Partially Explained

As I laid in out in yesterdays posting I have (so far) taken samples from the barrel with no bleach, 5.8 ml of bleach and 58 ml of bleach; currently the barrel has been dosed up to the max of 580 ml of bleach and it is equilibrating. I tested the samples of the first three doses with the high sensitivity/low threshold dipsticks from dialysis. My prediction was that it would be pointless to even test the maximal dose as the threshold should be met or exceeded by the third sample (58 ml or ten times our predicted dose). The samples behaved as predicted.

The level that dose our calculation was predicted to produce was 2.5 mg/L; this batch again shows it somewhere in the range of 0.02 - 0.05 mg/L or 1/100th of expected. When the bleach dose was increased tenfold (58 ml in the barrel) the threshold of the test strips, 0.2 mg/L, was exceeded (as predicted). I bet that using different scaled strips it would fall somewhere in then range of 0.2-0.5 mg/L. The whole thing is off by 100 fold and I have a feeling it has something to do with the base assumption of the bleach strength expressed as a % (ie, 8.25%). Our calculations are based on the assumption that 8.25% means 8.25 grams of Sodium hypochlorite in 100 grams of water. This may be an incorrect assumption. However, in the absence of a better explanation the new empiric value rules and it would work out to something on the order of either ~ cups of 8.25% or ~3 cups of 5.25% bleach per 55 gallon drum.

I will finish up the last set of samples (580 ml - which should yield the target range of 2.5 mg/L) and cart them up to Frank for definitive testing. I also have a 4 gallon tank (blue) of untreated rainwater for him to use in anything he sees fit.

If anyone reading this finds it tedious, I apologize. Just thought you might want to know...