Rodi water storage (1 Viewer)

[Team Turtle]

So I use two, 44 gallon brute trash cans for my rodi water storage...fill both with fresh water and mix my salt in one when doing water changes on my 160. After that water change i rinse the can, let it dry and the next day fill back up with fresh water. The water then sits for 2-3 weeks until i mix salt water again...the other can get's used throughout the days for my top off and i fill as needed. Well i got a new tds pen from inkbird for my fresh water planted tanks and decided to double check the tds meter on my rodi unit. Filter says 0. Pen says 0 in can that gets used regularly. Test the second can that has been sitting for 3 weeks now and it says 3110. I test again...3110. Other can 0..test other fish tanks and they range between 113 and 150..again, fresh water planted tanks. Back to brute can...3110. Question would be. Is the trash can leaching something into the water? My tds before the rodi averages 550 so at a loss here. I could rotate which one i use but if it's leaching something I'm not using it anymore. Will note i bought both cans at the same time from home depot

 

[foos]

TDS probes are conductivity probes. RODI water does not conduct electricity since there are no ions in it. Salt makes water conduct more, the more salt there is. TDS meter reading means something got in the water. What it is or how it got there.

If it is a food safe brute, you could taste it. You would not be the first person to get salt and RODI buckets mixed up.

 

[Team Turtle]

TDS probes are conductivity probes. RODI water does not conduct electricity since there are no ions in it. Salt makes water conduct more, the more salt there is. TDS meter reading means something got in the water. What it is or how it got there.

If it is a food safe brute, you could taste it. You would not be the first person to get salt and RODI buckets mixed up.

It's all fresh water though. Have not mixed salt yet.

 

[Team Turtle]

It's all fresh water though. Have not mixed salt yet.

Unless just rinsing it out is not good enough and there is some residue from last time i mixed salt?

 

[jrounding]

Unless just rinsing it out is not good enough and there is some residue from last time i mixed salt?

I just rinse my brute trash can after mixing coral pro salt and there’s some white chalky residue building up on the container. Obviously using soap is out of the question, but I don’t store water for long periods so I don’t worry. It’s reasonable to think that once you fill up again that residue would dissolve into the water. Did you check the salinity of the water? The problem with TDS is it just measures particles. You have no idea what those particles are that it is reading. Also these cans don’t have the best fitting lid so maybe it’s stuff from the air? Either pull a sample from below the water line with a turkey baster, pour in a cup or stir the tank and re-take the reading to see if it drops. It could be a bunch of solids sitting on the surface and it’s not a continuous TDS that’s throughout the container. Just some ideas of what to check. Obviously it could be the plastic as you first mentioned.

 

[Team Turtle]

I just rinse my brute trash can after mixing coral pro salt and there’s some white chalky residue building up on the container. Obviously using soap is out of the question, but I don’t store water for long periods so I don’t worry. It’s reasonable to think that once you fill up again that residue would dissolve into the water. Did you check the salinity of the water? The problem with TDS is it just measures particles. You have no idea what those particles are that it is reading. Also these cans don’t have the best fitting lid so maybe it’s stuff from the air? Either pull a sample from below the water line with a turkey baster, pour in a cup or stir the tank and re-take the reading to see if it drops. It could be a bunch of solids sitting on the surface and it’s not a continuous TDS that’s throughout the container. Just some ideas of what to check. Obviously it could be the plastic as you first mentioned.

I checked the salinity like you said...read 0.01 then 0...stirred everything and read 0...but for grins i checked the tds of a fresh batch of salt and it read over 4000. So guessing you and foos are right. Residual salt. The other can has never had salt in it so what I'm going to blame anyway.

 

[jrounding]

I checked the salinity like you said...read 0.01 then 0...stirred everything and read 0...but for grins i checked the tds of a fresh batch of salt and it read over 4000. So guessing you and foos are right. Residual salt. The other can has never had salt in it so what I'm going to blame anyway.

It seems like the most logical thing to me. One other thing is salt water may cause a TDS meter to read something whacky since it’s readings are based on conductivity. Water itself isn’t conducive, but salty water is quite conductive.

 

[soymilk]

i read you're never suppose to use a tds meter on salt water. It contaminates the sensor

 

[Team Turtle]

i read you're never suppose to use a tds meter on salt water. It contaminates the sensor

Once or twice won't hurt but yes could cause corrosion on probes