Salinity

[corper]

When I top up the tank with fresh water, I've been adding 5 gallons over 45 min. The tank is 72 gallons with a 33 gallon sump. The salinity changes from 1.028 to 1.025. Is this too fast? Also, I didn't set the tank salinity that high, I just never got a chance to top off last weekend. My salinity is usually at 1.024. My reason for keeping it lower than 1.026 is so that if I don't get a chance to top of right away the salinity won't go through the roof! Thanks for the help.