Wow ok, really surprised your pump is heating up that much water.
Mine only holds 5 gallons but i don't have the high temps, it must be hot where you are or your pump simply gets hot.
Maybe cut down on the additives, skip the
hydroguard and have your Ph around 6.8.
You must be experiencing evaporation so keep a large jug of cold water in the fridge and spike it with that.
I swear if you had a good pump it wouldn't and shouldn't be heating up that much water.
Personally i think it's the manifold, it's really small for such a large site tote, would you consider making a custom DIY manifold?