Only way I'd do it is to have a extra thick concrete pad under it, the same idea as under a rock chimney.

I second the concrete pad. If that's not doable, then put some double 2x12 beams under the joist with post down to concrete footings w/rebar grids, not cinderblocks. One beam on each side & one in the middle.

Al

Separate support for the tub is the only way to go. It's not a problem to design some new support beams but the existing members in the deck where you tie in to may not be adequate. Remember, the loads on any new beams are ultimately transferd to the existing structure.

I do it both ways, from what you have going on I go for the slab as well. J

I assume you mean cutting out an 8x8 section in the deck and pouring a concrete pad? How thick should it be and also is this something I can do myself? (mixing it in a wheelbarrow and laying a wood or other type of form) Or would it be better and not too bad price wise to have a truck and/or crew come out and do it. (not sure its possible to get a truck back there, my blazer yes but cement truck may be asking too much)

Because your deck has some problems already cutting out that section and placing a slab down below then framing up from that if ya want sounds like a good idea. From up a 6'' deep,screen, low slump footing mix creet pad,that should do it. If you get a truck out there a person can rent a Georgia buggy to move the creet they are kinda fun to run. John

I see that for an 8x8 pad it'll cost about $500 done professionally. I need about 1.25 cubic yrds and figure the cost of buying that is around $100 and if I need to pour footers that'll be closer to 2 cubic yrds and run around $150 (if only I knew what I was doing). With the cost and lack of any concrete experience I am leaning towards perhaps cementing some 4x4x8' posts to support the tub after cutting out an 8x8 section in the deck and leveling them by digging or filling the ground so that none of the tub weight will be on the existing deck. I have alot more confidence in my woodworking by far and had hoped to keep costs down around $150 if at all possible. Is this a safe/smart way to go if I don't want to do something so permanent as the cement slab?

Not really, no I dont think so. J

Ok then the concensus seems to be cement. The only part I'm not really sure on is the footers since I know I have ground freeze here in michigan I assume they need to be placed in the ground. Is the idea to have the footers at 6" with 2" buried to keep anything from moving and then fill a 4" pad? Or is the idea to make the footers 8" with 2" buried and have the pad at 6" thick. Also what is a good width for the footers? Is wire mesh ok to use vs the iron rebar?(Will have to check local codes but would rather not have to ground the metal all the way back to the box).