not sure what's wrong

[fonze]

I have a juwel Rio 125l running 2 filters a fluval u2 internal filter rated to 110l and an aquis cf 500 external rated to 120l. On Friday the aquis stopped working and I repaired it asap and since then the fish have been behaving odd their gill movement is more rapid than normal and some of them have started to flick and rub unfortunately one of them died. I have treated for velvet on Saturday but they are still doing the same and I'm not sure what else to do. They don't have any visible signs of white spot so I am at a loss. Please help if you can.

 

[LyndaB]

What are your readings for ammonia, nitrite, nitrate and pH?

 

[fonze]

Amonia 0 nitrites 0 nitrate 10 (tap water is ten) ph 7.2