Hello again Rebecca and thanks for waiting.
Sorry to hear about Chopper's condition, hopefully it is not that serious. However I have worked out an answer for you, please read it through and see what you think ...
Firstly I have to tell you that this sort of thing is always a gamble so if you want to be 100% sure you are doing the right thing you should have a vet check Chopper over without delay.
Having said that I am aware that there are a number of home remedies for diarrhoea in the dog which some owners use, these often work well in uncomplicated cases where a dog is otherwise quite bright and happy as in your case, where for example a dog has eaten something he should not have out in the yard, or some unaccustomed rich foodstuff, or has a minor tummy bug.
Here are some examples of suitable home remedies.
1. I am aware that some owners use the likes of Pepto-Bismol to treat their dogs with gastro-enteritis and often report success. Here is a link to a web page which has all the information you might need including dose rates : LINK
2. Some owners try and control the situation with diet alone before they try anything else. This is logical and often works, the basis of this is to give the intestinal tract a complete rest and then bring it back slowly to function, resting the alimentary tract is the critical factor. It would go something like this ...
A. Starve him for 24 hours but make sure he has access to water.
B. The next day feed him four or five small light meals in the day. These meals should be the likes of chicken, fish, scrambled egg etc. with a little rice.
C. If he picks up on this diet gradually reintroduce his normal diet over the next few days.
3. Live yogurt added to the food can often help. Some gastro-enteritis situations are caused by an imbalance in the bacteria in your dog's gut. Live yogurt is full of " good " bacteria and will seed them into your dog's intestinal tract and restore the balance. You do not need to give much, perhaps a tablespoonful twice a day.
4. Finally you can reference this web site for additional on the topic : LINK
Of course if any of the above does not quickly start to work or if Chopper deteriorates further in any way you should see your vet without delay just to be on the safe side.
I hope I have given you a few ideas and covered your question fully enough but if you would like further clarification or to talk things over a bit more then I will be on-line for the next hour or so and I will be more than pleased to continue working with you.