Testing RO water

[turbo21]

Troylee just posted in his tank crash thread that he has had 0 TDS readings from his RO and still tested levels of po4 in his water. Is this just faulty TDS readings or have others experienced this? Has anybody else tested their water for the norm stuff when having 0 TDS or are you like me and just say 0 means the water is good?

Bob

 

[blacktang]

always test everything

 

[Troylee]

I need to find that post and edit it but it was .03 not .3 lol... Tds does not
Pick up po4.... With that being said this post has derived "pretty sure" from a comment I made saying that I have noticed a common trend of people running a canister full of gfo on there mixing stations... Anyone here doing this???

 

[Tabasco1]

Are you suggesting testing every ro batch? That seems a bit excessive. Or are you suggesting to test initially?

 

[Troylee]

Just saying po4 can make it's way through a rodi system and most people don't realize it since there tds says zero they assume all is okay.... It's not a large amount and if your not intially filling your tank it shouldn't be a concern... Small amounts like that can and will vanish quickly in a display with gfo or carbon sources etc....

 

[SaraB]

I watch my TDS with an inline meter and then double check with a handheld unit. Yes, I do this weekly when making water.

 

[Troylee]

That's a good practice for sure Sara but have you ever tested the po4??? Tds won't pick it
Up...

 

[Paul_N]

I don't test my RO/DI water. You can be getting PO4 from the container also. I would be worried if I was having issues with high PO4 in m tank and nothing was bringing it down. But if my tank PO4 levels are where I want them (.03-.05) then for me, I'm not really concerned if the water coming out of my holding barrels is registering PO4 levels. With that being said I will test my RO/DI water in my holding barrels just to satisfy my curiosity. Thanks for giving me something else to test......:tongue:

 

[Paul_N]

I have an inline tds meter like Sara and test with every 65 gallon barrel I fill up. I was going to get a hand held because I have heard that the inline are not that accurate. Anyone else hear that?

 

[turbo21]

No problem Paul, we all need to test mor anyways. off to check my po4 levels

bob

 

[Troylee]

There prolly not!!! I know there a pita to calibrate I bought the solution and could not get the
Little screw to budge just ever so slightly to cAlibrate it correctly... Mine is like 10 over what i calibrated it
To the "solution"so if I get a reading higher than 1 I know I got 10 tds coming out... My hand held seems to work okay but I really don't have Anything to make sure it is exact....

 

[SaraB]

I was going to get a hand held because I have heard that the inline are not that accurate. Anyone else hear that?

My inline always shows lower than the hand held, so I only trust the hand held unit.

 

[SaraB]

That's a good practice for sure Sara but have you ever tested the po4??? Tds won't pick it
Up...

I guess I never really cared as I always run GFO on my system.

 

[AZDesertRat]

Phosphates are weakly ionized and will not show up on a hobbyist grade TDS meter in low levels. Good DI resin like Spectrapures SilicaBuster packed correctly in a vertical cartridge with sufficient contact time will get phosphates no problem.

 

[SaraB]

Thanks, I do use nuclear grade DI resin from BRS.

 

[AZDesertRat]

I used to use nuclear grade and semiconductor grade too but there is no comparison. My DI life went from 150 gallons per refill to 1000 gallons per refill and the resistivity went from 17+ megaohms to 18.2 megaohms so much better water. If you have a single DI try the SilicaBuster and if you have dual DI try the MaxCap/SilicaBuster combo, I guarantee after one cartridge you wil never go back to normal prepackaged resins.
Untitled Document

 

[SaraB]

I actually have a 20" DI cansiter that I refill with the bulk bags of resin. Do they sell it by the bag? I didn't see it listed that way.

 

[AZDesertRat]

Yes, on their regular website the list bulk resin refills.
BULK DI RESIN

 

[Tabasco1]

The in line TDS meters are pretty much always testing right? You just look at the reading? Or do they have to be engaged? I was talking about individually testing the final water product. Are people testing that with every batch? If so, I will probably be a failure.

 

[AZDesertRat]

You have to push a button to turn them on each time and they shut off automatically to conserve battery life. You must also slide a switch form one probe setting to the other to see both TDS readings.


I prefer handheld TDS meters myself but the handhelds are a good guide to go by. The biggest drawbacks with the inlines are they are not temperature compensated and they cannot be used portable.
The inline probes are actually sensing air temperature and not water temperature so can vary quite a bit if the air and water vary by much.
The probes also depend on flow past the probe elements so must be inserted in the provided tee and rotated to the correct orientation. You can't just pull one out and dip it in the water, it won't register correctly.

I do use my inlines on my MaxCap system every time I am checking TDS but I occasionally pull the COM-100 handheld out to double check readings and get an idea of the variance. They never agree but are usually within 40-50 0n the tap water TDS (my tap TDS is about 650 so thats close enough for a guide, within 2 or 3 on the RO only TDS (my RO only TDS is 2.5-3.5 on the COM-100 handheld) and within 1 or 2 on the DI readings which are 0 on the handheld. Close enough to see if something is drastically wrong.

My RO/DI is hooked up to a 23 gallon rubbermaid trash can with a solenoid and float switches so is automatic and I am not there every time it makes water but I try to do a few quick checks every week or two if I happen to see it making water.