My Professor wearing:
3 Leaf Cat card = 30% water resist
Great Old Hauberk = 10% water resist
Vigilante Shield = 10% water resist
Great Old Cloak = 10% water resist
Glorious Ring = 10% water resist
Ice Ring Card = 15% water resist
+10 Tidal Shoes = 5% water resist
Hard Scale on +10 Tidal Shoes = 10% water resist

Should be total of 100% water resist, but only shows 90% when uses @playerstate elemental water.
Test to unequipped +10 Tidal Shoes w/ Hard Scale and Ice ring card, @playerstate elemental water shows 70% water resist.
Also tested wearing +10 Tidal Shoes w/ Hard Scale alone, and @playerstate elemental neutral shows 0%.