Getting the RO water params right for CRS

[Lphien]

Hello everyone,

I’m planning to setup a new 23L planted tank with CRS. I’m planning to use ADA Amazonia 2, pressurized CO2 and strong lighting. My tap water parameter here in Paris, France from what I found online is around:

• pH: 7.5
• KH: 8
• GH: 12

I have access to RO water. I want to ask if it is possible to dilute my tap water with RO water to get the right parameters for CRS (PH under 7, KH: 0-2, GH: 4-6), if yes, what should be the proportions, or I’m better off remineralize my RO with some GH+ or GH/KH+. Also I have read that it is difficult to keep CRS with high tech setup, because of CO2 and fertilizers, my priority is the plants and overall look of the tank, not breeding CRS. What are your opinions on this ?

 

[LMuhlen]

Just going with the numbers you provided, since you apparently have 50% more GH than KH, at the limit of the KH range that you gave, 2dKH, you would have 3dGH, below the minimum. Considering only this, it looks like you'll have to remineralize to boost the GH a bit, so all things considered, maybe it is safer to just use RO water and remineralize all the way. If you aim for the center of the KH range you provided, you would need to use 7 parts of RO water to 1 part of tap water, so it's not like you are saving much water either...

But since you are planning on getting some expensive high tech gear for that tank, you might as well buy a KH and a GH test kits and feel safer about your choice...

 

[MichaelJ]

Hello everyone,

I’m planning to setup a new 23L planted tank with CRS. I’m planning to use ADA Amazonia 2, pressurized CO2 and strong lighting. My tap water parameter here in Paris, France from what I found online is around:

• pH: 7.5
• KH: 8
• GH: 12

I have access to RO water. I want to ask if it is possible to dilute my tap water with RO water to get the right parameters for CRS (PH under 7, KH: 0-2, GH: 4-6), if yes, what should be the proportions, or I’m better off remineralize my RO with some GH+ or GH/KH+. Also I have read that it is difficult to keep CRS with high tech setup, because of CO2 and fertilizers, my priority is the plants and overall look of the tank, not breeding CRS. What are your opinions on this ?

Given the small body of water I would just go 100% RO and remineralize from there. If you aim at 4-6 dGH you will be fine. And your plants will be fine in the 1-2 KH range and make it easy for you to adjust acidity with botanicals such as Almond Leaves. You can keep Crystal/Bee and other shrimps with CO2 injection just don't aim that high and keep it stable, 10-15 ppm is fine to be safe. Research is scant but at least according to one study The mortality rate appears to climb steeply when you reach the +30 ppm range. But I bet how well the stock is adapted plays a role as well.

Cheers,
Michael