RO/DI for Freshwater?
 

Is it OK to use RO/DI water for my FW tanks? I thought I read somewhere that it wasn't a good idea.

i do for my angels..they don't seem to mind. I have some blackwater additive stuff I add for fun..don't know if it really does anything.

Using RO will help keep the algae growth down.

I know of people doing it for thier DIscus too. its better for them...

less stressful/..

I use RO-DI for my discus...they seem to be thriving so...seems like a good idea to me!

For some fish and plants RO is recommended (such as some cichlids and discus) but for most fish I think dechlorinated tapwater is fine. RO/DI water tends to be pretty unstable. Just like you have to be really careful picking corals and fish that like similiar temps, and parameters, FW plants and fish require careful consideration re: temp. water hardness and ph.

for fresh water rays it's needed

Just curious, what do you mean by 'unstable'?

Angels (And most other south american fish) prefer soft water and the blackwater extract does the same thing as adding peat or a new peice of mopani bog wood. :)

one thing to note, if you use RO water and nothing else like was mentioned it is unstable.. PH will be all over as there is nothing to buffer it alk will be nuts... not recommended in any book. what is recommended is that if you use RO, then you must use a re-mineralizer or something like that.. ie black water extract, discus buffer ect.. this will re buffer the water to proper levels as you won't have anything left in the water to buffer it.

Steve

Ditto - remineralized is the way to go. What will happen over a period of time is that not only will the hardness/alk be all over the place, but the ionic balance of the water will become too dilute, actually causing osmotic shock to your animals... to use it once in a while for a 10% water change is fine for reducing nutrient levels and algae control, but prolonged use will eventually make your water uninhabitable... I did this once and wiped out a tank... sometimes we have to learn the hard way... *SIGH*
:redface:

yea that sounds about right. I used to use peat, then thought I'd give this a try..still thinkin I should get a log of driftwood

Just wanted to say the contributions to this thread were helpful. I learned something too.

Remember don't confuse alkalinity with hardness. Measuring alkalinity can be a method for inferring hardness but they are not one in the same. Alkalinity is a measure of pOH (inverse of acidity). Water that has a high carbonate hardness (KH) tends to have a ph greater than 7 and good buffering capacity; as in it is considered alkaline not acidic. Pure/RO water has no carbonate hardness and thus no buffering capacity so pH can swing uncontrollably (both up and down).

Like Steve said even soft water fish like discus and South American cichlids will require some reminerilization to their water if RO is used. FYI the water in the GVRD is already quite soft and a little acidic; RO is probably overkill but if you already have access to it...

If your water source is hard then RO/DI will be the only reliable way to soften your water. Peat and acid products are quickly consumed by the carbonates and will leave a bunch of neutralized compounds in the water.

R/O water is great for fishes that require soft water / low TDS, etc. In the future I plan on establishing a South American dwarf cichlid breeding project and will be using R/O water. Ensure that you add some crushed coral to the filter to avoid any pH crashes. The blackwater extracts that are on the market are a decent additive, plus you can use peat purchased from your local hardware store, i.e., Home Depot, Kent, Canadian Tire. This peat is SUPER cheap compared to anything purchased in a LFS.

J

PS: Forgot to mention that I'm in the market for a reasonably priced R/O unit myself.