What is the amp draw of the pump? I have one that can run a 55 gallon and it only draws 25-35 watts. Maybe you you have problem with a circuit. Have you checked wiring or draw on you pump, fan, etc? Tools of the trade are pricesless. I use the meter with the claw so I know the draw, and a regular meter to check for bad common etc. Home d sells a circuit checker with three lights in it. It tells you if you have a wiring issue and what it is. It so easy to use I bought one when I built my grow house and it saved me a mountain of money I would have had to pay an electrician for wiring the buildg, so I took the savings and used 12 gauge instead of 14. I can draw what I want all I have to do is plug into my heavy circuits and draw 30 amp. I go overboard on wiring safety. I have seen what being cheap got others, burnt to the ground. If you know your draw you know you are safe, never exceed 13amp on a 15 supply and no problems, you need a cushion for things that fire up higher than they run, and know the fire up rate and adjust draw on that circuit. If it fires in at 8 amps and runs at 5 guess what? you count the 8 then add your next appliance load. Yes tools are expensive, but they are priceless in the return of bud and safety and being able to reproduce without stress. I buy descent tools and then find good inexpensive off the shelf shit and love every minute. Terminal block and timer is like 300.00 my set up can run 10 amp pump and 3 amp air pump, now that is fucking extreme, but you get it. My pump for 55 gall res runs25 watts, my air pump is for a 100 gall res 35watt. Super low draw and 14 amps to spare. I have a friend that buys the cheapest meters I have ever seen I think he bought the circuit checker, amp probe and tester for less than a 100.00, cheap chinese tools, but his shit never fails. You can do this it is easy. Knowing is half the battle soldier, the other half is getting off of lazy and doing it lol. Peace DD