ro/di water

[agentgreen]

hello

starting a thread on this cuz i cant seem to find much info when i search..

i am in plans to startup a saltwater tank, and one of my first purchases will be a ro/di filtration unit....is it safe to use this water in my freshwater tank? after i slowly acclimate my fish to it of course...

thanks!

 

[TankGirl]

You can use it, just mix it with tap. Any particular reason you want to use it on your FW tank? One of the reasons FW is cheaper to run than SW is the ability to use plain ole tap water, but sometimes tap water is of poor quality and it makes sense to dilute with R/O.

 

[agentgreen]

well i figured since it was highly filtered water, and i was going to use it with saltwater setup, might as well use it for fresh....any reason for diluting it? does tap water contain chemicals/minerals/something beneficial to freshwater setups that the ro/di process would remove?

 

[Medusa Head]

The idea behind RO/DI water is to completely "tear down" your water so you have only H2O, absolutely nothing else whatsoever in it. Then you buy high grade aquarium products (gh minerals, trace elements, kh buffers) to "reconstitute" it to whatever kind of tank you're keeping.

I have no experience with saltwater. But for example if you are going to have a fw discus tank, you would want a pH below 7 (low kH) and soft water (low gH), whereas if you are keeping African Cichlids you would want a pH above 7 (higher kH) and harder water (higher gH).

Many people will tell you to you can use products like baking soda, epsom salts, etc., however I prefer to buy the aquarium stuff as I don't mind paying a little bit more for what I believe to be a higher grade product. For kH, I use Seachem Alkalkine buffer. For gH, I used to use Seachem Equilibrium, however, I don't like that it has such a high potassium content (I dose potassium seperately), so I switched to Kent Botanica gH+ to raise gH as it contains only calcium and magnesium which is pretty much what you're talking about when it comes to gH. And finally for trace elements, I use Seachem Fresh Trace.

 

[TankGirl]

Excellent breakdown of the process, Medusa Head.

This illustrates why you will often hear the advice to keep fish that are adapted to your tap water, since it takes some work and $$ to manipulate your tap water or use R/O. But tap water varies so it really pays to test it right out of the tap, after it has sat out overnight, and see what your tap water profile is. Many people mix tap with R/O to provide the trace elements that the fish require.