Emergency question (Freshwater)

[wds21921]

Since I've not done freshwater in 20 years I've got a question.

With the advent of RO/DI now, are electrolytes in freshwater a necessity? Without them present in the water would it have any detrimental effects on the fish?

I know it's a saltwater forum but I trust most of the opinions here and need a quick answer before I do a water change for a friends tank.

[Randy Holmes-Farley]

Yes, you'd likely want to add back a little salt when making the initial batch of water. For top off it is fine without additives.

[wds21921]

Thanks Randy, I'm looking at changing out about 30 gallons of water in a 55 gallon freshwater tank, how much salt would you recommend for 30 gallons of freshwater? Is reef type salt ok to use?

[Randy Holmes-Farley]

It depends a bit on the type of fish, and I'm not an expert. Reef salt is likely fine. There also are products just for this. I'd search some freshwater sites to see a recommended amount, but I'd guess on the order of a teaspoon per 10 gallons is good.
Here's Kent's product an amount recommendations. Seawater salt dose would be similar.

http://www.kentmarine.com/freshwater/conditioners/ro-right.htm