Dosing RO water for kH & pH

[SilverB]

Hi All

I wonder if you can help me - I'm struggling to completely grasp this subject, so I'm hoping you can give me some perspectives.

First things first - I'm planning to keep some Chili Rasboras (6) in my 21 litre (5 gallon) nano tank (I've ordered some Hardscape materials to play with and I'm very excited)

Now, from my research, these fish like the below water parameters:
pH: 4.0 - 7.0 (acidic prefered)
KH: 3 - 12 dkh
GH: 1-2

I'm going to be using RO water and originally was planning to use Salty Shrimp gH/kH, but then I heard that it makes some fish species poorly - I think due to sodium levels

So then, I was looking into Seachem Replenish (favouring over Equilibrium, because I'm anxious to make the fish happy), then realised it would only help me raise my GH (which I will to reach 1) but not impact my KH or pH.

Now, I know the RO water is pure and therefore will be pH 7.0, BUT (and this is where I'd like to confirm my understanding) this pH will be unstable unless I raise kH from 0.

So, this is where I'm struggling - I've been looking at Seachem Acid Buffer and Seachem Alkaline Buffer. I was hoping to be able to make the water more acidic as this is the species' preference, but I'm unsure about how to do this given the adjustment of Kh will impact the pH: I found this below - and I'm assuming I'd need to aim at 6.5 pH and use both Acid and Alkaline buffers?

I'd prefer to use an off the shelf product rather than do some mad scientist calculations (maths is not my strongest suit) but any advice you can offer would be really appreciated.

Also - How much in advance can I remineralise RO water before using it in my tank - is it okay if it sits for a few days/a week? The tank is small so I figured I could mix a big batch and use as and when needed.

 

[StevenF]

While I have never had these fish is important to understand their native enviromante. They live in small streamsand ponds in southeast asia. The was is basically rain water with some organics and few minerals.

So it is best is you lightly fertilize the RO water and use a GH booster to maintain a GH of 1/to 3dGH. Ignore the KH requirement you read. You won't soft fresh streams or ponds water with KH much higher than the GH level. typically soft water will have GH and KH levels very close to each other. So in their natural enviromanent the water will have A GH or KH of 1-3 degrees. It could be all GH or all KH but most likely a mix of some GH and KH. Unfortunately with the materials you can buy a an aquarium shop you it is easiest to to aim for all GH with 0KH. And surprisingly is is seay to maintain a stable PH in RO water.

By a small decorative sea shell and put it in your filter. The shell is made of calcium carbonate. Calcium carbonate only dissolves in acidic water . But it does not dissolve in water with a PH above 7. My 5 gallon RO shrimp tank has a PH of 7 all the time thanks to the sea shell in the filter. A single shell is last a year or more before it dissolves away. At my local pet store I purchase a small bag of sea shells for about for a few dollars. That bag will likely last me about 7 years.

To the best of my knowledge there are no GH boosters on the market that contain sodium. Most have potassium. But so do fertilizers and many people US KH booster that have,,,, more potassium. Most aquariums have more than enough potassium. just from the fertilizers. And GH test kits don't even detect potassium.

Many people use salty shrimp so I would have no concern with you using it. One concern I have is that in nature streams always have some sodium and potassium. And animals need potassium and sodium to live. Having no sodium and too much potassium might be lethal to them. I personally add a 1/64tsp (about 120 milligrams)Sea Salt after a water change to insure I have some sodium in the water. And since it is sea Salt it will have very small quantities of other elements and addition to sodium that animals need. I don't know if it is helping my shrimp but it is definitely not hurting.

can I remineralise RO water before using it in my tank - is it okay if it sits for a few days/a week? The tank is small so I figured I could mix a big batch and use as and when needed.

You can do that but one word of caution. Use all the water and then discard the any excess after your water change.
after a water change don't add more RO and GH booster to the excess water already in the pucket.

The reason is that RO systems don't do well at removing Boron. and I suspect Boron levels in my bucket had gotten very high. in my tank and kill my first batch of shrimp. After discarding the water in the bucket and a large water change in the tank ordered more shrimp then they didn't die.

And for my last bit of advice is if possible use a 10 gallon or larger tank. IN a 5 gallon you would be limited to about 5 or 6 fish. Chili Rasboras are schooling fish 5 fish a ia 5 gallon are more likely to hide because they are not comfortable in such small numbers. The are ore comfortable in larger numbers and more likely to show good schooling behavior in a group of 10 or more.

 

[seangee]

First things first - I'm planning to keep some Chili Rasboras (6) in my 21 litre (5 gallon) nano tank (I've ordered some Hardscape materials to play with and I'm very excited)

Now, from my research, these fish like the below water parameters:
pH: 4.0 - 7.0 (acidic prefered)
KH: 3 - 12 dkh
GH: 1-2

I'm going to be using RO water and originally was planning to use Salty Shrimp gH/kH, but then I heard that it makes some fish species poorly - I think due to sodium levels

I keep these in RO water. No need to add minerals. I have a lot of wood and plants in the tank so the pH is fairly low (around 5) but remains stable. Make sure you do regular water changes and they will be fine.

 

[itiwhetu]

Just use drift wood and maybe peat to keep your water acidic and soft. Do water changes weekly ( 25% ) . The tannins will burn off with time and you will have an acidic soft tank perfect for these guys. By the way these guys aren't that fussy.

 

[seangee]

Just use drift wood and maybe peat to keep your water acidic and soft. Do water changes weekly ( 25% ) . The tannins will burn off with time and you will have an acidic soft tank perfect for these guys. By the way these guys aren't that fussy.

OP lives in London. Neither drift wood nor peat will soften that water.