Can I withold the cost of mold testing from my rent

We decided to get a mold test done because we were always getting sick and there has always been a strange smell in the house. I have a young child and she has been sick every month since we moved in. We had a couple of minor repairs that were needed after we moved in like getting the sprinklers repaired and the AC stopped working cause it needed coolant. Anyways the landlord said that we were responsible for paying these expenses even though we had not caused the repairs. He hired an attorney that demanded us to pay for these repairs. We had to hire our own attorney to tell his attorney that he was in the wrong and to back off. So when we suspected the mold problem we did not want to deal with the landlord until we knew for sure because we did not think he would even answer our call. We hired a company to test and we were right. There was excessive mold found in the house. Can we deduct from our rent for the testing we did even though we did not tell the landlord about it first?