Well, 75 degree water temp wouldn't be too bad, but it would be recommended to bump that up to about 78-80. Also, an ambient air temperature of about 85 and a basking temperature of about 95-100 would be more appropriate. However, you want to make sure that the basking area would have a good gradient so that obviously the further away from the spot he moves, the lower the temperature. This allows him to choose which temperature is more suitable for him at the moment.
As far as feeding is concerned, 3 times a week approximately, depending the size of the previous meal. I wouldn't feed him a LARGE meal each time. It's great that you are feeding it rodents, but you can't forget variety. Variety is key in proper diet of crocodilians. Fish (be careful to make sure that you aren't feeding fish that contain high amounts of thiaminase), chicken chunks (supplement with vitamin supplements), beef chunks (supplement), or....you might want to consider purchasing a commercial croc diet such as Mazuri (www.mazuri.com). There are other things that can be fed beyond what is listed, but for the sake of keeping this shorter, I will direct you to some further reading as there is much more to their husbandry than diet alone and what is attributed to it.
Here are some resources for you to read up on for crocodilian captive care.
My website: http://www.herpfanatic.com/Crocodilians and the Private Keeper.htm
Chris Dieter's website:
http://www.thecrocodileexperience.com
Israel Dupont's Crocodilian Directory:
http://www.crocodopolis.net
Adam Britton's Crocodilian Captive Care FAQ:
http://www.crocodilian.com/crocfaq
Books:
The Ultimate Guide to Crocodilians in Captivity by Chris Dieter
Crocodiles: Biology, Husbandry and Diseases by FW Huchzermeyer
Crocodilians: Their Natural History and Captive Husbandry by Ludwig Trutnau and Ralf Sommerlad
Crocodiles Inside Out: A Guide to the crocodiles and their functional Morphology by Richardson, Webb and Manolis
I hope that helps.
Chris
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My Website
www.herpfanatic.com