Acceptable TDS range

Rscott · Jul 9, 2019

Hey all,

So my RODI unit brand new from BRS and only has 150 gallons through it is already reading 2 TDS.
I have my town water report and we dont even use chloramines. We have very good water here.

Whats up with that?

What is an acceptable range of TDS?
Thanks

redfishbluefish · Jul 9, 2019

What BRS unit do you have?

What is the TDS of raw water? A quality membrane will have a 98% or better reduction in TDS out of RO only.

And the comment about "town water report", I assuming you're not on well water???

You should be at 0 TDS.

flyline · Jul 9, 2019

Maybe try back flushing unit

KStatefan · Jul 9, 2019

What is the TDS going into the DI filter?
What type of DI system is it?

Rscott · Jul 9, 2019

BRS 5 stage premium
Yes town water

BeejReef · Jul 9, 2019

How does the DI resin chamber look? 150-200 gallons is about when I start to see TDS >0. I use the mixed bed resin and my water seems to deplete one of the resins before the other, so it doesn't necessarily appear exhausted.

Jon Fishman · Jul 9, 2019

Rinse a clean glass really well with the RODI and then fill, and test again. I get 1-2 TDS from glasses sometimes having soap film etc.

But either way, I wouldn’t be too worried about 2 TDS

rcpalmer1 · Jul 9, 2019

The DI resin should take it down to 0. When I first start mine(I don't have the flush valve) I may get 50 out of the membrane. It will slowly drop and normally runs 3-4. I never get more than 0 coming out of DI unless in is used up and needs to be replaced.

Rscott · Jul 9, 2019

I

William DeCoursey said:
How does the DI resin chamber look? 150-200 gallons is about when I start to see TDS >0. I use the mixed bed resin and my water seems to deplete one of the resins before the other, so it doesn't necessarily appear exhausted.

Looks like it always does I guess?
It doesn’t come with color changing resin so I would say it looks like it did when I set it up

I asked BRS when I bought this how frequent I needed to change filters and they told me every 3000 gallons not every 300

What number TDS is bad?

W1ngz · Jul 9, 2019

Any TDS over 0 measured at the output is 'bad'. 1 means you should be changing the DI resin. 2 means you should have changed it a few weeks ago. There's no way of knowing exactly what element or compound that 1 or 2 is, so you're currently putting something unknown into your reef. If you're not measuring in-line, and measuring in a glass or bucket or something then you're likely to have a TDS of under 5 just from normal stuff in the air and whatever was in the bucket to start with.

The filters that BRS is talking about are more than likely the sediment and carbon filters. Your DI resin will have to be changed or refilled more frequently than the others.
Depending on the source water, mixed resin can deplete pretty quick if it's exhausting one of the two in the mix. A solution to that might be 2 DI stages with anion and cation resins.

Do you have the premium or the premium-plus 5 stage? One does and one doesn't have the TDS meter directly in-line with the output.

Rscott · Jul 9, 2019

W1ngz said:
Any TDS over 0 measured at the output is 'bad'. 1 means you should be changing the DI resin. 2 means you should have changed it a few weeks ago. There's no way of knowing exactly what element or compound that 1 or 2 is, so you're currently putting something unknown into your reef. If you're not measuring in-line, and measuring in a glass or bucket or something then you're likely to have a TDS of under 5 just from normal stuff in the air and whatever was in the bucket to start with.

The filters that BRS is talking about are more than likely the sediment and carbon filters. Your DI resin will have to be changed or refilled more frequently than the others.
Depending on the source water, mixed resin can deplete pretty quick if it's exhausting one of the two in the mix. A solution to that might be 2 DI stages with anion and cation resins.

Do you have the premium or the premium-plus 5 stage? One does and one doesn't have the TDS meter directly in-line with the output.

It’s the premium plus with the TDS

W1ngz · Jul 9, 2019

So you're measuring the output directly.
Your filters are fine.
Replace or refill the DI resin and flush the membrane.

KStatefan · Jul 9, 2019

What is the TDS of the source water and what is the TDs of the water going into the DI stage?

madweazl · Jul 9, 2019

Until you test the TDS of your tap water, there really isnt any way for us to provide any useful feedback.

Rscott · Jul 9, 2019

W1ngz said:
So you're measuring the output directly.
Your filters are fine.
Replace or refill the DI resin and flush the membrane.

After 150 gallons your telling me i need to replace the resin , i hope your kidding

Rscott · Jul 9, 2019

madweazl said:
Until you test the TDS of your tap water, there really isnt any way for us to provide any useful feedback.

according to the IN side of the TDS, its 3

madweazl · Jul 9, 2019

Rscott said:
according to the IN side of the TDS, its 3

That is after the RO membrane.

Edit: something like this can be used to check your source water. With that info, you can determine if there is an issue with your RO membrane and further troubleshoot. Also worth double checking the lines to make sure everything is connected properly.

Rscott · Jul 9, 2019

madweazl said:
That is after the RO membrane.

It must be because the DI part is separate

dbjonesjr · Jul 9, 2019

madweazl said:
That is after the RO membrane.

Edit: something like this can be used to check your source water. With that info, you can determine if there is an issue with your RO membrane and further troubleshoot. Also worth double checking the lines to make sure everything is connected properly.

You can temporarily remove one of the probes on the RO/DI system to measure the TDS as well. Just pull the probe out and dip it in a cup of source water!