Keep No3... more fish, less carbon dosing, or amonium ?

[Patx]

Hello,
my No3 are often down or "stable because"
I try to keep it between 5-15ppm.

I've added more fish than I've ever had. but it's still not enough.
So i just feed more pellet.

I have an automatic feeder that pours 0.5gram of sinking pellet to the point where most of the time...the fish ignore it
I also manually feed 1x/day about 1x1inch of a scallop/selcon/vitachem mix (the fish eat it all)

- I change my filter socks 1x/week.

I have another tank "refugium/holding tank" connected with lots of Xenia and cheato that I keep at a baseball size.

~15gallons

I dose:
+0.04ppm of Kh2po4 /day
my Po4 varies from 0.05 to 0.1

- 2ml of bacto balance.

-10% water changes per week.

I feel like adding unconsumed pellets will in the long run add unnecessary pollution. (what do you think?)

if I ever cut the pellet dose I have to reduce the consumption of No3 or dose some.

The choices i see:
-reduce the dose of bacto-balance (but I like it because it adds a bit of trace elements).
-reduce the light intensity in the refuge
(how much do the Xenia consume? Are they ?)
- add more fish
- dose amonium
- do nothing.

55gallons total system.
24x24x18 tank (~40 gallons)

1-royal gramma
1- yellow wrass
1- tail spot blenny
1- diamond goby
1-clown
2-firefish

Thk