Height of shower tray with saniflo

[rolo]

Hi all,I'm new to this forum and am hoping someone can give me a definitive answer on a problem.
I have built an en-suite shower/toilet room and have employed a local plumber to instal all the incoming pipework and leave ready for the final connections to the appliances by myself. The drainage is by a sanipro unit and reading the instruction booklet it states the shower tray must be a minimum of 120mm from the floor,which I have done and the tray is now fixed and tiled up to.
However I have subsequently noted the diagram supplement that came with the sanipro states minimum 185 mm !! ,reading back through the booklet all the other language sections state 180mm...only the UK section says 120mm!!!
I am now concerned that the tray is too low...although i'tll be a pain to raise I'd rather get it right now and avoid any future problems....(like sewage backing up into the tray?).
Saniflo have been no help and wont give a definate answer on the correct height so any help from you guys based on previous experience would be really,really appreciated,as I've kinda lost my enthusiasm for a project that was previously going really well.

 

[WHPES]

Is there really no way you can get the pipes to the soil stack without using one of those dreadful devices?

 

[stevetheplumber]

120 sounds plenty to me the saniflow has a nrv built in so shouldnt back flow

 

[rolo]

No,next to impossible to get a waste to the stack without major upheaval....are they really that bad?,my plumber seemed to think it was a good option.

By the way the tray is right next to the saniflo and there is a fall of about 3 cm on about 600mm of waste.