Help with water chem and recipe please.

I've been browsing these forums for the past month diving into every new topic I see. If I had this much enthusiasm about my major I would have long been done with college and know those texts inside out, but alas that isn't the case.

Anyway, on to my questions:
I have had that metal tang to my first few extract brews and I have been very careful with sanitation and ingredients. I have narrowed this down to the water quality and pH. I'm pretty sure my tap water is well over 200ppm and very high in iron if that matters. I have not been keeping track of my pH while doing these first extracts.

I'm attempting my first AG (Winter warmer) this week and want to do things right. I plan to use all RO water and need some help with salt additions. I have Palmer's RA chart and am trying to figure out additions.

I am brewing a brown that I want to be about 20 SRM
I have some gypsum and hopefully I can find other materials at the local shop. It doesn't have much.
I want my mash to be about 5.2 pH?
10 lbs of malts so at about 1.5 qt / lb = 3.75 gallons of mash water. I'm probably going with about 3.5 gallons.
Could I get away with 3 gallons of sparge water?

Here are the base ingredients I plan on using. Please feel free to throw in some comments about them.

Recipe: Carmel apple winter warmer (5 gallons)
8 lbs Maris Otter Pale
1 lb Muntons Dark Crystal Malt
1 lb Belgian Special B
1 oz hops 60m. I haven't decided what kind yet. I wanted american cascade but my local place was out.
1 oz kent goldings the last 10 min

I also plan to add a bit of cocoa powder and apples at the appropriate times. I haven't decided how much cocoa powder yet and I'm thinking about 4 lbs of apples.

Thanks for all your help in advance

If I was you I would just cut my RO water with some of your tap water. Drop a campden tablet in it and that will help with chloromine and a preboil helps with chlorine.

That is the lazy mans way to do it without messing with all of the salts.

Reverend JC said:

If I was you I would just cut my RO water with some of your tap water. Drop a campden tablet in it and that will help with chloromine and a preboil helps with chlorine.

That is the lazy mans way to do it without messing with all of the salts.

Click to expand...

If I go this way would I use different ratios for different types of beer?

Lighter beers maybe a ratio of 1 part tap water to 2 parts RO
and for darker beers just 1/2 of each?