:wa:
if water is clean , then it should be ok take bath in the tub .
a related fatwa :
Do I Need to Make Wudu' after Ghusl ?
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following:
"
If, while taking a shower or bath, you washed/gargled your mouth and rinsed your nostrils then you need not to make a fresh wudu'. Your wudu' is already included in your shower or bathing if you had formulated the intention (niyyah) for the same.
If, however, you did not wash your mouth or rinse your nostrils while having your shower or bath, then you should make wudu'. The reason for this is that washing the mouth and rinsing the nostrils is part of wudu'. Therefore, in case of omitting the same, one should make wudu'.
Likewise, one is advised to make wudu' if after having had a shower or a bath he/she has intentionally touched the private parts."
http://www.islamawareness.net/Ghusl/fatwa_wudu_1.html