I have talked to Sarellia, received the glow stone and also received a second golw stone from a locked chest. My problem is the sewer gate will not open and I have tried the glow stone on it, also I haved tried to ask Sarellia every question numerous times not to mention "I'm Drowning" :I. Can anybody help, what am I doing wrong.

Well - that really doesn't tell me where you are. There is one gate that I recall not being able to open. You could see a mermaid on the far side of the gate. There was another way around to where she is.
Have you been through the rotating room??



Keep looking for air pockets. They are all over the city so you can catch your breath.

The trigger word for Sarellia is "Oracle" - she should have given you the first glowstone and opened the floor grate.

Sometimes if you're standing on the grate when she tries to open it for you it won't swing up. Try clicking on the front edge.