Need some help, guys & gals. Moved everything from a 28g into a 50g three weeks ago & have 0 readings for ammonia, nitrite & nitrate. I used the same HOB filter that was on the 29 & added another HOB with seeded filter pad. Why am I not seeing any nitrate? I ve tested every week & it s been the same readings. All the fish & shrimp are happy & healthy. Confused....