TDS Creep

[Emmanuel75]

Ok, so today I was about to do another small water change as to continue to keep my parameters in check. I test my TDS from my RODI about every other week to make sure I'm not adding Phosphates into my system. My phosphates are at a .04. Due to a faulty API test kit, I didn't know that my Nitrates were at an alarming 25ppm (THANKS LFS)! So, my plan to gradually fix my numbers is to do small 6 gallon water changes daily until they are back in line then revert back to weekly 10%.

I tested my RODI water and it has crept up to 5ppm. I have only had my RODI unit for a month, however when I purchased the RODI it tested at 1ppm. All cartridges and resin was brand new, but I figured that 1ppm should not have been detrimental. I'm starting to suspect the TDS meter now because testing my tap water it gives an error message. However testing after membrane it tests at 23ppm, but after two stages of DI it tests at 5ppm? BTW it is a 6 stage Titan Water Pro RODI unit. I've checked the connections, flushed the membrane, I'm not sure what else to try. I don't have another meter or I'd try a different one incase this one is faulty.

Any other suggestions? I'd like to get my to my water changes but don't want to poison my system more in the process.

[b0bab0ey]

Are you saying your RODI output is 5 and your waste water (RO) is 23? That's not too bad IMO and probably not your problem. But my RODI is 6 months old and still reading 1. Have you ever tested your tap water? What reading do you get there?

[briankmarsh1980]

if everything is brand new you should be reading 0 out of the unit.....

I would post your question here to get some professional help

http://reefcentral.com/forums/forumdisplay.php?f=229


EDIT: the TDS coming into my unit runs between 800-900ppm out of my membrane it reads 13-15 and 0 out of the DI's and as soon as it jumps to 001 I change my DI this happens about every 400gallons or so

[shifty51008]

I would deff. get a calibration fluid for your TDS meter, if your getting an error on your tap water, you either have very horriable water or the meter is wrong.

calibrate that 1st then check the water and let us know.

[Buckeye Hydro]

Need a little more info to help you.

First we need 3 TDS readings - you've provided 2:
Tap water TDS: ??
RO water TDS: 23 PPM
DI water TDS: 5 PPM

What is your water pressure at the membrane when the system is running?

Russ

[Emmanuel75]

It is weird. I dumped my container and rinsed it out. After letting it run, I refilled my container again and it now tested at 0tds! I tested it again by testing water from the membrane then again the DI. So, I probably had something in the container that was throwing off the meter.

I'm still getting the calibration fluid just in case.

Thanks guys for your help!

Sent from my Nexus S using Tapatalk

[Buckeye Hydro]

In general, its not good practice to meause the TDS of your DI water directly from a storage container.

Remember that you are reading in parts per million, so even the slightest "contamination" in your storage container will skew the reading.

Test the TDS of your tap water using a clean glass container.

Russ

[Dbondaruk]

Ok this a old tread but I had a question. I been battling hair algae for couple months. My rods was reading 0 out of the du resin to I never figured to check anything else. Today I decided to check my TOP OFF bin and the TDS was 580. I saw some dust in the bottom container. So now I am cleaning the top off bin. It's a brute 34 gallon can. I went to my garage and checked my rodi mixing station. It had about 5 gallons of water that sat at the bottom for like 2 weeks due to mixing station pump doesn't get all water out of containers. I filled it up overnight with rodi water. Water coming from the unit 3 TDS. Out of the du resin 0. Now why is my storage container showing me that I have 56 TDS in the bin. Should I dump it out and clean bin.

[Buckeye Hydro]

You'll never get that type of storage container absolutely clean, and if you do, it wont stay that way for long

[alf1096]

Tagging along I too use trash cans but don't have a way to test the tds in the can because I only have an inline meter.

[Buckeye Hydro]

Most people don't test the TDS in the reservoir...

[Dbondaruk]

Originally Posted by Buckeye Hydro

Most people don't test the TDS in the reservoir...

Ok thanks I found out why i had high tds in my top off resovoir. I pump water from my garage that's about 60 feet through a 1 inch pvc pipe. So here is what happens. I usually flush about 2 gallons of water at my sump when I switch between salt water and rodi water. My mixing change station is in the garage as well as the rodi machine. My top off container is next to sump. I pump saltwater and rodi water thru the same pipe to sump. When I fill my top off container that's where the tds comes in. A little bit of saltwater still remains in the pipe. I filled top off bin full. Tds shows 160. When I just started filling bin tds showed 600. But the water coming from the garage shows 2 tds. Coming out the rodi machine is 0. I keep it maintained very well.

My question is. Is that a major problem that a little saltwater gets tracked into my top off bin throwing the tds meter off. I did a sample and it take just a little bit of saltwater to throw off a gallon of water with 0 tds. I tested by adding a tablespoon of salt water and it threw the reading off. Thanks for the help fellas.

[Buckeye Hydro]

Seawater reads about 35,000 to 45,000 ppm.

When you top off you are replacing pure H20 that evaporated, so the textbook answer is that pure H2O is what you should top off with. Considering you have a 34 gallon reservoir, I don't think "a little bit" of saltwater in there would be much of an issue. I guess it depends upon what "a little bit" is. (Had a Bill Clinton flashback for a second there).

As long as you keep an eye on the salinity in your tank over time, you should be OK.

Russ

[Dbondaruk]

Originally Posted by Buckeye Hydro

Seawater reads about 35,000 to 45,000 ppm.

When you top off you are replacing pure H20 that evaporated, so the textbook answer is that pure H2O is what you should top off with. Considering you have a 34 gallon reservoir, I don't think "a little bit" of saltwater in there would be much of an issue. I guess it depends upon what "a little bit" is. (Had a Bill Clinton flashback for a second there).

As long as you keep an eye on the salinity in your tank over time, you should be OK.

Russ

Ok thanks a lot for the info.