# Twinstar - DIY



## rebel (1 Aug 2018)

I am keen to find a project to get started. I thought I might DIY a twinstar just for kicks and giggles. I might run it at night for aereation or something. 

Has anyone on the forum DIYed a unit? If so, any tips on longevity or technique?

TIA!


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## ian_m (1 Aug 2018)

Search the forum (I didn't find it) and internet and people have attempted their own Twinstar type thing...

However
- You need special (platinum, titanium, palladium ?) coated electrodes or else they corrode away into the water. Stainless steel is not good enough.
- The signal applied needs to be AC'ish (ie occasionally reverses polarity) to stop electrode corrosions and deposits.

We wait for you design....


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## rebel (1 Aug 2018)

That's interesting info @ian_m , thanks! I didn't realise it was going to be tricky!!!!

I've seen the Youtube stuff but they don't mention longevity ( I had some concerns  ) etc.


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## X3NiTH (1 Aug 2018)

I built an electrocoagulation device out of two pieces of SS mesh you get with some mosses, made a sandwich out of it with some PVC gutter guard as the filling. Took some coated wire (non copper cable salvaged from the guts of an old PC) and threaded it through the corners of each electrode twisted them in place then used hot glue to secure them in place and to ensure the connection is isolated from water (the connecting wire will corrode quickly otherwise). Assembled the sandwich using a couple of cable ties to keep it all together. Power source is an old power brick for an Xbox360 HD/DVD drive (yeah that format won out didn't it, lol), 12v DC 2.5A.

I have it running on a timer that has 10 programmable time slots. Having read a lot of technical papers on the subject I settled on a 60 minute run time which was divided over the 10 program slots running 6 minutes at a time. I programmed the first ON period one hour before lights off, this way I can visually confirm the unit is operational, second period is immediately after lights off and then the remaining time is divided up hourly or bi-hourly all the way until CO₂ comes on. 

Within about 15 minutes off the lights coming on the plants start to pearl telling me that my water is maximally saturated with O₂ and the water is crystal clear. I don't have real time 24hrs TDS monitoring on the tank so I can't tell how effective the coagulation effect is but I have measured what happens to iron in my tank, when I dose it at 0.1ppm Ferrous gluconate and 0.05ppm FeDTPA next day it reads less than 0.025ppm (guesstimative index being used here as its a JBL iron test kit, comparative analysis of the results to the printed card is subjective but I do know what iron I'm adding in ppm beforehand and its colour response change post treatment is barely detectable).

Stainless Steel is absolutely fine for this purpose being DIY, electrocoagulation devices for the treatment of wastewater in commercial settings run with either SS or Aluminium electrodes, Passivation is a thing so cleaning the electrodes is expected from time to time, dissolution will be a thing too which is why I opted to use SS as Fe is a nutrient. I've been running mine for a few months now and it took about two months of use to nearly fully passivate the electrode so I just dismantled it and went at the mesh with a stiff toothbrush and a citric acid solution (VICANT Tempo) with a pH of 2ish, all the metal carbonates attached to the electrode just came away into solution and I was left with shiny SS again, didn't notice any pitting on the SS surface so dissolution isn't a major thing in my water (GH8 KH9).


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## X3NiTH (1 Aug 2018)

Spelling mistake in the citric acid source, it's actually 'VICAT' Tempo, it's a setting retarder for their Prompt Cement.


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## rebel (2 Aug 2018)

@X3NiTH , Thanks for your reply! That sounds much more promising. What distance do you have the electrodes?

I have some SS mesh and will think of a nice design to house it. I am considering a PVC but need a thin enough section of it.


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## X3NiTH (2 Aug 2018)

It's about 2.5-3mm. I left the sides uncovered as the wire ends around the edges appear to be good nucleation sites.

My device is as basic as it comes straight DC no polarity switching (when I cleaned it I switched the polarity at the connection to the power pack so both meshes receive the same wear over time), from what I have read Pulse Electrocoagulation is the most effective method where the voltage is applied pulsed in the KHz range but it also has the polarity reversed on each pulse, which as Ian describes above kind of ACish, so a circuit needs to be designed to achieve this for DC, something flip flop something something (not found a good circuit design yet, a dedicated pulsed power supply for electrolysis would be good to have but they are pretty expensive).

There's a lot more going on with the polarity reversal and the high switching speed than just electrode passivation/dissolution mitigation, from what I have read in a paper (can't remember which one) it appears that the effect of Hydrogen and Oxygen being formed next to each other on the same electrode (polarity reversal) only separated by a very short time (pulse interval) that at the nano scale the gasses are cramming themselves into the interstitial spaces between water molecules and if in close proximity to each other they can solve back into water, which if I remember rightly was what Twinstar at one point said their device made as a byproduct, which prompted scepticism, well apparently the effect is real.

With the above in mind and my DIY effort not being pulsed polarity reversed I kept the electrode distance small so as to increase the chance of this happening spontaneously.

