Miracle mud. Keep or replace revisited

[JOEYRM7]

It's been a while since I have seen the Miracle Mud question. I have a mixed SPS, LPS tank which is now 2 years old. I run Gfo to reduce phosphate and grow Chaeto in the refugium. nitrates run between 2-4 ppm. Whats the current thought process? Replace the MM or eliminate it all together.? I know that many will say that if its not broken, don't fix it, but I wouldn't call my efforts overly successful. Yes many sps grow fine but then again, others have not.

all of my levels are consists t and on target.

So replace or not?

also, between chambers tgere us an area containing bio balls. Should i replace this with rock rubble?


Thanks