Septic tank core sampler

Is it worth the investment to buy a core sampler?
My home built in 74.
3 bed 2 1/2 bath home.
Concrete septic tank.
I had new risers and everything inspected and pump 3 years ago all good.
I check yesterday with 2x4 mark for every foot.
At entrance lid.
3 feet from bottom of tank to top foam layer.
Another roughly 6 inches intake pipe to top of foam.
Based on feel roughly 6 inches of sludge at bottom
Read 25 to 33% sludge have pump.

Is core sampler rentable tool?
Online $120 to $170.
I tried to piece parts on amazon but i was suprized clear pvc was $50 for 8 ft.
Id hate to gather parts and not come out working and wish i would have bought one made up.
If i plan on staying in the home for atleast 8 more years possibly 15 years i dont think be bad tool to have.

What is everyone's thoughts?
Thank you for any inputs.