Rainwater and electrolytes

[Michael Welber]

Someone has suggested to me that since I use rainwater from my cistern in the fish tank that I may be having a problem with the electrolytes in the water. It's possible since a number of fish have died from reasons unknown. I have two questions:

1. How does one test for electrolytes in the water?

2. If this is so, how do I add electrolytes to the water? 

Any ideas on this? Thanks. 

[Jimi Subgum]

1. electrolytes can be tested with a blood test. conductivity of the water. Ca, Na, Mg, K, HCO3 are all electrolytes.

I'd bet most electrolytes are being added with the fish food.

electrolytes are needed for cell function in fish and people.

I highly doubt your fish kills are related to a lack of electrolytes.

2. add Ca, Mg, K, HCO3 to the water.  NaCl can be added, just watch the dose or it will effect your plants.(check other posts)

[Michael Welber]

That's my feeling too. Thanks. I've added salt (pool salt) before and perhaps I will again.

[TCLynx]

What is your pH?  If you are using rain water then it is also possible your system needs some extra calcium carbonate and potassium bicarbonate regularly.  And much of the rest can be taken care of with a bit of seaweed extract.