TDS Education

[Cscultho]

I want to get some expert opinions on TDS measurements. Im not very clear on what we are looking to achieve for TDS water readings before we put water in our reef tanks. Ive received different opinios as to what it should be but i want to have a broader discussion for my education.

Im in the middle of a Dino battle and many reefers are being very helpful in educating me on how to battle the Dino-Demo so to help expand my knowledge i want some TDS help.

I was topping off my ATO and i happened to measure the water with my hand held TDS meter and found the TDS to off the charts 176! This was in my ATO. So i tested the water coming out of my RO/DI system right at the outlet and it measured ZERO TDS?? Ok so my source water seems good but for some reason my ATO is 176 so i decided to get rid of the bad water and start filling up my 5 gallon HOME DEPOT bucket to replenish the bad ATO water. As the Home Depot buck was slightly filled i measured the TDS and it was 15!!! I just measured my source water as it exited the DI and it is ZERO????? I switched buckets to my old RED SEA SALT bucket that measure around 15 TDS!!!! what the heck?? I decided to fill a small plasitc cup half way full and it measured ZERO TDS????!! I filled part of my 45gallon Rubber Maid trash can and 10 TDS??

My RO/DI water is ZERO as it comes out the tubes from the system but immediately shoots up when it hits the buckets???!! For the exception of the small plastic cup which read ZERO.

Has anybody else experience this? Does anybody do a reading of their water in their containers before it goes into their tanks??

Do I need to find a new container to mix my water in because i think the plastic is causing a spike in TDS?!

This is probably the big source of my Dino misery?!!!

 

[DSC reef]

This is interesting, I'm following along.

 

[Randy Holmes-Farley]

The plastic itself isn't likely boosting the TDS of the stored water that much. But contaminants in the bucket (dried salts from water that was previously in it, even if rinsed, for example) or salty dust/spray that hits it can easily do so. Skimmers and popping bubbles can put out lots of very fine salty droplets to the air.

TDS is properly used as an indicator of the correct functioning of an RO/DI. It is not a suitable measure of whether water is good or bad for a reef tank becaase for that purpose, it depends entirely on what is in the water. 35,000 ppm TDS water can be fine to add to a reef tank (e.g., natural seawater) and 1 ppm TDS water isn't if it is primarily copper.

FWIW, I seriously doubt the ions getting picked up by your RO/DI water before use are "causing" dinos. I can't really think what could be added to the new water (any water) that would cause a dino problem.

I discuss what the concerns are with tap water here:

Aquarium Chemistry: Tap Water in Reef Aquaria ? Advanced Aquarist | Aquarist Magazine and Blog
http://www.advancedaquarist.com/2004/1/chemistry

and I discuss exactly what TDS means here:

What is TDS? by Randy Holmes-Farley - Reefkeeping.com
http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.htm

 

[Cscultho]

The plastic itself isn't likely boosting the TDS of the stored water that much. But contaminants in the bucket (dried salts from water that was previously in it, even if rinsed, for example) or salty dust/spray that hits it can easily do so. Skimmers and popping bubbles can put out lots of very fine salty droplets to the air.

TDS is properly used as an indicator of the correct functioning of an RO/DI. It is not a suitable measure of whether water is good or bad for a reef tank becaase for that purpose, it depends entirely on what is in the water. 35,000 ppm TDS water can be fine to add to a reef tank (e.g., natural seawater) and 1 ppm TDS water isn't if it is primarily copper.

FWIW, I seriously doubt the ions getting picked up by your RO/DI water before use are "causing" dinos. I can't really think what could be added to the new water (any water) that would cause a dino problem.

I discuss what the concerns are with tap water here:

Aquarium Chemistry: Tap Water in Reef Aquaria ? Advanced Aquarist | Aquarist Magazine and Blog
http://www.advancedaquarist.com/2004/1/chemistry

and I discuss exactly what TDS means here:

What is TDS? by Randy Holmes-Farley - Reefkeeping.com
http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.htm

Randy thanks for the feedback. i will read your posts and get educated.