Borates in high doses have caused testicular atrophy and low sperm count in male dogs and fetal reabsorption in pregnant *******. The doses were far higher than what's in your pool but chronic exposure to small amounts will affect liver and kidneys eventually.
It is not always easy to teach a dog not to drink from the pool or any other body of non-potable water. If you correct her while she's in the pool drinking, she may well associate the correction with the pool itself and become scared of it. We recommend you place two dishes of water several feet apart near the pool. Fill one with pool water, the other with her regular drinking water. Have some tiny treats handy. Microwaved quarters of sliced turkey dogs are good, esp. the low salt variety.
Put her on lead, guide her to the fresh water, praise as soon as she makes a motion to sniff it or drink it (Good water! Good dog!), give a treat. Verbal praise should be done with a slightly high pitched voice. Guide her to the pool water dish and give a verbal and physical correction. The verbal correction might be a strong NO (using a low voice), or a PFUI. The physical correction would be a pop on the lead straight up.
Then switch back to the fresh water dish, lots of praise, lots of treats. Do not let her in the pool that day. This training session is strictly for her to learn that fresh water is good, but the smell of pool water is bad. You can do water training sessions twice a day and keep them short because she's still young with a short attention span.
When you do allow her in the pool and she begins to lap, use the same verbal correction you used for the bad water dish, same voice, same word. She'll catch your drift. As soon as she stops lapping, if only to look at you like 'What's up?' give verbal praise.
Anna