We want to take our dogs everywhere with us, so we fully understand people who want to involve their dog in daily life, whenever possible.
Dogs are obviously not the cleanest animals. Sure we give them a bath? but how often? every week? every 2 weeks? If you went 2 weeks without a bath, imagine what you would have on your body?
Actually, many dogs do more harm to the pool just after they have been bathed, since a lot of dog shampoos and grooming products contain agents that already cause problems in pools on their own. This often comes in the form of increasing the phosphate level. Read here
Your dogs will introduce lots of bacteria and other elements into your pool that increase chlorine demand. The pool can handle it, as long as adjustments are made in how much chlorine is being added and how much the filter is being run and backwashed. The main thing that the dog will do is increase the chlorine demand and phosphate level.
If your chlorine reading is just showing above 2.0 PPM, and your dogs are going to swim, or have been swimming, you are likely to have a problem if the pool is not shocked or super chlorinated within a day or two.
Also, consider your other variables in the pool system. Any hair that is shed by the dogs will end up in the water, and eventually the hair will be filtered. Your skimmer basket may catch some of it, but generally, most of it will end up in the filter. If you have a Diatomaceous Earth (DE for short) Filter, you may have to backwash more frequently if the hair is clogging the filter. You may also need to open it up and manually clean the grids more often. Be careful to check your filter pressure throughout the backwash cycle. If you start getting Algae, or when you vac your pool, no matter what you do, you cant get enough suction to clean the dirt and other debris, check your filter.
Most important, the more hair your dog has, the more problems you will encounter. No matter how often you groom, it is always best to simply keep them out of the pool as much as you can.