This is gonna be interesting. Given that your water supply has a high lead content, that is most likely the reason the water is brown.
In addition to the filter you made, you're gonna need to go to a pool supply place and get a sequestration product for metals. They usually go by names like "metal out " or "metal gone". The pool store will know what you are looking for. The directions on the bottle should tell you how much to add per 1000 gallons of water if you already have metals in your water. Multiply the amount it says to add per thousand gallons of water by 3.2 and that is the amount you should add to the pool. The metal out product should bind with the iron in the water and it should fall out, clearing the water. Follow the directions on the product for brushing/vacuuming the pool.
Once the water is clear you are probably gonna need do a weekly maintenance doseage because you are always gonna be adding water to the pool because of splash out from swimmers, evaporation from the sun or backwashing the filter. The product should also give the amounts for maintenance.
Stabilizing the Water:
You need to add stabilizer now to keep the sun from eating up all the chlorine. You can do this with 1 of 2 products, liquid stabilizer or dry(granular) stabilizer.
With liquid stabilizer you can get all of the stabilizer in the water at one time.
The only "con" to liquid stabilizer is it's more expensive.
If you decide on liquid stabilizer you will need to add 39 ounces to increase the CYA(stabilizer) level to 35ppm.
How to add:
With a clean filter and the pump running, Pour the specified amount of stabilizer VERY SLOWLY into the skimmer. After you have poured the stabilizer into the filter you must let the pump run continuously for 48 hours
Some articles/sites recommend a cya level of 50-60 ppm, but that is not needed to protect the chlorine in the pool. And the higher the cya level is, the higher the free chlorine level must be to sanitize the pool.
If you decide on dry stabilizer you will need 15oz to increase the cya level in your 3200 gal pool to 35ppm.
Some articles I've seen say that you can simply broadcast the stabilizer over the pool water. DONT Do THAT! There is a real possibility that you can damage the liner.
Some articles say to dissolve the stabilizer in a 5 gal bucket of water and then pour it in the pool. The only problem with that is that 5 gallons of water will never dissolve more than a few ounces of stabilizer and it takes about 48 hrs. So you would need 10-15 days to dissolve 15 ounces.
The best way to add dry stabilizer to the pool is to take the whole 15 ounces and put it in a pantry hose leg, Make a structure so you can hang the pantyhose in front of the return opening but not touching the wall. Then just let the filter run. Every 3-4 hours squeeze the stabilizer in the pantyhose to help it dissipate faster. Let the pump run until all of the stabilizer is gone and for an additional 48 hours.
The recommended chlorine level for a pool your size with a cya level of 35 ppm is 3 to 4 ppm
The type of sanitizer you use dictates how much you need. ie;
You need 17 oz of 8% strength liquid bleach
You would need 2.5 oz of 65% cal- hypo granular chlorine, etc,
And you should check the chlorine levels every day to make sure you maintain 3-4 ppm free chlorine. Most chlorine products will tell you how much you should add to increase the chlorine levels 1 ppm.
As a last thing, where did you get the readings for the chemical levels? Did you do them with a kit or did you take a water sample to a pool store?
I'm concerned about the very high total alkalinity levels.