Inline TDS reader

hello all,

granted these are not the most reliable readers nut iv had the following issue.

after many headaches and attempts, and mainly thx to AZ iv been able to get my RODI unit working (or at least i think so) correctly. my inline tds reader shows 130 in the IN line and a nice flat triple zero in the OUT line.

now i store this water in a 100l canister for future use, today i took out the OUT line of my inline TDS reader and dropped in the canister out of curiosity to see what it would read.....it reads 170.

there was some uncleaned water left over (less than half a liter) would this have been enough to foul my water or is the TDS not reading correctly as its measuring "static" water and not water running through its sensors?

I will when im blessed with a little more cash invest in a digital TDS reader but for now.....Thoughts?

 

ya sounds like your container is not clean and has effected the water TDS. However what I would do is take say a plastic cup and run some fresh ro into it and then take a cup of the container water and put the out into the new fresh ro/di water and put the in into the old container water and check the readings again.

 

Inline TDS meters cannot be used portable. They rely on flow past the probe while inserted in the provided tee to work. This is another drawback to them besides not being trult ATC temperature compensated. I never even use mine anymore and I have two of them, they never agree with my COM-100 or AP-1 handhelds.

 

thats what i thought, thx for the replies guys

 

humm interesting!!

What if swiss puts a pump in the bucket.. think that would work. for now

Guess it would not hurt to get a com-100 to do quick checks of ro water(only 60 bucks on a quick check online.. probably find better deal). Personally I do not keep ro/di sitting around in bucket, I run it when I am going to use it the next day or 2 day max. I only have a 135 and a 30gal tank so do not need to have container full at all times.

EDIT and PS wife would not give it a go anyways ha ha ha

 

I have a covered 23 gallon Rubbermaid recycling can for my ATO storage. It is fed from my RO/DI and has float switches set 12" apart so it has to drop 11 measured gallons before it comes on again to refill. It has been in use for over 6 years and has been completely drained and cleaned exactly twice in 6+ years.
When I measure the TDS using my COM-100 is is less than 1.

I also use five 5G clear PET plastic drinking water jugs with plastic caps to store my water change water for months at a time and they never measure over 1 or 2 at the most either.

It does not take much leftover saltwater to contaminate a boat load of fresh RO/DI since new saltwater has a TDS somewhere over 32,000 ppm. It would take a lot of dilution to get that down to even 170 TDS in a 100l container. Empty the container out then do a cleaning with distilled white vinegar to remove any dissolved solids, rinse it well with fresh RO/DI or a jug of distilled water and it should be clean.

Swiss, you will probably want to move your IN probe on the TDS meter to between your RO membrane and your DI filter so you know what your RO membrane is doing. You already know your tap water is 130+/- and it is not going to change significantly but you need to know how well the RO membrane is processing that 130 TDS since it does 90-98% of the treatment. You want to read RO only with the IN and final effluent or RO/DI with the OUT probe. If you had two dual inline meters or one of the three probe models then you could have a probe on the tap water but for now with only two probes the RO and the effluent are your best placements. Also make sure the probes are oriented correctly and inserted all the way into the provided tees so they are as accurate as possible.

It doesn't have to be a high end COM-100, the AP-1, TDS-3 and TDS-4TM can all be had for $20-$25 US and are all temperature compensated and have built in digital thermometers so are very accurate. Thye just don't read down to tenths of a ppm like the COM-100 which I like but I do water treatment for a profession so am kind of anal about it.

 

Hahaha thx for the tips ill move the inline later today. I just used the last of the water in my container and will be getting down to give it a good scrub soon. Of course the day i decide to do this is the day it starts raining after a week of glorious sunshine -.-