R/0 Water in a Fresh Water Tank

[NoSump]

This question is a bit off topic, but hopefully Ninong or other reefers will know the answer.

I purchased an R/O device in order to prepare water for my reef tank. I had planned to also use R/O water for replenishment and water changes of my fresh water tank (although the tank is very stable and healthy, I am assuming that a more pure water source might improve fresh water fish health and longevity).

As you know, an R/O removes many "good" minerals along with the bad metals, and chloramines, nitrates, etc. In a reef tank, the salt water mix, and other additiives return the "good" minerals back into to the purified water.

My question is, since in a freshwater tank we do not add minerals back into the water - is R/O purified water appropriate for a fresh water tank? Since fresh water is far less pure than ocean water, I am wondering if the switch to R/O water might actually be harmful.

[Ninong]

Pure water is not harmful. R.O. water is pure water. Rainwater would be pure except for the contamination it picks up in the atmosphere from manmade pollutants. Rainwater in some remote corner of the globe would be more pure than rainwater in a heavily industrialized region. The pH in rainwater in industrialized regions is often much lower than neutral (7.0 pH) because of this pollution, which is why it is called "acid rain."

Now, having said all that, what exactly are you keeping in your freshwater aquarium? Your fish may have a natural adaptation for water that is not pure and may even require "impure" water to thrive. Obviously fish from the Amazon river are adapted to lower pH levels than fish from the African rift lakes.

[NoSump]

Ninong:

Quote:
Now, having said all that, what exactly are you keeping in your freshwater aquarium?

Thank you, I have a mix of fresh water species (mostly indo-paciific/barbs, etc - no African fish). It's been running for many years.

If the R/O water does not represent a problem in a fresh water tank, will it provide any benefit? Are my assumptions about health and longevity accurate?

This may be a case of, "if it isn't broken don't fix it".

By the way, Ninong, have you ever tried the Berlin Method? Posiedon has piqued my curriousity about that approach.

[Ninong]

I haven't kept freshwater fish in more than 40 years but way back when I did keep them, I used tapwater that I let sit out overnight so that the chlorine would dissipate. That was before chloramine was used as a disinfectant in tapwater.

I believe they sell all sorts of additives to condition your water for specific species of freshwater fish now, especially Africans (higher pH) and Amazonians (acidic water). I'm really not up on all the latest freshy stuff but I'm sure discus and cichlids require entirely different habitats to thrive.

As far as the Berlin Method is concerned, probably 95% of the people who post to the various reefkeeping bulletin boards employ some modification of the Berlin Method. The original Berlin Method called for live rock and a protein skimmer, plus strong water movement and strong lighting. Notice that the original Berlin Method was bare bottom, no substrate. Over the years, many aquarists have added a sand bed to the Berlin Method. Then, more recently, refugia have been added. As long as you employ live rock and a protein skimmer, you can probably still say that you are running some version of the Berlin Method. If you are running without a skimmer, you probably shouldn't call it the Berlin Method. And if you are running an algal turf scrubber or a so-called "miracle" mud filter, you are not running Berlin.

It really doesn't matter anymore. There are several ways that work. The Berlin Method was radical at the time it was introduced but it is plain vanilla today. Cutting edge today would be setting up a VERY large system with two or three specialized attached refugia.

[NoSump]

As far as the Berlin Method is concerned, probably 95% of the people who post to the various reefkeeping bulletin boards employ some modification of the Berlin Method.

Ninong:

Thank you. I've noticed that virtually everyone on this site utilizes a sump.
I thought that the Berlin method did not require the use of sump (that it was simply live rock, dsb, and a skimmer)?

[Ninong]

Ninong:

Thank you. I've noticed that virtually everyone on this site utilizes a sump.
I thought that the Berlin method did not require the use of sump (that it was simply live rock, dsb, and a skimmer)?

If you have live rock and a protein skimmer, you can probably claim that you are running the Berlin Method.

Protein skimmers were developed in Germany and became popular with members of the Berlin reefkeeping community. They discovered in the late 1980's that if you had live rock and a protein skimmer, you didn't need a trickle filter or any other form of filtration. That was a departure from the most popular form of filtration at that time, the trickle filter.

Right about the same time, metal halide lamps became popular over there, too. It was several more years before protein skimmers and metal halide lighting became common in the U.S. Most aquarists over here were still running fluorescent lamps of some sort and trickle filters until the early to mid-'90's.

BTW, a deep sand bed was never a part of the Berlin Method. If you add a deep sand bed, you have a modified Berlin Method.