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Tuesday, 30 October 2012

RO Machine - Part 2

The RO Machine project is now starting to gain some pace, as i really want this in place in advance for the big fill of my Woodson Reef Tank and to carry out continued tops up, and water changes for my aquariums in future.

Recently i have got my hands on a nice pile of equipment from Osmotics, once again a top notch service from them.

01-New RO Parts.04 

Several key things to move the project forwards…

  • A couple of float sensors for high and low water level monitoring in the storage tank.
  • A HM Digital PS-202 TDS Controller
  • A diaphragm pump that will be used to transfer water from storage to the aquariums, and all the associated bits that go with it.
  • A TDS meter for on the fly checks.

A closer look at the PS-202.

03-HM Digital PS-202 TDS Controller.49

05-HM Digital PS-202 TDS Controller.11

Supplied sensors with the PS-202, and power cables.

06-HM Digital PS-202 TDS Controller.31

I switched out the supplied plug for a UK item and fired it up. Looks all industrial!

23-HM Digital PS-202 TDS Controller.39

I decided to go with this unit so i can be assured of accurate TDS control. I had experimented with making my own TDS measuring circuits with the Arduino board.

Although i had some success, i wasn't confident it was entirely accurate. So made the decision to have a proper instrument to look after that side of things. I will use the switching outputs of the controller to signal to the Arduino with straight forward high and low signals as to when the TDS is at the appropriate levels.

Going back to Part 1, i purchase various pipe fittings in anticipation of making measurement cells for the PS-202 sensors.

Using a T-Piece…

07-HM Digital PS-202 TDS Controller.53

The sensor would be mounted in the Tee with the water passing through the continuous part.

However the sensors threads are substantially shorted than the Tee, so i have had to modify it slightly.

08-HM Digital PS-202 TDS Controller.44

I have simply cut down the Tee section to the same number of threads and then opened out the lower portion, in order to wind the sensor in as much as possible.

09-HM Digital PS-202 TDS Controller.24

It’s not the prettiest of jobs but hopeful it will work…

10-HM Digital PS-202 TDS Controller.34

As low as i could get the sensor into the Tee. The electrodes are expose into the flow, hopefully this will be enough. Failing that i will have to try something else.

11-HM Digital PS-202 TDS Controller.50

Reducing bushes added…

12-HM Digital PS-202 TDS Controller.12

And John Guest connectors for 1/4” tubing…

13-HM Digital PS-202 TDS Controller.57

Doesn’t look too bad i must admit! (Bar the scuff from the Dremel sanding bit!)

A quick wet test, wasn’t completely successful…

14-HM Digital PS-202 TDS Controller.40

The reducers and the John Guest fittings are absolutely fine. But under pressure, a tiny amount of water was making its way out of the threads of the sensor.

The fit was a little loose and i applied liberal amounts of PTFE tape and tightened them as much as dare, but still got a tiny spurt.

So i worked how to seal them, considering glue and silicone, in the end i reached for a piece of D-D Reef Putty. As this stuff goes pretty rock solid and can potentially stop leaks… even when wet.

I'm not entirely sure if this was a genius or stupid idea as of yet, but we will soon find out when its had time to cure!

15-HM Digital PS-203

More tomorrow on the second test!

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