RO System Recommendation

I know this has been asked countless times and will continue to be so apologies. I did try to send this as a PM to@spruce & @doug atkinson but it didn't let me.

"Hi, after reading a several post regarding RO systems it looks like you're the person to ask for advice.

I'm just starting out my window cleaning business ( I don't have any customers yet) so I'm not sure how much water I'll be using yet. I have a TDS of 300 from the garden tap, a flow rate of 20L per minute and a psi of 43. I will be working from a car with a backpack and a few water tanks. I have space for a 1000L IBC. Based on this info, what RO system would you recommend?

Thanks for reading,

Lemming."

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Hi @Lemming.

This is always such a difficult question to answer. To begin with I'm surprised that water at 43psi is giving 20lpm at your outside tap.

You are right inthat you need to use an r/o to process water.

The way I see it is that you have 3 choices.

You could invest in an r/o that produces water quickly such as a 4021 or a 4040 with a di vessel. You could also invest in a slower producing r/o with the same di vessel which would be a little less expensive. The third option would be to try to find someone to sell you water in the short term.

At 43psi you are very close to the boarder of needing a booster pump for either r/o.

Its always been my advise to go with the best you can afford and try to take long term goals into consideration. Of course one of the negatives is that you don't have any customers so buying equipment is always more of a risk than if you were already established. I don't mean to put you off window cleaning, so please understand that.

If you have the confidence and the drive to make this happen then there is no reason why you can't make it happen.

Lets consider the r/o. The smallest r/o I would advise for a single operator is a 450gpd unit. We started off with a 275gpd r/o but upgraded the membranes to 150gpd x 3 because we didn't have enough water. The 450gpd took between 28 and 36 hours to fill a 1000 liter IBC tank at 40psi water pressure and no booster pump. It just managed to supply 2 cleaners with some planning. (28 hours was when the water was warmer in summer and 36 was when the water was colder in winter.)

After 6 years of both of us drawing water from the same tank I upgraded to a 4040. Our water pressure is now 50psi and with an HF5 membrane the r/o produces 2lpm of pure. It takes around 8 hours to refill a 1000 liter IBC tank. As we never take more than 600 liters these days, the IBC tank is usually full by the time we get home. (The system is on a float switch which triggers a solenoid valve off when the IBC tank is full.

To begin with you won't use much water so I would probably go the route of a 450gpd r/o to start off with.

There are cheaper units out there than what @doug atkinson sells. But you pay for what you get. Doug will supply a top rate r/o system with membranes that are geared towards window cleaners as they are the most efficient. Cheaper r/o's will use cheaper Chinese sourced membranes that aren't as efficient. In the end running your system will cost more than you save with with your initial purchase price saving due to the extra resin costs to polish those remaining tds particles off.

I'm happy with a 6liter di vessel but you might consider something slightly bigger with higher tap water tds.

The other option is to look for a pure water seller and buy water from him until you get some sort of round established.

If you can invest in a van that’s one of the things I would recommend. Working from a car you will wreck it and your misses will not be pleased going on past experience.

An R/O system to suit your own needs a 450 gpd will suffice when filling an IBC. But as you grow you then want a bigger and faster R/O and most go for the 4040 system.

Thanks a lot for your replies. I can't afford to get a van just yet so I'm going to have to take as many precautions as I can with my car.

If I were to go for the 450gpd RO, what DI vessel would you recommend, the 11L? Would a couple of them be better than one or overkill?

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  I have never been a customer of Doug of Daqua but in recent times he has given me excellent advise and when I’m ready to upgrade my RO Doug is going to get my custom without a shadow of a doubt.

Lemming said:

Thanks a lot for your replies. I can't afford to get a van just yet so I'm going to have to take as many precautions as I can with my car.

If I were to go for the 450gpd RO, what DI vessel would you recommend, the 11L? Would a couple of them be better than one or overkill?

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Click to expand...

11 litre DI Vessel with1/4 inch push fits if you go for the 450 gpd

doug atkinson said:

11 litre DI Vessel with1/4 inch push fits if you go for the 450 gpd

Click to expand...

