Hows the tank doing today?
Did I miss what type of test kit you were useing?
Also to comment on the water changes. Becareful if you do a couple 20 gal on a 55 with in a day, yes you will get your level lower but you have to watch out for your salinity now(water temp effects your Salinity, also you need a few hours of mixing the water to get an accurate reading) if you do to much water changing you can run the risk of "re-cycling"(shocking) your tank. your tank is/was/ should be stable but if you change to much you run the risk of counter acting what your tank needs to do some on its own. RO/DI water will help to reduce this risk some.
on a side note if your by Ec I have alot of nitrate sponge up here that I have never used. I buy things at random from time to time when prices are good
