This calculator needs to compute chemical adjustments that are performed by our pool operators. What we want is to have a calculator on our site that they can simply input their water testing readings into and it will compute the chemical adjustment for them. With chemical adjustments, there are five possible readings that we'll be able to adjust. Basically, the operator inputs where his water is now and compute it to where he wants it to be and how much of which chemical is needed to get it there. This is a seven step process. First is determining what reading they have and what they want it to be. This means their adjustment will either be determined from their Chlorine reading, ph Reading, Alkalinity Reading, Calcium Hardness Reading or Cyanuric Acid Reading. For each of these, we will use a constant variable of their ideal readings: CL = 5.0, ph = 7.5, Alkalinity = 100, Calcium Hardness = 300, Cyanuric Acid = 50. So, the operator would have their reading that they take at the pool (ie, 40 for alkalinity) and the calculator would know based on what reading they are doing what the STEP 1/Adjustment would be (100 - 40 = 60). Step is a constant number assigned to a chemical of what they need to use to make the adjustment. Step 3 is a number determined from the chemical of how many parts per million are required (This number will either be .2, 1 or 10.) Step 4 is their pool volume which they need to know. Then, they need to divide Step1/step 3 = step 5, divide Step 4/10,000 = step 6. Then multiple step 2 x 5 x 7, to get the amount of chemical they need to add. There will be additional pages I will post that have the process already developed on a sheet as well as the chemicals and their amounts.