Making an IPA with custom built water, can RA be this low??

[TrojanAnteater]

Hi folks, I recently started to try to learn about brewing water chemistry and for this IPA I'm building up from DI water. Have made kick ass IPA's using just Arrowhead mountain Spring, but trying to really accentuate that bitterness (fair amount of sulfate) here and hit a better mash pH. After additions of CaSO4 and MgSO4 (and acid malt), here is our profile (used EZwaterCalc)
Water Profile:
Ca: 76
Mg: 18
Na: 0
Cl: 0
SO4: 263
RA: -216
Estimated Mash pH: 5.42

There is also 4oz of Acid malt which pushes that RA way negative. Without the Acid malt the pH is upward of 5.56-5.58, which is still below 5.6, but it's getting close to the upper limit. I've come across a lot of water discussion/profiles but I've never seen anyone's RA THAT negative, although I have seen people say it's ok to have negative RA. Or should I maybe work on bringing the Sulfate down more close to 100 and live with a little higher mash pH?

Any suggestions/comments for me? Any input is really appreciated. In addition to the water profile, here is my malt profile...

10.75lbs 2-Row
2 lb Maris Otter
1 lb Carapils
1 lb Melanoidin Malt
8oz crystal 40
4oz Acid Malt

[mabrungard]

Since you are starting with very low alkalinity water (DI), and will be pushing the RA negative with a high calcium salt addition, there is no need for the acid malt addition for that brew. When I plug in a typical IPA grist of 90% pale and 10% crystal 40, the mash pH is going to get down around 5.2 to 5.3. If I add 4 oz acid malt, the pH falls well below that. 5.3 is a good lower end target and its suitable for an IPA. I wouldn't go lower.

Good luck with the brew. Let us know how it turns out pH wise. I strongly recommend against adding the acid malt in this case.

[TrojanAnteater]

Thanks Mab, we did omit the acid malt. Don't have a pH meter so no idea where that actually fell, but things turned out fine anyway.