1.) I have got a CM 690 case..as I understand it I can mount one 240 rad on the bottom and one on top..Is that correct?
Not sure, measure your case and your rads to find out. You might need to mod.
2.) Should I use decoupling gaskets or an Air box shroud for the fans?
3.)Can I run two pumps as I have two RASA RS240 kits?
You can run as many pumps as you want, it just depends how you are setting all this up. Not sure I understand why you went with 2 Rasa kits, when you could have gone with a good custom loop for similar cost.
4.) Which is the best way to run the loop....pump to rad. to rad. to cpu block to res.?
As stated in the WC sticky- loop order does not matter as long as your pump isn't sucking air.
5.) Would running both pumps in serial cause a problem or could they be run parallel..I don't believe there would be any benefits in running dual pumps on a single loop?
I don't follow your reasoning for buying 2 kits with 2 pumps if you hadn't already decided on your overall plan. This question can really only be answered once you state your loop plans.
6.)Can you use regular car anti-freeze as a coolant? I want to use royal purple
You can, but why? If you want color, just use colored tubing. Why do you need to use antifreeze? Are you running mixed metals or in freezing temperatures?
7.)What are the highest static pressure fan in the 20-25dB range?
This might be somewhat debatable, so let me ask you- what have you found so far that interests you?
8.)Is there a group for liquid cooling addicts?
I'd say any watercooling forum, but it really depends your knowledge level, community involvement and product market understanding.
9.)Which are the best GPU water blocks for dual 6870's?
You'll quickly find in watercooling that there isn't a simple answer to 'what is best'...there isn't usually a clear-cut answer to this; much of it is personal aesthetic and budget value for YOUR specific build.
10.) Should I use 1/2" fittings on the GPU blocks as all my other fittings are 1/2"?
I'll let you answer this for yourself. If you can explain why you wouldn't use the same size fittings as the rest of your loop, why would you use different sizes on your GPU blocks?
Yeah, this is the only way you'll be sure. Do you have them sitting there? If not, you should be able to find some good build logs or even some schematics of the radiator dimensions...I think FrozenCPU has exact lxwxh dimensions.
2.) Are fan shrouds useful?
We had a discussion on this a week or 2 ago on the forum. You are usually better off just running either push or pull (depending on fan speed) as a shroud makes minimal difference many times.
3.)Didn't think it out before my purchase..My stupidity
It happens, I was just curious as to what the need was.
5.)Refer to #3..Trying to make the best of what I got.
Got it, and understood. This helps.
6.) Just curious
It isn't going to perform any better than regular distilled water, just FYI. If you use something like this, go with a 30% mixture or so.
7.)I use CM Excaliber Fans ATM
This might be one we can get input on from other users, but there are several that would meet this criteria. What are you setting as a budget per fan?
8.)That was a joke
I know, but I was trying to give you some factual representation of my experience in watercooling forums has been. It's better to read and stay quiet until you've picked up the knowledge and lingo to participate in threads. I know this sounds 'rude', but most guys assume that if you are posting in forums, you either are asking very deep-level questions or providing valuable input. If not, you'll get the response, 'go read the stickies and come back later, noob'.
9.) GPU blocks are crazy expensive so I will check into that shortly
Check into universal GPU blocks. I've used the same MCW60's for several years on 5 (about to be 6 after today) different video card models.
If you haven't bought anything yet, why don't you just start over on your plan? If you already have the Rasa kits, just run them in serial at some point in the loop. This is probably a better idea than just pushing water through a pump that isn't running.
Already purchased two RASA RS 240's, 2 1 liter bottles of ekoolant, I have one already installed it works fantastic...Then I thought hey why not add another..well that was stupid...But I am gonna RMA the second one thats on the way and get some other goodies instead....I may get a better cpu block or something...or maybe an extra rad...Thx for the insight Rubix..Any other suggestions would be appreciated as I value your opinion very highly
You can ditch the coolant- distilled water works better.
The Rasa CPU block is still considered pretty good, but this is someone only you can really decide. I'd say just run only one pump in the entire loop if it's only a CPU+GPU loop. You can still use both rads as this would be a good idea...keep the extra pump/CPU block as backups, or sell them.