Aqualifter raising TDS in topoff water?!?

[waverz]

I recently setup a new ATO system and wanted to verify everything was functioning properly and I wasn't getting TDS creed in my reservoir.

I was VERY surprised at what I found.

About my setup:

I have a 1/4" line coming directly from my RODI to a 120v NC solenoid that is opened for 1 hour every other day. This solenoid feeds a 2.5 gallon reservoir that is equipped with a float valve. From there I have an aqualifter pump which is controlled by a float switch inside my sump.

I was curious to see if I was getting TDS creep in the reservoir so I decided to pull a sample. The reservoir was half empty and impossible to reach with the tds meter so I decided to use the aqualifter to pull the sample from the reservoir.

The water that was sitting in the aqualifter had a TDS of 86ppm!
I let it run for about 5 seconds, tested again and measured 9ppm.

Let it run for 5 more seconds and then read 0.

I let everything sit for the day and tested again and got nearly the same results.

Basically whatever water that sits inside the aqualifter pump get contaminated before it's pushed into the tank. While it is less than .5 oz of water it still is something I don't want pumped into my tank 24/7.

Anyone else running an aqualifter want to compare results? I might be switching top off pumps.

 

[Timidfish]

I run a aqualifter but dont have any way to test my tds coming and going that way. Just off my rodi unit. I test my phos in my holding tank and it reads zero and in my sump, display and ato tank is all zero. But doubt that tells you anything you want to know sorry.

 

[disc1]

The TDS of the water in your bucket isn't very important. The water has had time to sit and dissolve some gasses like CO2 out of the air.

You're using TDS wrongly. TDS is a good way to make sure your RODI filter is working well. If it is then the water coming out should be at 0. But you cannot use TDS to gauge the quality of water for your tank after that. Not all dissolved solids are created equal.

Think about this, the TDS in your tank with the salt dissolved in the water is 35,000ppm or so.

 

[waverz]

I understand what the TDS meter is for but if I have water with 0 TDS going into a pump and not coming out at 0 doesn't that mean there is some sort of contamination happening?

It seems to me that the rubber diaphrams of the pump might be leeching something into my top off water.

How else would the TDS get so high just from sitting inside the pump?

 

[Timidfish]

Well I just remembered this. In my inline tds meter it actually states that any reading taken immediately after water starts to flow is a false number because it is the water that has been sitting and any water just sitting is going to get tds from the air. It states to let the water run for about 30-45 seconds prior to any usable reading. And I can confirm on start up it read 30 or so but within about 10 seconds its at zero.

 

[waverz]

Well I just remembered this. In my inline tds meter it actually states that any reading taken immediately after water starts to flow is a false number because it is the water that has been sitting and any water just sitting is going to get tds from the air. It states to let the water run for about 30-45 seconds prior to any usable reading. And I can confirm on start up it read 30 or so but within about 10 seconds its at zero.

How is there air inside your 1/4" lines that are full of water?

The water sitting in my reservoir exposed to "air" still reads 0.

 

[Timidfish]

I dont know how just know it's what my instruction manual said. And it is somehow backed up via my readings. Maybe ir works it way backwards through the line going into the sump. Like I said its just what I read and have seen. Not really sure why or how or anything like that. Sorry I can't be more help.