RO System TDS

[Vitor]

Hi all,
My tap water runs at around 400/450 TDS. No idea what that is, I do know though the water is very soft. So KH is 0 and GH is like 1.
My RO System is supposed to be a very good one. It is commercial, made for shops. I don't think you can find it outside of europe, but it is the Blue Pure Premium Pro from Blueclownfish. Makes a lot of water and has 5 stages:
Sediment filter
Carbon GAC
Carbon CTO
2 membranes
1 resin

I used to be able to lower it to 1 tds. I don't know what the tap was at then. But at the moment I can't seem to lower from 20-30 tds. And this is making me a little worried. Is there anything that RO systems can't remove from the water that could be affecting my reads? I tested now with two meters and results come at the same.

 

[Justfebreezeit]

If you are reading it from a bucket or storage container that could add tds.

 

[Vitor]

If you are reading it from a bucket or storage container that could add tds.

Nope. Inline TDS from the RO machine tubing and from a clean cup with a pen

 

[salty joe]

your DI resin might be exhausted.

I would get a dual inline TDS meter and read the RO water as well as the RO/DI water. The first gallon or so of RO water will be high in TDS. Dump it until the TDS reads blow 5, then run it through the DI resin. The RO/DI water should read 0. Your DI resin will last a lot longer.

 

[Vitor]

your DI resin might be exhausted.

I would get a dual inline TDS meter and read the RO water as well as the RO/DI water. The first gallon or so of RO water will be high in TDS. Dump it until the TDS reads blow 5, then run it through the DI resin. The RO/DI water should read 0. Your DI resin will last a lot longer.

I think I will be doing that. Getting another resin stage and see if it solves my problem. Thanks!

 

[KStatefan]

I would suspect your DI is exhausted also.

It helps to have TDS numbers in three locations to diagnose problems. Source water, Pre DI and Post DI.

 

[Vitor]

I would suspect your DI is exhausted also.

It helps to have TDS numbers in three locations to diagnose problems. Source water, Pre DI and Post DI.

Thanks. DI is new, replaced 2 days ago. It improved the TDS (lowerd from 45 to 20 ish) but still, not enough. Wonder what changed, used to be able to get 1 TDS

 

[KStatefan]

Thanks. DI is new, replaced 2 days ago. It improved the TDS (lowerd from 45 to 20 ish) but still, not enough. Wonder what changed, used to be able to get 1 TDS

What is the TDS going into the DI?

 

[Vitor]

What is the TDS going into the DI?

450 now. before when I used to be able to get 1 tds from the RO system I never bothered measuring

 

[KStatefan]

450 now. before when I used to be able to get 1 tds from the RO system I never bothered measuring

If it is 450 going into the DI then your membrane is shot.

 

[Vitor]

If it is 450 going into the DI then your membrane is shot.

what do you mean by shot?
to be clear, this is not going into the DI. This is from the tap, it goes through different stages until it reaches the 5th. I atm only measure from tap and after the RO (so final product). I will try and get more readers so I can control different stages of it.
And thanks

 

[KStatefan]

what do you mean by shot?
to be clear, this is not going into the DI. This is from the tap, it goes through different stages until it reaches the 5th. I atm only measure from tap and after the RO (so final product). I will try and get more readers so I can control different stages of it.
And thanks

I meant it was no good but that was with your first answer that 450 was going into the DI. Need to have both to determine how your membrane is working.