having trouble with the numbers

Did 7 fast miles on the mountain bike today and my head isn't handling my numbers well for palmer's spreadsheet.

I'm trying to brew a RIS with SRM about 55

mash water volume is 4.5 gallons

here are my source numbers (i know, almost distilled)
Calcium 8
Magnesium 2
Alkalinity as CaCO3 20
Sodium 7
Chloride 5
Sulfate 2
Water pH 7.7

Whenever i enter the numbers into palmers spreadsheet, some of them turn red, which i assume indicates that they are too high to use.

Could someone help me craft a balanced water for this beer, please? All suggestions are welcome, but anything that involves changing the recipe is out as i've already received my grains and they are mixed together.

here was my first attempt

Chalk CaCO3 7
Gypsum CaSO4 *2H2O 3
Calcium Chloride CaCl2*2H2O 7
Epsom Salt MgSO4 *7H2O 3
Baking Soda NaHCO3 18

Here are my suggestions:

Treat the Mash with:

3 grams of Epsom Salts and 2 grams of Salt. Get non-Iodinized salt if you can. I found, 'Sea Salt' in the spice section of the super market which is pure NaCl... some other salts w/out Iodine contain (and I know I can't spell this) yellow prussate of soda in them. I don't know the effect of this on my brew but I'm not taking a chance

Here is the cool thing with your soft water. You can add no NaHCO3 (baking soda) and have a balanced Cl:SO4 ratio and brew a beer in the range of 5 to 10 SRM, a luxury many of us with hard water have a harder time getting to. If you add 1 gram of baking soda to the above recipe the Cl:SO4 ratio remains the same but now the SRM range of your brew is between 8 and 13. Add another gram of NaHCO3 and your SRM range is between 11 and 16, all the while the Cl:SO4 ratio remains constant. 4 g's of Baking Soda and your almost brewing Guiness

So your recipe:
Starting Numbers-

Calcium 8
Magnesium 2
Alkalinity as CaCO3 20
Sodium 7
Chloride 5
Sulfate 2
Water pH 7.7

Additions:
3 grams Epsom Salts
2 grams of non-iodinized salt
This changes your water to:

Ca Mg Na Cl SO4 TA
8, 18, 53, 76,71, 20

I'd probably add another gram of Baking soda to bring up the TA a bit.

Ca Mg Na Cl SO4 TA
8, 18, 69, 76, 71, 55

The geeky, but important, stuff here is the RA and the Chloride to Sulphate ratio. Almost 1:1 here gives you the 'balanced water' that you asked for.

You can tweek that ratio one way or the other and change the water to suit your style of brew. Add another 1 gram or 2 of gypsum, CaSO4 and your ratio goes to the bitter side, take away 1 gram of Epsom salts and your a Malty guy (or gal).

So, baking soda brings the color of the beer up from light to dark for you and gypsum brings the Cl:SO4 ratio towards the 1:2+ range, removing Epsom salts gives you a malty profile.

These are all riffs off your basic balanced profile we did above.

Btw, these are salt treatments ONLY for your mash water (4.5Gal), don't treat the sparge water with salts.

I use the: http://www.ezwatercalculator.com/ to do my calculations. It was written by an HBT member TH ... It is awesome and eazy to use