Shower tray leak

[John.Stitch]

I reinstalled this corner shower tray last year using backer board and tiles. When I re-tiled I grouted the shower tray-tile joint which leaked.
The door frames are sealed with silicon with the joint on the walls.

So I removed as much grout from these joints and applied silicon to seal in February.

I have a leak (slow drip) at either wall corner of the tray, the water drips down the joint with outside of the tray and the tile. I looked under the tray as best I could and it looks like these are the only two points of leakage.

So I am trying to establish the source of the leak.
1. Silicon not sealed the tiles and the tray so add more silicon?
2. Silicon not sealed the tiles and the tray so remove bottom layer of tiles and redo?
3. Water is absorbed by the grouting between the wall tiles and working its way downwards. But I thought grouting would be ok on the walls?


And a supplementary question, what is the best way of removing scale from this tray, the manufactuerers recommend CIF and not to use abrasives or vinegar.I tried CIF but it does shift it but very slowly.

Couple of pics:

http://img97.imageshack.us/img97/2679/p1000409yn.jpg
http://img16.imageshack.us/img16/1017/p1000410r.jpg

 

[denso13]

Remember to seal the tray/wall joint with silicone before you fit the enclosure frame to the wall. If you don't you will get leaks at both corners as the water works its way down the frame.