Just bought a RODI unit

[laezur]

Just bought a RODI unit, was only 50GPD so I don’t expect a fast stream but just want to make sure this is normal. I have got the lightest of drips going into my Jerry can, and a stream going into waste.

I know it wasted about 70% this just seems insane, it’ll take years to fill that Jerry can haha. Water bill will be through the roof.

Video:

 

[LeftyReefer]

How much filtered water are you getting compared to waste water? can you give us an idea of the ratio between them?

Are you getting 1 cup of filtered water and 3 cups of waste water or are you getting 1 cup of filtered water to 10 cups of waste water? give us an idea of the product to waste water ratio that you are currently getting. Just run the unit for a a bit and capture the output of each line and then compare them to each other. Are you getting twice the waste water or ten times waste water?

Do you know the water pressure? if it's too low, it can cause low output from the RO membrane. Adding a booster pump might be all you need if that is the issue.

There are things that can be done to help fix this, but typically costs money. adding a booster pump or a second membrane, or maybe both.

 

[laezur]

How much filtered water are you getting compared to waste water? can you give us an idea of the ratio between them?

Are you getting 1 cup of filtered water and 3 cups of waste water or are you getting 1 cup of filtered water to 10 cups of waste water? give us an idea of the product to waste water ratio that you are currently getting. Just run the unit for a a bit and capture the output of each line and then compare them to each other. Are you getting twice the waste water or ten times waste water?

Do you know the water pressure? if it's too low, it can cause low output from the RO membrane. Adding a booster pump might be all you need if that is the issue.

There are things that can be done to help fix this, but typically costs money. adding a booster pump or a second membrane, or maybe both.

I can measure all of these things for you, but I’m going to go ahead and assume by your response that the outputs in the video are NOT normal in that case?

 

[PatW]

My unit is rated at 75 gpd. I think it produces at least that amount and possibly more.

50 gpd is on the low end. But if you have the sediment filter, carbon block(s), RO filter and DI canister and produce 0 tds RODI water.

I just set my system to fill up a 45 gallon Brute Trashcan. I have an automatic shut off - bulk reef supply sells them pretty inexpensively. I leave it running and it shuts off automatically once it is filled.

As long as you do not have a really large system, 50 GPD should be enough.

 

[laezur]

My unit is rated at 75 gpd. I think it produces at least that amount and possibly more.

50 gpd is on the low end. But if you have the sediment filter, carbon block(s), RO filter and DI canister and produce 0 tds RODI water.

I just set my system to fill up a 45 gallon Brute Trashcan. I have an automatic shut off - bulk reef supply sells them pretty inexpensively. I leave it running and it shuts off automatically once it is filled.

As long as you do not have a really large system, 50 GPD should be enough.

I have a 170 litre (34 gallon display) so it should fill the tank each day which is fine for me since I won’t be topping up a whole tank per day haha.

I’ve just checked my boiler pressure and it’s at 1 bar…. Infuriating. HOWEVER I’m using the outside tap, and I have no idea of the pressure out there, but I assume it is different to what the boiler pushes out since it’s not connected to the boiler.

 

[LeftyReefer]

I can measure all of these things for you, but I’m going to go ahead and assume by your response that the outputs in the video are NOT normal in that case?

I couldn't tell off the video, that's why I'm asking...

What does your unit say it should be producing product to waste wise?

My unit makes 1:2.5 so for every gallon of filtered product water, it produces about 2.5 gallons of waste. that is pretty typical of most units I think. If you add a booster pump or second membrane, you can get it down closer to 1:1 or 1:1.5

 

[laezur]

I couldn't tell off the video, that's why I'm asking...

What does your unit say it should be producing product to waste wise?

My unit makes 1:2.5 so for every gallon of filtered product water, it produces about 2.5 gallons of waste. that is pretty typical of most units I think. If you add a booster pump or second membrane, you can get it down closer to 1:1 or 1:1.5

The manual says it will waste around 70% of water but does not specifically ratio the pure to waste.
I’m guessing I might need a booster which is really annoying. Judging by how much it’s currently created it’s going to take a good 4 hours to fill a 25 litre Jerry at this rate

 

[LeftyReefer]

A 50GPD unit should make 50 gallons in 24 hours, or roughly a little over 2 gallons per hour.

 

[laezur]

A 50GPD unit should make 50 gallons in 24 hours, or roughly a little over 2 gallons per hour.

Well that kind of makes sense, I thought they were measuring a day in terms of daylight so about 8 hours (don’t ask me why I thought this, I’m dumb).

Seems okay then. just disheartening to see literal drops coming out, I could spit a 25 litre Jerry can full faster than this hahaha. Just cautious of water waste, I don’t have a water butt to re-use water so it’s all going down the drain and into my bills. Makes me wonder if this is cheaper than getting taxi’s to my LFS after all

 

[Shirak]

Is there a bypass valve on the waste line? There should be a flow restrictor which reduces waste and helps increase RODI output. Sometimes there is a bypass valve where the flow restrictor is so that you can 'flush' the membrane and send a lot of water out the waste line quickly.

