How is the power in your neighbourhood? Any recent power outages or wind storms?

I'm not sure how sensitive MH ballasts are to power fluctuations but I have seen dirty power issues cause all sorts of problems. It is a very difficult thing to track down as well. There is a device called a voltage recorder than is basically tracks the voltage over a 24 hour period to look for fluctuations/surges. Not something most people have laying around.

I am told surge protectors to very little to actually stop anything other than a very large surge. A UPS is supposed to be one of the better ways to filter your power.

Another thing to check would be your bulbs. There's the probe/pulse bulbs and each require different ballasts. Something that can be overlooked, and could be why the ballast's are failing.

Here's Everything You Need to Know About Metal Halide Lamps and Ballasts

All three PFO ballasts were brand new, and the Galaxy's as well. That's six ballasts total.
I tested the voltages after the failure of the first three, everything seemed to be fine, nothing looked out of range.

I haven't but I have two most recent failures I can crack open.

I'm running 400W DE HQI Bulbs and Ballasts

The power is pretty good, I can't recall the last time the power went out. No lights flickering randomly etc.

Are there any major appliances on the same breaker, (dishwasher, washing machine)?

It really sounds like either the ballasts are overheating or there are voltage level issues. A large draw will cause temporary voltage fluctuations. Hard to believe the ballasts wouldn't be able to handle it though.

Sorry I don't have better advice for you but I have seen "dirty power" destroy expensive electronics repeatadly while electricians and the hydro company both tested everything ok. The problem is most tests are only looking at the levels at that moment in time. I havn't heard if they where able to fix the problem once it was proven to exist.

I don't really know what I would do if I was in your position. The switch to LED may work, some sort of power filter or ups might help. You could call some local electricians to see if they have any advice or a voltage recorder to test over a longer period of time.

Good Luck!

I have a hard time believing you'd be overheating the ballasts to the point of failure just because they are in a stand. If they have plently of room all around it shouldnt be that much of an issue, if they needed a fan they would be built with one (as some are). On the other hand obviously the cooler the better and adding a fan would be a good idea regardless. Sounds to me the issue lies elsewhere. You may be overheating the ballast but I dont believe the reason is from sitting in a stand.

Nope, nothing. I have two dedicated 20 amp circuits for the tank.

Since I lost the first three the tank stand has been open, all the doors removed with the sump off-line, the only other thing generating heat under there would be my return pumps on the other side of the stand. The ballasts weren't running that hot if being able to hold them is any indication.

I'm not really sure what I'm going to do at this point, I'm really debating shutting it down for awhile, not selling anything other than livestock. I might just need a break, I've be fighting this tank for two years now, if it's not one thing it's another.

sounds like bad ballasts to me! 20 amps is more than enough (most breakers are only 15 amps) but heres a thought, have you tried firing your ballasts a few minutes apart from eachother to prevent a large surge? also I seen blue world has aquamedic reflux cube ballasts on sale right now for 110.00 Ive had one for 3 years and still going strong bar none the best setup Ive seen yet! built in cooling fan and no restriction to airflow across the windings. check them out you wont be dissapointed. stay away from the A.M. fixtures though had a spacelight pendant and junk is all i can say.:mrgreen: