Few RO/DI Water and Buffer Questions

So ive already got an RO system set up that I was using for my salt tank before I took that down, now im setting up a 130g planted community with CO2 injection and I plan to dose NilocG Thrive as my general fertilizer for the plants......I want to use RO/DI since ive already got the system. Last time I did fresh water I was blindly following the advice of an LFS on using buffers in RO/DI water. I wanted to confirm that they were correct and that im remembering things correctly here....

All I need to do is use Seachem acid and alkaline buffers in a 1/2 ratio and add them to my RO/DI water and mix/aerate the water for at least 24hrs. This should set the Ph to ~7 and stabilize it there.....is this correct?

Do I need any GH or KH buffers/boosters?

 

You don't necessarily need buffers. It depends a lot on what you want.
And RO usually stabilizes itself at 6.8-7.2 when left standing open.

If you want a high tech planted tank, with high maintenance fertilizer regimen, soil plant substrate, CO2 injection and maybe shrimp, raising GH and KH is a good idea.

If you don't want shrimp or any hardwater fish (livebearers or rainbowfish), you will get away with only raising GH a little for the plants.

Technically GH and KH at zero are rarely a problem for the fish, only for plants and inverts.

 

I plan on having med-high light with CO2 injection and I am planning to use the NilocG Thrive fert (not sure if you consider that a high maintenance fert or not). Im not trying to grow super difficult plants but im sort of shooting for a middle of the road "can do most plats" kind of thing. Soil wise im still trying to make up my mind but was thinking about ADA aquasoil with a gravel cap.

I dont plan on having shrimp as its a community tank with angels that would probably just eat them.

That stuff being said, what would you recommend in regards to GH/KH?

 

I plan on having med-high light with CO2 injection and I am planning to use the NilocG Thrive fert (not sure if you consider that a high maintenance fert or not). Im not trying to grow super difficult plants but im sort of shooting for a middle of the road "can do most plats" kind of thing. Soil wise im still trying to make up my mind but was thinking about ADA aquasoil with a gravel cap.

I dont plan on having shrimp as its a community tank with angels that would probably just eat them.

That stuff being said, what would you recommend in regards to GH/KH?

No need to cap aquasoil with gravel, the gravel will work it's way down and you'll be left with a mix of both.

If you are using aquasoil, you do not want to dose any KH because you'll be fighting against the soil's buffering ability.

Instead dose GH only:

Target 25ppm of Ca using CaSO4.
Target 12.5ppm of Mg using MgSO4.

Use Rotala Butterfly | Planted Aquarium Nutrient Dosing Calculator to help you determine how much of each to dose into your water change water. Pre-mix these and ensure they are fully dissolved before you add the new water to the tank.

This is the easiest and cheapest way to remineralize RO water. It also adds the least amount of excess TDS.

 

No need to cap aquasoil with gravel, the gravel will work it's way down and you'll be left with a mix of both.

If you are using aquasoil, you do not want to dose any KH because you'll be fighting against the soil's buffering ability.

Instead dose GH only:

Target 25ppm of Ca using CaSO4.
Target 12.5ppm of Mg using MgSO4.

Use Rotala Butterfly | Planted Aquarium Nutrient Dosing Calculator to help you determine how much of each to dose into your water change water. Pre-mix these and ensure they are fully dissolved before you add the new water to the tank.

This is the easiest and cheapest way to remineralize RO water. It also adds the least amount of excess TDS.

Awesome, that made it pretty clear.....so just to confirm, use the Seachem acid and alkaline buffers AND the GH buffer or JUST the GH buffer?

 

Awesome, that made it pretty clear.....so just to confirm, use the Seachem acid and alkaline buffers AND the GH buffer or JUST the GH buffer?

Add nothing to the water except for CaSO4 and MgSO4. You can also front load your weekly amount of fertilizer into the water.

I personally add this to my RO water for use in a high tech, Aquasoil tank:

12.5ppm NO3 using KNO3 (fertilizer) - My soil has stopped leaching ammonia so I will need to tart adding more NO3 in the near future.
10ppm PO4 using KH2PO4 (fertilizer)
25ppm K using KNO3 / KH2PO4 / K2SO4 (fertilizer)

25ppm Ca using CaSO4 (GH remineralizer)
12.5ppm Mg using MgSO4 (GH remineralizer)

I add no buffers and no KH at all. I let the Aquasoil buffer my water.

 

Add nothing to the water except for CaSO4 and MgSO4. You can also front load your weekly amount of fertilizer into the water.

I personally add this to my RO water for use in a high tech, Aquasoil tank:

12.5ppm NO3 using KNO3 (fertilizer) - My soil has stopped leaching ammonia so I will need to tart adding more NO3 in the near future.
10ppm PO4 using KH2PO4 (fertilizer)
25ppm K using KNO3 / KH2PO4 / K2SO4 (fertilizer)

25ppm Ca using CaSO4 (GH remineralizer)
12.5ppm Mg using MgSO4 (GH remineralizer)

I add no buffers and no KH at all. I let the Aquasoil buffer my water.

Awesome thank you!

Side question: Does aquasoil ever stop buffering the water?

 

Awesome thank you!

Side question: Does aquasoil ever stop buffering the water?

It depends on how much KH is in the source water.

With 0 KH it will last years and years and will physically break down into muck before it stops buffering.

If you are using hard tapwater with a higher KH, it will exhaust it's buffering ability quicker, less than a year if the water is very hard + large water changes.

If you are using hard water, you will induce pH swings as the new water loses KH to the soil only to be bumped right back up during the next water change.

 

It depends on how much KH is in the source water.

With 0 KH it will last years and years and will physically break down into muck before it stops buffering.

If you are using hard tapwater with a higher KH, it will exhaust it's buffering ability quicker, less than a year if the water is very hard + large water changes.

If you are using hard water, you will induce pH swings as the new water loses KH to the soil only to be bumped right back up during the next water change.

I'll be using RO/DI so any hardness in it will just be what I reintroduce.

 

I'll be using RO/DI so any hardness in it will just be what I reintroduce.

If you GH boost with CaSO4 and MgSO4 only you won't be adding any hardness back.

 

If you GH boost with CaSO4 and MgSO4 only you won't be adding any hardness back.

Final question, if I'm setting up a bare bottom quarantine tank and want the water to match the display. Since the aqua soil won't be present to buffer the water should I add acid/alkaline Buffers or Kh buffers?

 

Since the aqua soil won't be present to buffer the water should I add acid/alkaline Buffers or Kh buffers?

No. Soil buffers in a lower pH-range than that stuff. Instead peat and/or botanicals (IALs, alder cones) should work. Alle these additives are designed to ultimately bring you to a neutral point. For a quarantine an acidic environment with tannins is very beneficial and reduces pathogen density.