Regarding electrode substrate type, Twinstar is very likely to be using Platinized Titanium mesh for the electrodes, the reasoning for Platinum is that it is much more resistant to passivation and dissolution than other metals so the electrode longevity is more prolonged, problem is it's expensive so the cheaper solution is to coat another cheaper metal with it preferably one that has low reactivity like Titanium. The problem with these types of electrodes is that if dissolution occurs and the platinum coating is breached and the titanium then exposed  it will form an oxide layer beneath the platinum causing it flake off (this has been seen on the Twinstar electrodes when they have gone kaput).


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## ian_m (2 Aug 2018)

You could use something like this (timer relay, set switch to cnf) to reverse the polarity every hour.
https://uk.rs-online.com/web/p/time-delay-relays/8966813/

Might find cheaper China equivalent on Ebay.


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## rebel (2 Aug 2018)

Maybe like this one?

https://www.ebay.com.au/itm/Multi-f...imer+Relay&_from=R40&rt=nc&_trksid=m570.l1313


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## Barbara Turner (2 Aug 2018)

Be fun to do a inline electrode, I guess you might have issues with the hydrogen dissolving into the water. 
I would quite like to get my chihiros doctor out the tank. 

Ps has anyone put one on an oscilloscope to see what the output looks like?


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## ian_m (2 Aug 2018)

rebel said:


> Maybe like this one?
> 
> https://www.ebay.com.au/itm/Multi-function-MOS-Control-Relay-Cycle-Timer-Module-Delay-Time-Switch-DC-12-I8W2/253288522892?epid=2019447983&hash=item3af92c248c:g:0L4AAOSwPAxaITVf&_sacat=0&_nkw=Multi+Function+10+Timer+Relay&_from=R40&rt=nc&_trksid=m570.l1313


Not quite.

It needs a relay (or solid state) like this to alternately switch the polarity. Relay needs to be double pole double throw (DPDT).






Or you could copy my alternate switching relay circuit, from my dosing pumps, to alternately switch reverse the polarity each time you power on your circuit.
https://www.ukaps.org/forum/threads/diy-dual-peristaltic-dosing-pump-with-alternate-switching.22332/


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## Zeus. (2 Aug 2018)

Barbara Turner said:


> Be fun to do a inline electrode, I guess you might have issues with the hydrogen dissolving into the water.
> I would quite like to get my chihiros doctor out the tank.



Me too but would make the weekly descaling a pain. My water is technically too hard so get plenty of scale on it esp on highest setting.


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## rebel (4 Aug 2018)

Hey boys, how about this one??

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com.au/ulk/itm/172475437602


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## X3NiTH (4 Aug 2018)

Ideally you want polarity reversal on every pulse, and every pulse having a short interval (see below).

I had a dig around and found the paper (pdf) discussing Pulsed electrolysis and Nanobubble generation, which I suppose could be used as independent evidence to support Twinstars claim of only producing oxygen and water.

Transient nano bubbles and short time electrolysis.

Electrode wear is discussed in this paper and the effect is not unlike damage due to cavitation. The effect of wear was pronounced at 20kHz reversed polarity pulses, where bubble generation stopped. We want gas production but we also want the hydrogen to react with the oxygen and go back into water, ideally for each reversal of polarity and back again we want one water molecule and one oxygen atom free to form a gas.

For optimisation of pulse electrocoagulation another paper mentions frequency an order or two of magnitude lower than the above 20kHz having an effect (though not really elaborated on, graphs would've been nice though) shot in the dark somewhere between the 500Hz and 2000Hz range. This is the reason for the need to hook a Twinstar up to an oscilloscope, we can then see exactly what's going on. Here's the paper anyway (another pdf).

Electrocoagulation in Wastewater Treatment

Enjoy!


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## rebel (5 Aug 2018)

Thanks @ian_m and @X3NiTH for all your detailed info.

Currently reading about DPDT relays.


Also will read those two papers although way outside my scope. Keen to learn however.


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## rebel (5 Aug 2018)

Also this timer could control the said DPDT relay??

The timer in the link below can perform an infinite loop.

P1-3 operating modes:Open X seconds,disconnect Yseconds, infinite
loop.Users can set the relay timeX,Y;time setting similar to P1-2.Short
press K1,enter function offine-tuning set,The default function is:set up
an electric circuit the relay first open, press the K1,there lay first
close.Press again to repeat the default functionality.​

https://www.ebay.com.au/itm/12V-Home-Automation-Delay-Timer-Control-Switch-Relay-Module-Digital-display-LED/311354656981?epid=502893241&hash=item487e2f08d5:g:CKsAAOSwv0tVSsXo&_sacat=0&_nkw=digital+timer+relay&_from=R40&rt=nc&_trksid=p2334524.m570.l1313.TR12.TRC2.A0.H0.Xdigital+timer+relay.TRS0&LH_TitleDesc=0


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## rebel (5 Aug 2018)

I wonder whether one could use this DPDT relay.

https://www.ebay.com.au/itm/1Pcs-Dc...57.m570.l1313.TR9.TRC2.A0.H0.XDPDT+relay.TRS0

Maybe use a 24V DC supply.


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