tank is crashing!!!

[Ruth]

Test calcium, alk, and mg for sure. If you have cyano you probably won't get any readings for PO4 and nitrates are probably reading low as well. Do you have a way of testing to see if any stray voltage could be getting in your tank. I would also suggest checking your heater (make sure it's not stuck on or off) and your pumps to see if they might have cracked or somehow broken their seal.