Osmotic Balance ?

[PhishPhreek]

So if you spend the money for an RO systerm to take all the minerals out, why should you put some minerals back in ?

[geoff_tropheus]

I am not sure RO takes all the minerals out.

I know that if you drink demineralized water, it will ruin your teeth.

The water has a very high affinity for "wanting" stuff, it wants minerals

[wesleydnunder]

A good RO system can give you better than 99% rejection... virtually distilled water. Housing fish in straight RO water will severely upset their homeostasis, causing the kidneys to have to work overtime and eventually fail while severely depleting electrolytes in your fish.

Putting minerals back in the water assists the fishes' osmoregulation by providing more ions on both sides of the semipermeable membrane; i.e., less water enters the fish and fewer electrolytes leave it.

Mark

[blacksmith37]

RO, DI, and distilled waters are very different to a chemist/engineer; and I think ,to a fish.
I think RO is silly for an aquarium; mostly because what is in it depends so much on the membrane and its condition.

[wesleydnunder]

RO, DI, and distilled waters are very different to a chemist/engineer; and I think ,to a fish.
I think RO is silly for an aquarium; mostly because what is in it depends so much on the membrane and its condition.

True.

In the better RO systems the product can get to as low as 2 to 3 ppm TDS. I worked at a hemodialysis clinic as chief tech back in the early 90s. Our RO/DI system was provided by a company called IONPURE. It was a 5,000 gpd system that had to deliver the purest water for the production of dialysate.

The membranes in that unit were uber expensive and had to be purged daily to maintain their performance.

Bob, the lowest natural TDS I've read of is in certain black water rivers in SA where the dicus come from. The lowest I've seen was 67 ppm TDS. Up here our TDS can get to 700 ppm.

Mark