Ro/di & Water Top Offs

I heard of people using RO/DI to top there tanks off. Just wondering if this is ok to do? If my tank PH is 7.8 and the PH of the DI is lower is that still ok?

 

Doesn’t make much sense. You’re adding water with no nutrients.

 

I think most of the time when you here of people using RO/DI water for aquariums they're using it for saltwater, since tap water usually doesn't work for saltwater.

For freshwater, adding RO/DI or distilled is pretty useless, unless you have something you're trying to filter out of your water. You'd have to buy products to remineralize your water, you'd have to re-acclimate your fish to a new PH, it wouldn't be worth it. Dechlorinators are much more efficient for freshwater.

 

I think most of the time when you here of people using RO/DI water for aquariums they're using it for saltwater, since tap water usually doesn't work for saltwater.

For freshwater, adding RO/DI or distilled is pretty useless, unless you have something you're trying to filter out of your water. You'd have to buy products to remineralize your water, you'd have to re-acclimate your fish to a new PH, it wouldn't be worth it. Dechlorinators are much more efficient for freshwater.

Oh got it. The people who I heard saying that probably had saltwater tanks. I have heard that if your water is really hard you can mix DI with tap though for freshwater.

 

I top off my shrimp tanks with RO/DI because I want the parameters to remain more consistent. When you add tap water you can inadvertently raise KH, GH, and TDS. Shrimp hate parameter fluctuations, so I do this as a precautionary measure.

Fish though? Screw it, I use tap water. Bettas and corys aren't going to be effected by a slight change in TDS like expensive shrimp, especially if you're doing your weekly water change to balance everything back out.

 

WE use RO/DI water inside Saltwater tanks primarily. However its not such a bad idea to use in freshwater systems between water changes and only for top offs.

This is my way of thinking. I do this for both saltwater and freshwater.

RO/DI PROS
Controlled water quality. No Silicates, Nitrates, or other issues at all with RO/DI water. Yes, you're not putting anything inside the tank nutrient wise but you are diluting the TDS level.
For a second, lets consider what happens with evaporation inside a tank. When water evaporates, only water evaporates. The evaporation process leaves behind the mineral content and solids of the water increasing the TDS of your water. There are also several other factors that increase as well. With the addition of RO/DI water you can bring your TDS back to normal, by diluting the ratio of solids to liquid.
Some fish do well with higher TDS (general statement, I know) like Shellies or Cichlids, others do not do well with high TDS like Jack Dempseys or Electric Blue Acaras.

Just a general suggestion take it or leave it. the important thing is to find what works best for you and your tanks, as I said this is just my way and how I manage all my 37 tanks.
Anthony

 

I think most of the time when you here of people using RO/DI water for aquariums they're using it for saltwater, since tap water usually doesn't work for saltwater.

For freshwater, adding RO/DI or distilled is pretty useless, unless you have something you're trying to filter out of your water. You'd have to buy products to remineralize your water, you'd have to re-acclimate your fish to a new PH, it wouldn't be worth it. Dechlorinators are much more efficient for freshwater.

well said.

 

I think RO for top offs makes perfect sense and if RO was cheap and came out of the tap I would do it too.
OP is just talking about top offs, not water changes. You don't have to remineralize top offs.
When water evaporates it leaves behind all minerals. So if pure water is leaving the tank, then only by adding pure water back can parameters stay constant. Otherwise, you keep adding tap minerals and water evaporates and then you add more minerals that never leave until an actual water change.
Of course, most fish don't mind either way.

 

I heard of people using RO/DI to top there tanks off. Just wondering if this is ok to do? If my tank PH is 7.8 and the PH of the DI is lower is that still ok?

Hello Fred...

The vast majority of fish you get at the local pet store will be fine in the vast majority of tap water. All you need to do is treat the water with a product that removes chlorine and chloramine and detoxifies forms of nitrogen. I use Seachem's "Safe", but there are others that will do the same job. Using Reverse Osmosis or Distilled water can get a bit expensive if you have multiple tanks and isn't necessary unless you keep a tank that doesn't require weekly water changes.

A pH of 6 to 8.5 is good enough for most fish, as long as you change out most of the water regularly to maintain a steady water pH.

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