Pure Sine or Modified Sine Inverter?

[bboshart]

I'm deciding on a power backup system for my reef setup. I basically want to power my Mag12 main pump and the Coralreef 125 skimmer (for oxygenation) and possibly heater. I'm looking at the Xantrex XM1000 . It has GFCI, automatic transfer switch and made for humid conditions, but its modified sine wave not pure sine. I tested the Mag12 and skimmer pump with a cheap inverter and both seemed to run fine. With a deep cycle battery, I figure I could run the skimmer, main pump and heater for 4-6hrs. I know some UPS such as APC Smart-UPS have pure sine but not long run times. Is modified sine generally fine for aquarium pumps? Any other experience with the Mag12 and inverters?

[sherm71tank]

From my experience some aquarium pumps can run OK on modified sine wave but it's not good on them. I went with one of the a APC Smart UPS and added another battery to it. You can buy models that you can chain batteries simply by plugging them in or if you know your way around electronics a little just wire one in yourself. I would go with the Smart UPS to be safe.

[sherm71tank]

Here is mine that I just added a battery to. It's a Smart 1500.

[8BALL_99]

I use a inverter with a Modified wave on my ups.. Works fine for me.. I've been using it for a couple of years... Mine just runs my 3 return pumps. Most cheap computer UPS's won't have a charger that can handle external batteries. The ones that can Cost big bucks.