Ro/di Water For Freshwater Fish? Or Just Ro?

[Ehaze]

My tap water is around 300-350 TDS, After the RO it is 12TDS, after the DI it is at 0.

I use only RO/DI for my reeftank, but would like to know if I can just use RO, and skip the DI?

any ideas?

 

[Ian H]

what fish are you keeping? I would imagine they would be fine with tap water that is de-chlorinated as thats what 99.9% of members on here use. Unles of course you are keeping a certain species?

 

[yvez9]

is something wrong with your tap water?
anyhow, RO should be fine unless you ahve lead or something in your water... You'd probably even need to add some sort of buffer to that water as pure water is not enough for fish.

 

[Ehaze]

I will just use RO, then, thanks.

the tapwater tds is at a normal level.

 

[yvez9]

i'm not sure what tds is
is there a reason you're not using straight tap water with water conditionner? ro water will most likely lack minerals required to keep fish healthy

 

[Ian H]

agree with the above if the tds is average the just go with that and use de-chlorinator, its what almost everyone uses unles keeping discus or using RO for a certain reason.

 

[Ehaze]

I will use tap then, I use the RO/DI unit for my reeftank, so I just figured it could not hurt the freshwater fish. but now I know.

Thanks!

 

[Ian H]

Im still learning but is the reason you use RO in a SW tank to avoid algae issues? they are alot different in a FW tank

 

[Ehaze]

I use the RO/DI wate in a reef tank, because it takes all the phosphates / any heavy metals / chlorine / nitrates out of the water, basicly pure clean water, corals can't take any heavy metals, chlorine, nitrates or phosphates.

Heavy metals, as you prob know copper pipe is what delivers the water to the hose, then into the tank, and copper is VERY toxic for any SW coral or invert, and will kill them fast.

Chlorine, burns most anything.

Nitrates, corals can't tank nitrates 20PPM + for more then a few weeks, then you will have die off, SPS need 0 - 5ppm or may dicolore or bleach. nitrates also feed algae and many kinds of bacteria.

Phosphates, cause some corals to brown out and loose color, also feeds algae and many kinds of bacteria.

the DI take care of any metals that get by the RO.

AND you will spend more money on dechlorinator in the long run, so why not fork out 180$ for a really nice RO/DI unit?

 

[yvez9]

the reason you can use RO water in a reef tank is because you add an ocean mix to it that will provide for all minerals required for the living creatures.
in a freshwater tank, you usually don't add anything therefore hurting your fish if no minerals are present.

dechlorinator costs me 50 bucks a year and i have 4 tanks. it would take years to cover the expense of RO unit + the filter that removes all minerals

 

[OldMan47]

You are spending way too much on dechlorinator Yves. Get a nice big bottle of Prime and only use 1 ml per 10 gallons of water like it says in the instructions.
The RO can be useful in freshwater if you have very hard water to reduce the TDS to a value that matches your fish. I have tap water that is well over 200 ppm of TDS and find that my fish do fine with straight tap water. When I am trying to breed soft water fish, I do reduce the TDS by mixing in some RO with the tap water to get the desired mineral content. Pure RO is too low in TDS for almost any freshwater fish so the added bit of reduction from DI is definitely not needed.