Unfortunately the feeder blocks do seem like a good idea but can cause ammonia issues because its no different than adding a weeks worth of your normal feed all at once & we all know that is a bad idea.
Please do another water test & post your readings.
What kind of test kit are you using?
Also please post all your stats, water temp, ph, nitrite, nitrate, ammonia.
Once we have this information then we can hopefully help.
Those stats are promising. Do a 25% water change to get the ammonia down to a reasonable lvl you want 3-4ppm.
The Ph is a bit of a concern, if it goes lower it will crash your cycle, chuck in teaspoon or 2 of bicarbonate of soda, this will raise it to 8 again.