This subject is temporary ended so far. But @intra still need to search these points.
1. What is the min TL4 addition to chelate the 1000ppm Fe, now 30ml/L is still ok, how about lesser? Please find it! Based on NaOH 70g/L. I assume when NaOH up the addition of TL4 shall up too, in order to keep the chelating power. Please find out the ratio.
2. In next testing, please add Cu+2 50ppm together with Fe 1000ppm to evaluate the overall conditions.
3. Next step, adding Zn+2 500ppm ( plus Cu and Fe ) to evaluate.
4. Next step, add Cr+6 10 ppm ......
@intra firstly you must design an overall concept how to make this series testing in order ( convenient, no interrupting, precise and use less sources ).
This test will take some time, please find the free schedule to follow up. The target finished date is before 27/7.
Kind reminding:
1. All the brass panels been tested, after making the records, please for recycling use ( could be for Ni plating or others ), as you know the brass panel is not cheap.
2. Be aware of the carbon anode, it could be corroded after long use, check its condition, try to minimize the testing errors. I suggest you just use " mild steel " anode which is the actual one in the plating shops.