The Puffer Forum

I know, I'll get the ion and HPLC chromatographs running in my lab and see what I can find in my tap and tankwater

Actually, I'm half serious

I still don't understand why someone would use RO water in a heavily planted tank..

I haven't had time to read all 4 pages, but I'll comment on a handful of things.

1. Keep in mind when talking about planted tanks.. there are some people out there that value the plants in the tank more than the fish in the tank. So what they are doing may be best for the plants, but not for the fish. That is the case in many "extreme" planted tanks, so keep that in mind.

2. RO filters and waste.. RO filters are bad if you are on a well, because they require a lot of pressure to basically push the water through the cannisters and filter out a tiny bit of "pure" water. So it isn't great for your well pump. And yes, there is a ton of waste water. For example, I used to run an RO filter at my last apartment where the water was horrible. With new, clean filters, I could start that sucker up on full blast from the kitchen sink.. and 10 hours later I'd have filtered out a full 5 gallon bucket of "pure RO" water. So that's 10 hours of water running down the drain, and trust me, it wastes a lot more than it produces! I probably didn't have the most efficient system, I bought it second hand, but still.

3. Why use RO in planted tanks? Well, if your tap water is just dang horrible and will kill your fish, you don't have many other options. I've had to do this in the past when I had sick or delicate species.

4. Rainwater -> pH crash? That's just silly.. No rainfall will drop the pH that far to completely crash things. Even if it was a flash flood, the minerals in the floor of the lake or river substrate would help buffer, along with the water that is already there. And remember that nearly every water source in nature has another, main source, that is constantly replenishing it (underground springs, streams, etc). Maybe extreme climate's might have some issue with it, but there probably wouldn't be many fish surviving in those situations one way or the other.

Do I do weekly water changes in a heavily planted tank? Sure do, as large as I can! But my planted tanks also have fish in them, and I'm doing the water changes for the fish, not the plants. If I just had a planted tank and was trying to win some awards with it, I might do things differently, but if I'm looking for a healthy ecosystem, then I'm going to do water changes. Why? Because, as I said above, nature is CONSTANTLY doing water changes. Water just doesn't appear and hover in a spot and magically filter clean because of a few plants, clean water is brought there by feeder streams, underground springs and aquifers, etc. Rain supplements it of course, but its not the sole source.