What is TDS creep?

You might have heard about the term "TDS creep" but never really understood what it is. Let's deep-dive into the term!

Background

TDS stands for Total Dissolved Solids. The lower the TDS, the better. Many mistakenly feel that if permeate TDS is rising, they need to replace the prefilters (sediment and carbon filters), but this is simply not true. They need to be replaced on a regular schedule - which is every 4-6 months. When the prefilters clog up with particulates, the pressure drops off and the membrane is less efficient, and when the carbon filters are spent, chlorine can begin to eat away at the membrane. 

So what is TDS creep?

When water sits in the membrane housing for a duration, TDS rises as it wicks out of the membrane. The initial 30 to 60 seconds when the purifier turns on will send this burst of TDS into your tank or faucet. Each time the RO system turns on, this occurs. This happens to all RO systems, no matter the brand.

How do we avoid TDS creep?

Luckily, your Bluewater machines will help you avoid TDS creep in the best possible ways! We will now take you through the different alternatives:

1. Automatic flush sequence.
   
   
   
   In order to avoid TDS creep being built up, all Bluewater purifiers perform an automatic clean flush every 6 hours. The machine then takes a small amount of inlet water to rinse out the membrane and replace the water inside the membrane vessel. By doing so, you will never have a large build-up of TDS creep. 
2. TDS indicators on the machine.
   
   
   
   All Bluewater machines are fitted with TDS indicators on the front. At the beginning of each production cycle, either triggered by you opening a faucet or if the pressure drops in a connected tank, the machines will indicate how pure the water is. By following these indications you will be able to tell when the machine has removed the TDS creep in the membrane. 
   
   1. On the Cleone, the front LED will blink when being below 85% purification. Once it reaches above this threshold, it will stop blinking. 
   2. The Spirit blinks on the "Service" LED when it is below 85% purification. Once it stops blinking, it has reached above this threshold.
   3. The pro has three LED's indicating different purification levels. Purification I is lit when the purifier is below 50%, purification II is lit when below 85% and Purification
      III is lit when above 85%
3. Pro rinse valve.

If you have applications where the water needs to be extremely pure directly when it is delivered, such as a laboratory, then we have the option for you. Our Pro CV-series are equipped with a pure water rinse valve that measures both the inlet and outlet water quality and discards of all water that is below Purification level III. By doing so, you are completely sure that all water coming out of the machine is of excellent standard. This is extra important when working with storage tanks after a machine as holding vessels can attract any impurities that comes with the water.