Tank Support Advice

[aerofish]

I am hoping that someone can provide advice to make me feel at ease with a new tank going in. Have been running a nano-reef for 2 years and stumbled upon the 220 gallon setup I had been looking for. Now where to put it in the house and get it supported. Of course I did all the standard research and even reinforced the floor. Now a couple days before the move I am second guessing myself. Hoping people with experience can shed some light. Here is my situation.

Will go on the main level of the house which is above a crawlspace with a concrete floor (made into a workshop). The joist are 2x10x12 supported on three sides by concrete block walls 2 exterior 1 supporting. The other side is supported by a 2x10x12 iBeam. The bad part is based on the layout of the house, windows etc the tank has to go with the joist not perpendicular so I knew I needed to support it. What I did is double up the 2x10x12 joist under the tank. The tank will sit with 6 feet over the concrete supporting wall, and 2 foot over the other concrete wall. With the doubled joist there will be a total of 7 joist below the tank. The center of the tank is supported with a 18000lbs jack to the joist below the tank. Another jack is set under the ibeam inline with the joist under the tank. So by my calculations each joist is only carrying 300-400 lbs where it normal supports 640 lbs (i.e. 40psf across a single joist).

I know it is best to set it across the joist, but my logic is across the joist would be 4 joist, I now have 7. It will be right at the edges of all the joist, and the long side will be across a concrete wall. To me it seems over supported but as it gets closer to arriving I am doubting myself. The stand is also constructed heavy duty so that will distribute the weight well also.

I really appreciate all the help, I am sure I will have more questions once I get this thing setup. Attached is a crude picture of where it is going.