well it seems it does cause a problem, got back last night and most of the leaves had fallen off and had gone all sloppy and were all over the place, so i scooped it out and chucked it in the bin, so i advise no one to buy it, though it does look nice. its only been in there 2 weeks
i did a little reaserch and bought some propper aquatic plants off ebay today, so hopefully they will be here soon and i can re plant it.
it does offer the question though why aquatic shops sell stuff that arnt meant to go in tanks, and why they just seem to sell you stuff without asking what tank you have, seems from now on im going to research before getting anything else.