What’s a good level to have on TDS with RO water?

[Emma01]

Hi everyone.
Just invested in RO unit and installed today.
I’ve a TDS meter, so now wondering what’s a ‘good’ level for RO water reading? Mine is coming up as 10ppm. Too high?
Thanks

 

[steelwrap]

Coming out you want zero

 

[dantimdad]

If you are only using RO then, yes, you want 0 but that is very hard with most water supplies.

If you are using RO and DI then after the DI should be 0.

I hope this helps.

 

[Flippers4pups]

I agree^. If your RO unit doesn't have a DI chamber, you need to add one.

 

[Emma01]

Hi again!
I’ve looked into getting DI unit for my current DDO RO unit. I’ve a couple questions though if anyone can help? .........
Does the
TMC V2Pure De-Ionisation Pod (500ml) inc Resin unit fit onto the DDO RO unit
And if so.......
How does it go on/fix in place ?
Thanks everyone x

 

[Scrubber_steve]

Hi everyone.
Just invested in RO unit and installed today.
I’ve a TDS meter, so now wondering what’s a ‘good’ level for RO water reading? Mine is coming up as 10ppm. Too high?
Thanks

Measure TDS of source water. You want a 90 to 95% reduction after the RO filter unit. Wait a few minutes before taking the reading (TDS creep).
If using a Deionising filter after the RO, then the TDS reading should be zero at the end point.

 

[Emma01]

Measure TDS of source water. You want a 90 to 95% reduction after the RO filter unit. Wait a few minutes before taking the reading (TDS creep).
If using a Deionising filter after the RO, then the TDS reading should be zero at the end point.

The source water was showing >160ppm when I tested it prior to RO filters.... after RO filters it was coming out as 10ppm. I’m going to add on a DI unit onto my DDO RO unit so I can get TDS of 0.

 

[Scrubber_steve]

The source water was showing >160ppm when I tested it prior to RO filters.... after RO filters it was coming out as 10ppm. I’m going to add on a DI unit onto my DDO RO unit so I can get TDS of 0.

Just note down that RO reading. When its eventually starts rising it's time for a new RO Membrane,,,, but don't forget about TDS creep, & wait a few minutes of flow through before taking reading.

 

[Saveafish]

If your input TDS are 100 and you have a good 98% REJECTION rate and your out put should be 2 TDS before the DI stages.

 

[lapin]

Hi again!
I’ve looked into getting DI unit for my current DDO RO unit. I’ve a couple questions though if anyone can help? .........
Does the
TMC V2Pure De-Ionisation Pod (500ml) inc Resin unit fit onto the DDO RO unit
And if so.......
How does it go on/fix in place ?
Thanks everyone x

As per a web site description: To use, simply attach the Pod to the RO unit. Please note that it does not come with additional pipework.
It is an add on unit and will require some tubing and maybe a fitting. From the picture on this site i see the clamps to hold it and some fittings. I would call your stockist and ask.
https://fitfiltration.co.uk/products/de-ionising-pod

 

[ScooterV]

Unless you have very little space I would recommend adding additional canisters. Those "pods" don't hold much and will be exhausted quickly, can't see color changing resin (some do come clear though), and at least to me are a much larger pain to change the resin.

 

[Water Dog]

The source water was showing >160ppm when I tested it prior to RO filters.... after RO filters it was coming out as 10ppm. I’m going to add on a DI unit onto my DDO RO unit so I can get TDS of 0.

How many GPD is your membrane rated for? Do you know the make of your RO membrane?

A 75 gpd Dow Filmtec membrane gets a 98% rejection rate. So at an incoming of 160 tds from the tap, your RO membrane should be producing no more than 4 tds.

10 tds from 160 tds source water means a paltry 93% rejection rate. Seems pretty low for a new membrane IMO.

 

[Emma01]

How many GPD is your membrane rated for? Do you know the make of your RO membrane?

A 75 gpd Dow Filmtec membrane gets a 98% rejection rate. So at an incoming of 160 tds from the tap, your RO membrane should be producing no more than 4 tds.

10 tds from 160 tds source water means a paltry 93% rejection rate. Seems pretty low for a new membrane IMO.

Hi.
Yes, the RO membrane is D-DO. I’ve also got DI unit coming today to put onto the current RO system, hopefully that’ll help TDS reading. If not,.... I’ll have to strip it down, filters, membrane etc and work out what’s going on. It seems nothing goes my way when it comes to my hobby

 

[Water Dog]

Very strange, it looks like D-D uses rebranded Filmtec membranes. A 93% rejection rate seems way out of spec for a new Filmtec membrane. It really should be more like a 98%. Did you buy the unit new? Do you know what your water pressure is?

While the DI unit will get the TDS down to 0, the question is at what cost? Pushing 10 tds water through a DI canister will quickly deplete it costing you substantially more money in DI resin over time. Based on your membrane make, you should be pushing 3 -4 tds though your DI unit, not 10 if the membrane was running to its proper specifications. I would check with the seller of your unit if you bought it new to see if you could get a replacement membrane.

https://www.theaquariumsolution.com/product/3046/155

 

[lapin]

Hi.
Yes, the RO membrane is D-DO. I’ve also got DI unit coming today to put onto the current RO system, hopefully that’ll help TDS reading. If not,.... I’ll have to strip it down, filters, membrane etc and work out what’s going on. It seems nothing goes my way when it comes to my hobby

Im sure it will help. Add it on and let it rip. It will take a few gallons to settle in. I think you will be fine. Only time will tell if its the unit or your TDS meter

 

[Emma01]

Hi . Have let the RO system run for a good 3 hours and I’m glad to say the TDS has come down from 10 to 6Maybe it just needs running, as they’re fairly old water supply pipes. I will still add the DI pod and hopefully that’ll bring down to 0
(I hope!) I’m going to run it for 24 hours and see what happens

 

[lapin]

Sounds like its workin ))

 

[reefwiser]

All water filter tech is the same so one needs to get the proper filters for the task at hand.
Dow Ro membranes are the best. Then just get standard filter cartridges and install Di resin after the RO membranes I generally use two of them for long lasting filtration. Before the membrane you have particle filter housing, The a carbon block and a chloramine filter and in many cases a silcate filter

 

[MSB123]

I have a 150 GPD. 560 TDS in, 6-7 TDS Out pre DI. 0 post DI

 

[lapin]

I gots a 150 GPD (water saver). 8 TDS in 0 TDS out pre DI. 0 post DI