Set up Q-See QT5816 for remote access

I had to replace an older QC-series DVR with a new QT5816.  I'm having a lot of trouble getting web access to see the cameras.  The older system provided web-based monitoring with no troubles.
Here is the setup:

Zyxel ADSL Modem at 192.168.0.1 with a static public address - so no need for DynDNS.
QT5816 at 192.168.0.2 (static)

I have tried using only UPnP but the modem didn't seem to hold the settings.
I have the QT5816 http port set to 85 and the standard data port of 6036.
The modem seemed to drop the port 85 setting in UPnP.

The original used port 80 and I'm not sure if it used UPnP mode or Port forwarding.

Next I tried port forwarding 85 and 6036.
Some things work and some things don't work.
Super Cam works on my iPhone.

addressing the dvr at the modem's static public address plus :85 ends up with
[ipaddress]:85\WebClient.html  (no http://)
Some browsers work and some don't.
Some only want to search and not just go to the address.... etc.

I need to make this work reliably.

Update:  I've attached a diagram just to make things clear.
I have changed the HTTP port to 80 and have forwarded it in the modem/router to the camera DVR.
This seems to work more reliably but I'm getting reports that phone monitoring is flaky.
Analog-Camera-Network-Diagram.pdf