Salt treatment and testing

[aarhud]

Hey guys,

I'm sick (Ate some bad seafood) and I was messing around testing my tanks.

One tank kept making the meter flash x10, and I could not figure it out. Finally realized the only tanks giving insane high TDS readings were the ones I treated for ich using salt. I basically siphoned all of the water out of these tanks and refilled. On the 29 gallon tank I did a 100% (as close as possible), 50%, and 50% water change. How is the TDS still so high?

 

[dw1305]

Hi all,

How is the TDS still so high?

You only need a small amount of salt (NaCl) to raise the conductivity (TDS). You will need to carry on with the water changes for some time before the conductivity declines.

cheers Darrel

 

[gerald]

One teaspoon of salt in 10 gallons will raise the conductivity about 300 uS. When you added the salt, was it completely dissolved in water before you poured it in the tank? If you put salt crystals directly in the tank, some of it may have settled into the gravel and not mixed into the water column until you did a water change.

 

[aarhud]

I added 3 tablespoons per 5 gallons, directly into the tank. Looks like I'll have a lot of water changes to get it out....

Thanks all.

 

[aarhud]

Another 90% water change on the 29g and I'm down to 395 microS. I'm glad I had the meter, I totally overlooked that the salt could raise the conductivity that high and be so difficult to get out.

Does dissolving the salt in water prior to adding it make it easier to remove later?

 

[gerald]

3 tablespoons per 5 gallons, >> approx 5400 uS conductivity ... IF it all dissolved evenly throughout the tank. What might have happened, unless you have an undergravel filter, is that some of the salt crystals sunk into the spaces between the sand/gravel and dissolved there, and didn't mix into the water above. Unless you have strong current, the dense salty water in the gravel can stay there for many weeks or months before it slowly equilibrates with the less salty water above (solar pond principle). Try sucking some water out of the deepest part of the gravel with a pipette or baster and see if the conductivity is any higher than the water above the substrate. Its probably all mixed by now, after a couple refilling events.