Can I use my tap? Or should I use RODI?

[Freshwater_Lloyd]

So I’m trying to decide what my water source will be, I’ve kind of been in and out of the hobby for a few years now and recently decided I want to set up a planted 10gal nano tank and stock it with some Pygmy Cory’s, maybe some white cloud minnows or neon tetras? (I haven’t made up my mind yet) I have a 40gal breeder with an African Clawed Frog I rescued that does just fine with my tap water, and currently my 10gal is only stocked with 4 nerite snails. 
 

Right out of the tap my PH is 8-8.2, my KH is 13°, and GH is 20°. 
 

Obviously I don’t want to harm any fish or have them living uncomfortably. So my question is should I get an RODI system and remineralize and/or mix with de-chlorinated tap to lower ph/kh/gh? Thanks you to anyone who has some thoughts!

[Guppysnail]

My Pygmy cory do fine average 7.6-occasionally 8. Very hard water.  They spawn and seem active and happy. When it hits 8 I will see them flash occasionally.  I would just a bit of rodi I would not go the bother of full rodi. More pita than it may be worth. I hope that helps. 

[Freshwater_Lloyd]

On 7/7/2022 at 10:19 AM, Guppysnail said:

My Pygmy cory do fine average 7.6-occasionally 8. Very hard water.  They spawn and seem active and happy. When it hits 8 I will see them flash occasionally.  I would just a bit of rodi I would not go the bother of full rodi. More pita than it may be worth. I hope that helps. 

Thank you! Part of me wants to just get a $100-$150ish system and install it in my laundry room so I don’t have to mess with jugs at the lfs or grocery. I figured I’d have to at least dilute with RO because my water is super hard.

[Wrencher_Scott]

On 7/7/2022 at 7:27 AM, Freshwater_Lloyd said:

Thank you! Part of me wants to just get a $100-$150ish system and install it in my laundry room so I don’t have to mess with jugs at the lfs or grocery. I figured I’d have to at least dilute with RO because my water is super hard.

With that water I would just get a small RO system for evaporation top off. That's what I do. It just keeps the water from getting harder by evaporation. I don't do it so much because of hardness but because of bacteria. Bad bacteria like hardness and I have Discus and they don't do well in dirty water. 

With my RO system it would take days to do a water change, and there is no way I'm going to haul water around for no reason. 

If my math is correct your GH is about 358ppm, I would not sweat it one bit. Now if it was very low like 50ppm then you would need hardness. 

There are studies of fish being subject to lots of harness, like 2000ppm hardness with no ill effects. Heck lots of people put aquarium salt in their water all the time (not sure why), and some do lots of salt to kill parasites (salt baths) and it doesn't harm fish. I don't know what the hardness is in a salt bath off hand but I bet its very high. 

Anyway, again, I would not sweat it.

 

[nabokovfan87]

On 7/7/2022 at 6:56 AM, Freshwater_Lloyd said:

So my question is should I get an RODI system and remineralize and/or mix with de-chlorinated tap to lower ph/kh/gh? Thanks you to anyone who has some thoughts!

I will say, I don't think you have enough information right now to decide!

A.  Take a sample from the tap and measure PH, KH, GH, Ammonia, Nitrites, Nitrates.
B.  Aerate the same sample with an airstone for 24 hours, retest.
C.  Compare these results to your tank and determine what the difference is between B and C.  This is going to be the swings you're working with when you change water.

On 7/7/2022 at 10:18 AM, Wrencher_Scott said:

With that water I would just get a small RO system for evaporation top off. That's what I do. It just keeps the water from getting harder by evaporation. I don't do it so much because of hardness but because of bacteria. Bad bacteria like hardness and I have Discus and they don't do well in dirty water. 

I like this idea. Good point!

On 7/7/2022 at 6:56 AM, Freshwater_Lloyd said:

Obviously I don’t want to harm any fish or have them living uncomfortably. So my question is should I get an RODI system and remineralize and/or mix with de-chlorinated tap to lower ph/kh/gh?

Do you have a method to precondition water ahead of time?  A storage container for tank water you can use to mix RODI with your tap water?