your right about flushing to remove salts, flush once monthly either with plain phd water or florakleen/clearex....this is highly recommended due to some brands of nutes being saltier than others, for example GH flora is like a salt truck compared to botanicare...these salt build ups can cause PH flux and undesired higher strength solutions. what chiller did you get? i hope you got a chiller for larger tanks than you have, they i believe have BS ads saying they can cool 100gal, i picked up i think a great deal from ebay, polar bears 1/3HP i absolutly love them