From my 16 years of experience, there are only two reasons for yellowing well water, one is too much iron and the other is too much tiny sediment.
Your process is Manganese sand filtration - quartz filtration - ion exchange - RO reverse osmosis
The pre-treatment link is too weak.
In the first step, you start with storm gas treatment. One way is to use the stratospheric flow pool, that is, you build a rectangular pool, the well water pumped in, so that the water from the pool on one side of the parallel overflow out of the overflow width of the best in the 5-12 M. Of course, but also to determine the combination of the amount of water you pick. Another way, buy a cooling tower and put it on a high place, the well water goes into the cooling tower first and out the bottom of the cooling tower.
The height of the storm is 3-5M.
Step 2, you need to increase the diameter of your manganese sand & quartz filter. I don't know what diameter you chose. Generally speaking, I use the following method: the water inlet is DN50, manganese sand and quartz sand filter diameter to 1.2 M. If the water inlet is DN100, it will be divided into two pipelines, respectively, the diameter of the filter 1.2 M, and then combined together after processing.
The third step, you are in front of the manganese sand filter and quartz sand filter, to add a disc valve can be adjusted flow.
If the well water is yellowing, you can reduce the flow rate so that the water flows through the filter layer slower, and it can become clear immediately.
Fourth, whether it is manganese sand or quartz sand filters, the height of the filter layer should be 1.2-1.6M.
Well water treatment is now turning into a profit-making project, which is a bad trend.
My advice to you is that the important investment to spend on the front of the storm gas facilities, quartz filters, manganese sand filters, do not spend on the subsequent ion exchange and RO reverse osmosis, because as an engineer, the back of the high profits, so push the back of the equipment.
The price of the equipment for pre-processing is low, and the engineers have no profit, and they want to be as small as possible. So the solution can not be.
Your manganese sand is too low in manganese, you also have to buy from Guangxi Mashan, Xiangtan Manganese Mine, Jiangxi Le Ping and so on.
Ion exchanger is necessary? Your hardness is not high. What is the cartridge of the security filter? Generally plus activated carbon filtration is good.
The point is that I don't know what the purpose of your well water is. Your current process is copied from others, surely it will not work.
If you need more detailed help, send me your email or phone number through Baidu station message.