Assistance With Buffering Ro Water

  • #1
Good Day all,

Looking for a bit of assistance as I dial in my water to be used during water changes.

My tap water isn't that great due to high GH, KH, and TDS's so I would much rather start with a pure RO base and add in my GH, KH and keep a lower TDS overall.

My question to start is am I on the right track doing so? and if yes please critique my method I plan to use when staging my water to be returned to the tank.

First the details :

TAP Water -- I would rather not use straight as is (but can mix with RO if recommended) :
Ammonia : 0
Nitrite : 0
Nitrate : 0
PH : 8
GH : 180
KH : 240
TDS : 720

RO Water -- Base with no additions
Ammonia : 0
Nitrite : 0
Nitrate : 0
PH : 6.5
GH : 15
KH : 20
TDS : 28

Current tank water -- (Lowering some values last few weeks with RO water changes and no buffering)
Ammonia : 0.5
Nitrite : 0
Nitrate : 50-60 (down from 80ish) (Goal : 20)
PH : 8 (Goal : 7.5 - 8)
GH : 160 (down from 180) (Goal : 120)
KH : 90 (down from 240... would like to keep it here) (Goal : 120)
TDS : 630 (down from over 850) (Goal : 400 or so?)

Sooo, what I've been doing is straight RO to lower the GH, KH, and TDS. Now that my KH is getting where I want it around 6 degrees (little low at the moment now), I would like to start buffering the KH so it does not go any lower and cause PH instability.

My plan is to use seachem alkaline and acid buffer to keep KH where it is or a bit higher and conitnue to lower GH if possible while also lowering TDS further.

I also have Equillibrium to add GH back in so I have "GOOD" minerals for my plants in addition to adding CO2 to the mix this week.

Any tips, or pointers you have would be greatly appreciated!

Once again, i'm hopeful to have a solid base, minimal fluxuations in my water quality and build off the RO to stage it correctly before adding back to the tank. Problem with adding tap water in to do so will jump the TDS, KH, and GH way up in addition to chlorine etc etc and seems like a messy way to get there and correct it all.

  • #2
You’re on the right track. Just mix it and add the buffers to get it where you want it before doing a water change.

My KH in my Ram tank are around 40, and I have no PH swings. I think you’re totally fine there.

  • Thread Starter
  • #3
One more question I forgot to ask, if my TAP and TANK have a GH of 180ppm (approx 10 dGH) is it safe to say that includes the GOOD nutrients plants would need (IE Calcium, Magnesium, and Iron)?

I'm questioning when I prepare my RO water if I should add in some Equilibrium to add those 3 nutrients but i'm still in the water change cycle to 'lower' the GH not raise it. Which comes to another question, if I add Equilibrium to approx 6 dGH (100 ppm) i'm assuming that will not raise the current GH of 180 that I have now, overall effect would just be less of a jump in lowering my current value. please correct me if I'm wrong.

  • Thread Starter
  • #4
Looks like I found the answer to the bulk of my GH questions here :

In my case, Yes, I should be using GH suppliment like Equilibrium and not assuming a high GH = good nutrients. I wll buff my GH to 120 ppm where I want it and evaluate how that equals out over the next number of water tests, this way I know I will have the nutrients my tank needs and is currently lacking for sure.
Inactive User
  • #5
One more question I forgot to ask, if my TAP and TANK have a of 180ppm (approx 10 dGH) is it safe to say that includes the GOOD nutrients plants would need (IE , , and )?

As you likely found out, GH in water is mostly comprised of calcium and magnesium. Se Chem Equilibrium is a mix of various sulfate salts, but primarily (95%) calcium sulfate and magnesium sulfate. Many shrimp aquarists simply use epsom salts (magnesium sulfate heptahydrate MgSO4.7H2O) and calcium sulfate exclusively to make their own DIY GH booster.

GH reading in itself won't determine whether you have all necessary nutrients, as it doesn't account for nitrate, phosphate, potassium, etc.

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