Water paremeters and upsizing

I just bought an aquarium off a guy who was unable to care for it any more. I am having a few issues and hoping to get some advice.



About the tank...

30 gallons, 28lb live rock, 1 black clown 3", 1 frogfish 1.5", big 3" crab, small 2" urchin, and 1 four stripe damsel. Currently running off a 180gal canister filter due to sump cracking in the move.



Water test results...

HR PH 8.2

Ammonia 0PPM

Nitrite 0PPM

Nitrate 80PPM!??



I know in the move the sand got pretty stirred up but with everything else coming out fine could this be accurate? I tested the nitrate twice and once with a different test. Still same result.



Also once we have the sump tank replaced/fixed we will be moving this all over to my 75gal flat back hex tank. The question is should i even keep the sand in this tank when i switch them? It is pretty nasty from the guy not taking care of it, but what do you guys think?



Thanks guys!