Today, I was walking on the beach and found several nice rocks I thought I could add to my tank. I was just wondering, if I boil the salt and other nutrients from the rocks will they be safe for my freshwater tank?
No. You'll never be able to get all the salt out, and it will slowly leech out over time. As they've come in from the sea, you also can't guarantee that there aren't other pollutants in it.
I added 3 large rocks from the sea to my 50L tank, i put them in a bucket and soaked them over night amd there great! As long as you soak them a little salt with do nothing but good (what i got told) because tropical fish can be exposed to some salt.
Do NOT boil rocks. Adding hot water to them is fine and soaking them in it will be okay. As stated some salt is fine as long as the fish you have can tolerate brackish water. Boiling rocks is a an extreme hazard as they may explode.