HEY little grey friend ! .. Thanks thats great PH info there ,i think i may have read it before ?.Was it one of JM's ?. PH the manual ... very handy to have on here now :smokebuds:easy refferance,cheers ...... so ,if i put in 6.4 & got 7.2 (diff. 8) - 7.2 +.8=8 ? . if thats right should i flush with lower PH?. say 5.5 or 6.0 ? ph 8 sounds bad ?..thanks for looking in G