Loaches Online Forum

can i use rain water to change water for my clown loach tank? i tested rain water tds at 3ppm. ro water .1ppm, tap water 220ppm. i been using ro water for a year now and my fish is happy in it. i have put 7 of 50 gallons trashcan outside to collect rain water. im trying to save money on ro water. anyone use rain water? is it safe for fish?

If the rain water is safe at all, then it is safe for Clown Loaches.
If it is collected off a clean roof. A new roof may still be giving off some of the materials it is made of. (I still get a little gravel off mine after 15 years).
If there is any copper in the system the water is probably not good. (Some places have copper trim, gutters or other parts.)
If you are directly downwind of a factory or other place that creates a questionable discharge into the air you might need to be careful of which way the wind is blowing before collecting.

I generally allow the first storm of the season to wash off the roof, then start collecting.
If the water in the tank has higher GH, KH or TDS then go slow with the rain water, or else add some minerals (seachem equilibrium for GH and baking soda for KH). But since you say you are using RO, then whatever minerals you add for the RO would work just fine.

i dont collect my water from the roof. i leave my trashcan out in the open and in the middle of my backyard. rain all day yesterday and all my trashcans are full. i will change my water only 50 gallons to see if theyre ok

Wow! That's some rainfall