Something strange going on. Extremely high TDS in rock "curing" water

[cvrle1]

I am stumped, and can use your help with this one. I have extremely high TDS from water that is sitting in the rock bucket. High as in 880 ppm

I calibrated my Milwaukee TDS meter with proper calibrating solution to 800ppm
Tap water, I have TDS reading of 12-18 ppm (Inline TDS meter on the RODI is showing 12, Milwaukee TDS meter is showing 18)
Clean water coming out of RODI is showing 0 on inline and 2 on Milwaukee (milwaykee has +- 10ppm accuracy, so this is fine I think)

I filled up bucket with dead rock that I bleached several months ago (using bleach and tap water) with RODI water and let it be for 2 or so weeks (no salt or anything else, just RODI water). I have powerheads in there to move water around. I just took a sample to get TDS reading and got 880ppm with Milwaukee ops:

For rock, I bleached it all (about 120#) in bleach and water solution for a week, let it dry out in the sun for a week and then put it back into the bucket. I washed bucket out with hose and dried it out as well before I put rock back in. Rock was sitting dry in that same bucket for 3-4 months. Before I filled it up with RODI water there was no bleach smell.

Could bleach residue somewhere cause readings this whack? Something else? No idea what happened and why I have way worse TDS reading than tap water.
Thanks for the help

[cvrle1]

Looking into this more, and it looks like it is expected. Apparently adding rock, no matter how clean will add to the TDS reading. I just didnt expect it to be this bloody high. 880ppm... jeebus.

[Bblinks]

Thanks for sharing! I would've suggested to do a few water changes and see if it made a difference.

[cvrle1]

Yeah I thought something is wrong, but doing more digging around it is normal. Rocks will leach minerals, no matter what they are. Dead, live, doesnt matter. Apparently only time 0 TDS is important is on initial tank setup, water changes water and top up water.

I wouldnt have never guessed that had I not taken this reading today and almost got heart attack haha

Interesting read on post 21 and 23 here about this topic: http://www.reefcentral.com/forums/sh....php?t=2201617

[Bblinks]

lol Good luck with the new tank build, exciting times!