, then a few small GFs(3) when I thought the cycling had completed (using old tank water).

I added in 3 more (1-1.5inch GFs) as I thought tub should be able to handle?

Two days ago, I bought some anti-ammonia rock (zeolites?) as my Seachem indicator has been reading green since day one. Changed water after 1 week and put it in but no reduction in ammonia as its still at the 'green' colour level (0.05mg/l) free ammonia.

Today, after I put in those 3 layered (coarse, charcoal, fine) combo media with ceramic rings sandwiched inside, the water was getting very cloudy after I repositioned the zeolite, threw out the old OHF filter media but kept the ceramic rings.

I STILL have been getting the same reading...but water has turned clearer by this evening. However, few days ago, the fish were all huddled together at the bottom of tub and occasionally dart here and there. This evening as water got clearer, they seem more lively.

Q: Is there a long term risk to expose them at these rates or should I reduce NH4 to below 0.05mg/l?
Going by HappyBuddha's post about NH4 toxicity levels, it should be ok? RG experts, please enlighten me.

Nitrite reading last taken 1 hr ago: 0.3mg/l
PH: 7.5-7.7
KH: 5-6 dkh