 

[laezur]

Is there a bypass valve on the waste line? There should be a flow restrictor which reduces waste and helps increase RODI output

Interesting, there might be I’ll have to check the manual and contents I didn’t use. It came with a bunch of stuff to use should I connect it to my mains, but I chose to connect it to the outside tap instead

 

[Freenow54]

Just bought a RODI unit, was only 50GPD so I don’t expect a fast stream but just want to make sure this is normal. I have got the lightest of drips going into my Jerry can, and a stream going into waste.

I know it wasted about 70% this just seems insane, it’ll take years to fill that Jerry can haha. Water bill will be through the roof.

Video:

That is why I recommend a watts zero waste to everyone that asks

 

[Shirak]

Don't see a flush valve but I see what looks like a flow restrictor near the setup on the waste line. After watching the video your pressure is SUPER low.. which is why I think you are getting such low output on the RODI. Do you have the tap wide open?

 

[Woodyman]

Well that kind of makes sense, I thought they were measuring a day in terms of daylight so about 8 hours (don’t ask me why I thought this, I’m dumb).

Seems okay then. just disheartening to see literal drops coming out, I could spit a 25 litre Jerry can full faster than this hahaha. Just cautious of water waste, I don’t have a water butt to re-use water so it’s all going down the drain and into my bills. Makes me wonder if this is cheaper than getting taxi’s to my LFS after all

A booster pump and second membrane will help with your production speed and efficiency.

It's often overlooked as everyone assumes their pressure is ok, and in reality it is. However, those GPD ratings are at a given pressure and temp. So if the unit is rated for 50 GPD at 80psi and 70°F and you only provide 60psi and 55°F your not going to get the states production of 50 GPD.

Now on the other hand RO systems will function with low pressure. They just don't work as efficiently or quickly.

 

[laezur]

Don't see a flush valve but I see what looks like a flow restrictor near the setup on the waste line. After watching the video your pressure is SUPER low.. which is why I think you are getting such low output on the RODI. Do you have the tap wide open?

I believe the tap is as wide open as it gets yeah. Pressure is super low, you’re right. My boiler is reading ONE bar. Depressing lol.

 

[laezur]

So I put a timer on and after 45 minutes this is where we are up to on a 25 litre Jerry

 

[Woodyman]

So I put a timer on and after 45 minutes this is where we are up to on a 25 litre Jerry

Booster will be the route to go. Also when you replace the membrane I'd upgrade to a 90 or 100 GPD membrane/flow restriction. Even if you don't need that much a higher rated membrane will produce more water in the same time.

For example if all you did was change your 50 GPD to a 100 GPD membrane you would have ~double what you've got now in the container. A booster will increase that even more.

 

[laezur]

Booster will be the route to go. Also when you replace the membrane I'd upgrade to a 90 or 100 GPD membrane/flow restriction. Even if you don't need that much a higher rated membrane will produce more water in the same time.

For example if all you did was change your 50 GPD to a 100 GPD membrane you would have ~double what you've got now in the container. A booster will increase that even more.

I should have gone with the 100 initially, I was working on a budget and just went for what I thought was the cheapest and optimal for a 30-40 gallon. I should have just paid the extra haha

 

[Woodyman]

I should have gone with the 100 initially, I was working on a budget and just went for what I thought was the cheapest and optimal for a 30-40 gallon. I should have just paid the extra haha

Often we all do that at one point or another.

You know how to correct it, your unit is still a good starting point and ultimately you learned more about and the process. That's worth something.

I'd invest in the booster first before swapping the membrane.

 

[ying yang]

I’ve just checked my boiler pressure and it’s at 1 bar…. Infuriating. HOWEVER I’m using the outside tap, and I have no idea of the pressure out there, but I assume it is different to what the boiler pushes out since it’s not connected to the boiler.

I guess you got a combi boiler ?
So that pressure reading on pressure gauge is the pressure inside your central heating circuit ,which is a closed system ( as when gas engineers Install a system they put a cleanser in and then run system then flush system then add an inhibitor to protect system ) so hot water and central heating water never mix,as strong chemicals in the cleanser and inhibitor.
So if that 1 bar you reading on front your combi boiler,just disregard that as that is different than your mains pressure,when people in this thread asking what's your pressure, they mean your incoming cold mains pressure .
My 25 litre container takes avout 1.5-2 hours to fill from my 50gpd rodi unit with booster pump.
I'm a plumbing and heating engineer but my experience on rodi units not so much,fitted a few under sink units and owned one rodi unit myself which I just plumbed in under my sink ( you could do same very easily as cold mains there and waste there for your sink. And no need soldering skills as can use compression fittings or even pushfit fittings. Compressing fittings just need 2 adjustable spanners/ pump pliers and push fit do exactly that as push into fit them then tighten nut by hand .

But from what you saying and video I first thought have you got the flush valve open so getting drip out the product water and good stream out the waste water.

But I think I seen you make another thread mentioning you in a rented apartment? If so what floor you on ? As higher the water got to travel, it loses pressure,flow stays same but pressure drops ( unless its pumped up ) but something to bear in mind,you can get a pressure gauge cheap enough ( guessing you in Manchester England) from somewhere possibly like b and q or tool station to fit onto your rodi tubing and see the pressure you got on your cold main,then if it's lower that recommended then a booster pump be a good investment.

I've got a vyair rodi with booster pump and wasn't that expensive and been great for me.will see if can link it,not saying you should buy another as I'm guessing you juat bought this unit,but if ever buy another then look Into vyair