Basically with what you're giving us I can tell you three things.
1.)That is too hot if were talking ground temp. That is a late veg/flowering temp for your canopy. You are likely cooking your roots.
2.) You definitely need to ph. It doesn't matter what you use, unless you are using a pre-amended soil. They're expensive, and take a bit of work if you DIY. That's the tradeoff. You don't want to test ph and measure nutes, do it right ahead of time. Otherwise you will have no choice but to troubleshoot. Which includes PH-ing, whether you like it or not.
3.)I can't see where any of us told you Cal-Mag? Why ask for advice if you are just going to try what you think might work? You have to work on your communication. Your plants could very well end up dying because of this. It's definitely not looking good and you already lost yield.