TDS meter

[kbsharp]

Hi Guys!!!

How are you today? could you help me understand my TDS says it has 2% accuracy, what doest that mean?

My RODI unit is brand new the first time i tested it was 0ppm now its 0002ppm.

Any help please?

 

[Ron Reefman]

My thinking is if you had a TDS reading of say 100ppm. Then the 2% accuracy would mean it could be anywhere in the range from 98 to 102ppm.

So your reading of 2ppm could be in the range of 1.96ppm to 2.04ppm. Either way that's a good reading. Some reefers aren't happy with anything but zero ppm and others, like me, think any small number is probably OK. The fact of the matter is, if you know what the contaminate is and it's harmless, a TDS of 50 would be OK. But if the contaminate is copper, 1ppm could be bad.

 

[kbsharp]

My thinking is if you had a TDS reading of say 100ppm. Then the 2% accuracy would mean it could be anywhere in the range from 98 to 102ppm.

So your reading of 2ppm could be in the range of 1.96ppm to 2.04ppm. Either way that's a good reading. Some reefers aren't happy with anything but zero ppm and others, like me, think any small number is probably OK. The fact of the matter is, if you know what the contaminate is and it's harmless, a TDS of 50 would be OK. But if the contaminate is copper, 1ppm could be bad.

That was my thinking thank you for clearing that up for me.

So should i test the 2 ppm water for copper? Or how does it work I've see like strips how does that work?

 

[Ron Reefman]

If you are starting with 'normal' city water, IMHO it's unlikely that whatever is the contaminates would be harmful after going through and RO. And especially if you also us DI.

I'm curious, what is the TDS of the source water you use?

If you are on a well or have really bad city water (like Flint, MI situation with lead) I'd consider getting a couple of tests done. One for the source water to see all that was in it at the start and then what's in it after your RO/DI.

My city water runs a TDS of 350ppm and my RO/DI takes it to zero. But I have a fairly crazy RO/DI system. I would never have done this if I had to pay the price it sold for new. But a friend who had to give up his tank had bought it used and he gave me a steal of a deal. Before I had this system, my 'normal' RO/DI system would start at zero and when the RO only level got up to 20, I'd replace the membrane. The DI always took it down to zero. Before that, we were on a well and I gave up on DI as I had to change it far too often. And I regularly used RO water with a TDS of 10 to 20+ ppm. And I never had any water related issues with my tank.

 

[kbsharp]

If you are starting with 'normal' city water, IMHO it's unlikely that whatever is the contaminates would be harmful after going through and RO. And especially if you also us DI.

I'm curious, what is the TDS of the source water you use?

If you are on a well or have really bad city water (like Flint, MI situation with lead) I'd consider getting a couple of tests done. One for the source water to see all that was in it at the start and then what's in it after your RO/DI.

My city water runs a TDS of 350ppm and my RO/DI takes it to zero. But I have a fairly crazy RO/DI system. I would never have done this if I had to pay the price it sold for new. But a friend who had to give up his tank had bought it used and he gave me a steal of a deal. Before I had this system, my 'normal' RO/DI system would start at zero and when the RO only level got up to 20, I'd replace the membrane. The DI always took it down to zero. Before that, we were on a well and I gave up on DI as I had to change it far too often. And I regularly used RO water with a TDS of 10 to 20+ ppm. And I never had any water related issues with my tank.

Well my tap water TDS is excellent its 57ppm as i live away from the city. Since its so low i expect 0 TDS i have a RODI filter