@tima,
@Kingrex,
1. The average eyedropper can vary between 0.04 to 0.06-ml/drop. If we assume 0.05-ml/drop, then 8 drops = 0.4-ml/6000-ml = 0.0067%. This is just above the no-rinse wetting solution concentration but just below enough (0.0075%) to get some detergency. Since you are rinsing, I would recommend increasing the concentration to 0.0075%, and by using the Nalgene Dropper Bottle you would add 11-drops. If you accidently add 12-drops, no problem.
2. As I alluded to above, I now recommend for smaller tanks, to use the Nalgene Dropper Bottle because it is designed to deliver 0.04-ml/drop - it has been measured to be quite accurate -
Factors to consider in accuracy and precision of Nalgene Dropper Bottles (thermofisher.com), and very cheap -
Nalgene 2 oz. Leakproof Travel Dropper Bottle | The Container Store and will last a very long time.
3. Are you adequately rinsing the Tergitol in the Spin-Clean with Zero water - yes. But I would recommend you refresh the Spin-Clean every 10-15 records, and here is the math.
a. Assuming 0.0075% = 75 ppm, = 75-mg Tergitol/1000-ml = 0.075-mg/ml
b. Assume 5-ml drag out from the Kirmuss to the Spin-Clean. Therefore, every record rinsed adds (5-ml) x (0.075-mg/ml) = 0.375-mg of Tergitol to the Spin-Clean tank.
c. The Spin-Clean tank is ~650-ml. So (0.375-mg/record)/(0.650-L) = 0.6 mg/L = 0.6-ppm/record. So, every record that is rinsed, will raise the Tergitol concentration in the Spin-Clean (from drag-out) by 0.6-ppm.
d. Refresh the Spin-Clean at 10-ppm to ensure no deleterious residue, so (10-ppm)/(0.6-ppm/record) = 17-records.
e. However, to account for what was cleaned from the record, we add a 25% margin for uncertainty, so (17-records) x (0.75) = 13 records. But the detritus concentration (from the record) in the Kirnuss tank increases with every record cleaned, so we arbitrarily expand the range to refresh the Spin-Clean at 10-15 records.
Take care,
Neil