For the long term; a small r/o produces water very slowly, painfully slowly.

Fitting a bigger di vessel will take a long time to fill up before it starts to fill the IBC tank. You will be hovering around your tank and may even start to panic that this was the wrong purchase. But these r/o's are like a watched kettle that never boils.

It will also take near enough a weekend to fill the IBC tank but once you have built up a reserve (a full IBC tank) you will be fine.

Most use a submersible pump to transfer water to the van tank. You should be able to gravity fill 25 liter containers to begin with, but eventually as you grow you will need a pump to help with this.

I also found it worth while fitting an overflow connector onto the side of the tank connected to a length of 1/2" garden hose directed out of the garage to the drain. It saves flooding the garage or shed out should the IBC tank overflow for any reason.

Thank you for all your help guys. I ended up going for the 4021 from Daqua. I'm just setting it up now in a keter box which will be left in the garden. Before I start drilling holes into the side of it, can anybody please confirm that the layout of everything is fine in the picture? Cheers

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I should add that my only real concern is that in the instructions from Daqua it states that the filter housing should be mounted below the RO. I was unsure whether this was just a suggestion or a fundamental part of installation.

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Lemming said:

Thank you for all your help guys. I ended up going for the 4021 from Daqua. I'm just setting it up now in a keter box which will be left in the garden. Before I start drilling holes into the side of it, can anybody please confirm that the layout of everything is fine in the picture? Cheers

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View attachment 15127

Click to expand...

That looks okay but personally I would mount the R/O housing on the side.

doug atkinson said:

That looks okay but personally I would mount the R/O housing on the side.

Click to expand...

Can you tell me why please Doug?

well ive got the same item from daqua but where you've got the red waste valve/tap is where the outlet to the di/pure water goes. the waste tap should go out underneath. Are you sure thats correct? have they changed them doug?

You would be better to secure the unit to wood in the plastic box rather than try and secure direct to the plastic as the plastic car split easy

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marc674 said:

You would be better to secure the unit to wood in the plastic box rather than try and secure direct to the plastic as the plastic car split easy

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Click to expand...

Yes that's what I have done also insulated mine with 2" foam inside and out. 

@ks789 my outlets are as you described, you just can't see the other outlet because it's underneath the waste valve on the picture.

@mark674 that's a good idea. I'd also like to get something to better seal the holes I've created, something that will still let the house come through. I wouldn't know what to look for though.

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I would also like to see a frostat fitted in the box with a 140ww tube heater to protect the unit against the cold.

spruce said:

I would also like to see a frostat fitted in the box with a 140ww tube heater to protect the unit against the cold.

Click to expand...

I have insulated the box with a roll of insulation, however I don't think it will be enough. I would like to have a heater in there, any idea on how I'd get power to it?


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Lemming said:

I have insulated the box with a roll of insulation, however I don't think it will be enough. I would like to have a heater in there, any idea on how I'd get power to it?


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Click to expand...

Extension cable from the house.

spruce said:

Extension cable from the house.

Click to expand...

I was pondering that as an obvious solution but I've read it's dangerous as a permanent method.


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Lemming said:

I was pondering that as an obvious solution but I've read it's dangerous as a permanent method.


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Click to expand...

Then you could use Armour cable, 2.5mm 3 core and route it so its out of the way and won't be damaged. Armour cable is the correct stuff to use if you are running a permanent cable outside. You will have to get an electrician to connect it up with a proper junction box both sides.

Example

https://www.screwfix.com/p/prysmian-lv-armoured-6943x-3-core-cable-2-5mm-x-25m-black/38769

After flushing for 2 hours I'm getting a TDS of 30 out of the RO, with the input being 300, therefore a 90% rejection rate. My understanding is I can improve this by increasing my psi with a pump. I believe temperature effects the efficiency too, so would operating a heater inside the box result in an improved rate?

I guess I need to know would the cost of a pump for a better rejection rate save me money long term over the cost of resin, as the resin would last longer?

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