Interesting observation here. I have been using tropic marin pro reef in this tank and have been happy with it. About 400g of salt mix, including the initial filling, worth of tmp. The ORP is TMP is super low as other threads have discussed before, no one knows why, but the chemistry experts say it is probably just in the metal reduction states or along those lines. Not a big deal, but I have noticed the same thing, even running ozone with fresh TMP the ORP is under 200 and has been. I figured the tank looks good so who cares what is going on if it's the mix or my probes or what. The ORP generally keeps up a little each week if I don't do a WC.
Well anyway, trying to pinch pennies I decided since I have 150g of ESV left with the new "lithium issue free" component that Bob sent me I should use that rather than buying another bucket of TMP. How I do WC is I make up the water and then I pour a 5g bucket of the unheated mix into the overflow and then siphon out 5g before repeating. The temp drop this way is pretty minimal as I can wait between buckets and the sump easily holds an extra 5g for a few min so I don't worry about the ato kicking on or the gyre or return sucking air.
Interesting thing to me is that just changing 18g of water the ESV took the ORP from 240 to 310 overnight. I am just surprised a 15% WC had a 30% increase in ORP so fast when most freshly made water has a pretty low ORP. I don't know what this means if anything, and I don't think anyone else can tell what it might mean, but it is a very interesting observation to me. The WC was just water from the middle of the tank, no detritus or anything from the bottom.
I wonder how the mixes can be so very different. I wouldn't think there would be really much difference between top tier salts, but something in the tmp holds the ORP low for a long time, months at least, that isn't in other mixes.
