aquarium keepers

[flybyferns]

Any tips on how to get the rest of this substrate out ?
I am not planning on replacing it.
I removed 99% over the past - several - water changes. ( of which I do weekly--maybe the past 6 weeks or so )
I'm running 2 very well cycled / well stocked fluval 405s - I believe this is 75 gallons. ( I know ----overkill , but I have them ...might as well use them)

The only 2 products every used in this tank is stress coat and tetra black water.
The yellow/orange discus are 5 years old and the blue one is and old man -he's 8.

The typical water parameters did not budge during this....I have not rinsed ( seldomly do and never change ) the sponge filters; I though I'd wait a bit longer?




Thanks