New ro unit and tds issues

Low water pressure can cause poor rejection rates on RO membranes, may be worth the effort to install a gauge there. I leave mine installed right before the RO and this helps me judge when to change my prefilters, when I see a pressure drop it is time to change them.
 
scottwhitson said:
Low water pressure can cause poor rejection rates on RO membranes, may be worth the effort to install a gauge there. I leave mine installed right before the RO and this helps me judge when to change my prefilters, when I see a pressure drop it is time to change them.
Click to expand...

Yeh I will get one. The unit is installed tight next to mains in and the unit has a booster pump fitted. Would the booster pump not be suppling the pressure required?
 
Seems like a lot of time money and work for 3 parts per million parts, and if lucky, maybe they were good parts, or maybe the checking tools are crap.

I seen mine right after making water go 1-2-3-2-3-2-1-1-2-1

It's only when it goes 1-2-3-4-5-6-7.....I check Resin and filter.

I doubt 3ppm (if it's really that) makes really any difference.
 
Uncle99 said:
Seems like a lot of time money and work for 3 parts per million parts, and if lucky, maybe they were good parts, or maybe the checking tools are crap.

I seen mine right after making water go 1-2-3-2-3-2-1-1-2-1

It's only when it goes 1-2-3-4-5-6-7.....I check Resin and filter.

I doubt 3ppm (if it's really that) makes really any difference.
Click to expand...

The main thing is he will burn through DI resin alot faster than if his RO was performing they way it should so in the long run it will be cheaper to have it working properly. I am surprised when I see people just accept things that dont work the way they should.
 
fishkeeprian said:
Yeh I will get one. The unit is installed tight next to mains in and the unit has a booster pump fitted. Would the booster pump not be suppling the pressure required?
Click to expand...

It probably is but maybe there is a restriction somewhere in the system, I.E something stuck in a passage from the manufacturing process. Only way to know is with a gauge and then you can watch when you need to change prefilters as well.
 
If the waste pipe and flow restrictor are in check, what is also worth checking is the line pressure. Is this kit coming with a pump & gauge?

I also suffered from high TDS issues due to low mains pressure < 35psi and with the pump added = 80 psi the issues are gone.

The next thing was DI resin was pretty much ineffective with silicates = SiO4 causing diatom outbreaks with every water change, specific silicate eliminating resin after a standard DI resin resolved the issue. Hard to say but I seem to have now 7 stage RODI unit with a T and re-mineralisation line for the family ;)

BR,
M
 
If you see 271ppm after the membrane and before DI it means the membrane is not functioning properly.

I get 370 from the mains, 20-30 before DI and 0 after DI (silicates for whatever reason still show up on the test kit even though TDS is 0)

If the pressure is above 35psi and the plumbing is right I would call for a faulty membrane.

BR
M
 
fishkeeprian said:
OK now the readings are;

In is 238ppm
Before Di is 8ppm
After is 2ppm
Click to expand...

Did you actually have the system hooked up backwards this whole time or just tapped the wrong lines for those readings?
If you did have it switched the whole time that would explain a lot.. :)

When you are taking readings of the 2ppm water are you letting it run/drain for a couple minutes first then filling up a CLEAN glass and immediately sampling as soon as you get like 2cm in the glass?
 
mcgyvr said:
Did you actually have the system hooked up backwards this whole time or just tapped the wrong lines for those readings?
If you did have it switched the whole time that would explain a lot.. :)

When you are taking readings of the 2ppm water are you letting it run/drain for a couple minutes first then filling up a CLEAN glass and immediately sampling as soon as you get like 2cm in the glass?
Click to expand...

It's been hooked up perfect. I just tested the water wrong that one time. When I start the unit up after a 10min flush it normally starts at around 4/5ppm then after a couple of litres it runs down to 2ppm but will go no lower. Once its hit 2ppm I tested the water in a clean cup as you say.

I worked out I'm get a 96.4% rejection rate from the membrane is that right? Why won't it zero out?
 
Don't take reading from glass or cup....
Put your meter in the holding tank and read.....bet ya it's zero.
The larger sample for me always reads 1,2,3,2,1,1,2,1 and the cup reads, 5-7.


The things that cause small variation is cheap meter, unclean probes cups or small sample sizes. Also caps that are not tight can give the same result.

Be happy with 2 TDS, use for a month or two, check each time ya make water.

I am happy with things when they are producing what I need, your reject rate for incoming is fine.
 
Sorry but 300-400 at the source is not that high to see anything but 0 at the output...

What is your DI cartridge? Is it a tube with 2 blue caps which is typical here in the EU? Make sure you load it full and tight so that no water passes through the gaps when you lay it horizontal. It has to be packed tight.

From 300-400 at the source you get 0 even with a cheap membrane and DI resin.

BR,
M
 
Most meters are not that accurate.
But of course, feel free to work that TDS to zero.
I settled for 1-3 ppm, 27 yeas ago and never had a problem.
Actually, my corals seemed to do better in the 1-3ppm range.
It's like chasing PH, ya I want 8.3, but I will settle for 7.8
 
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