A TDS experiment in increasing hardness of RO
After spending the past decade raising fish and shrimp in super-hard alkaline water (and choosing all my critters based on these water parameters) i have moved to a city where the water quality is so poor i'm forced to use 100% RO in all my tanks. So for the first time my problem is not how to lower the hardness but how to increase it. This is a particularly demanding issue in my shrimp tanks, as their little exoskeletons do not appreciate soft, calcium-poor water.
Currently i have bags of calcium carbonate in the tanks, which brings the hardness up to about 50uS; from there, i'm using Kent's R/O Right to reconstitute my water. A fellow fish geek suggested to me that, as saltwater is basically a super-concentrated version of freshwater (or conversely, freshwater is a super-dilute version of saltwater), i could probably use Instant Ocean or reef salt to accomplish the same thing as R/O Right (plus save money, as i'd have to use far less of it).
This makes perfect sense to me, and upon reading the ingredients to both R/O Right and several reef salt packages, i think it will work. My plan is to start with reef salts in the planted fish tanks and maybe the cherry/minami shrimp tank, and then switch all tanks if successful. I monitor pH and TDS with Hanna ep meters, and check KH about once a week with Mardel 5-in-1 strips. Next week i'll begin using reef salts to reconstitute water changes; today i'm still on R/O Right.
Today's readings (lower than the desired 150uS):
TDS: 108uS (about 85ppm)
Please let me know what you think of this plan.