using a reactor question

[Moorepower]

ok might sound stupid but is there any problems if i use a phos reactor with like phoslock and use bio pellets? i have a phos problem and a small nitrate problem. phos is about .64 and nitrate is between 10-15. i have tried a lot to deal with phos with no luck i think its leaching from my rocks but i do not want to take them out and try and scrub them. so i thought a reactor will help and i can just try and blast them with a turkey baster. any ideas?

im thinking people will say dont mix just run phoslock in it. never seen anyone asking about mixing the 2 so thats why i thought i would ask.

also my tank is a 75 gallon with 29 gallon sump. never had a phos problem before so this is new to me.

and i was looking at 2 reactors one was the phos150 upto 150 gallons and phos550 upto 600 gallons. i know the 150 would be fine but would it be bad to buy the 550? i looked and the operating flow rate andtheyare the same.

any help would be welcome thanks