Need help on water chemistry

oldfishman · Dec 18, 2018

I have been making top off water with TDS of 0 since the start of my tank 9 months ago. I always check my water from my RO/DI unit two or three times to be sure the TDS is 0 before adding to my reserve. I had been checking my top off reserve once a month to see that the TDS is 0. Well two days ago I made 4 gallons of refill water for the reserve and checked to be sure it was 0 TDS. Yesterday I checked my reserve and the TDS was 762...I checked it 3 times 762. I have no idea what would have contaminated my reserve water or when. I checked my calibration on my TDS meter and it is working correctly.
I think this may explain why I suddenly noticed some hair algae in the tank, which I have taken care of. I originally associated the hair algae with some new Zoia frags. I am know guessing it was the water.
I checked all my parameters with my API test kit and API test strips all are good.
My tank is only a JBJ 28 so today I changed out 5 gallons of salt water for new salt water. I plan on changing out another 5 gallons Saturday.
Does anyone have any idea what could have contaminated my reserve water and do you think this plan on water changes will fix the problem? Should I change even more water. Many of my corals looked stressed right now.

saltyfilmfolks · Dec 18, 2018

Is the high tds directly from the rodi unit?
Or is it the water in the ato water container ?

700s are crazy high so I dunno what could have gotten in there

oldfishman · Dec 18, 2018

The high TDS are in the ATO water container. I even checked to be sure the plastic in the container was good for reef use. I did of course empty and scrub the ATO water container as of this morning the TDS is 0.

Frtdrmrose7 · Dec 18, 2018

oldfishman said:
The high TDS are in the ATO water container. I even checked to be sure the plastic in the container was good for reef use. I did of course empty and scrub the ATO water container as of this morning the TDS is 0.

Have you mixed saltwater in your container that receives the water from the RODI? If so you probably have salt residue in the container. This happened to me two months ago.