Lowering pH with Seachem Acid Buffer

I’ll talk about how to lower ph using Seachem Acid Buffer and Alkaline Buffer. Other items are phosphate based, which is fertilizer for algae.


Preparing your equipment, you will need the following:
-Seachem Acid and Alkaline Buffer
-5 gallon bucket (40L approx) or mixing container
-pH tester, preferably an electronic one if possible
-water mixer, airstone or water pump

STEP 1: First, determine if you can use 100% tap water or not. If your KH is around 4 or less and GH is less than 10, you should be fine to use your tap water to mix/lower pH. Initial tap water pH is not as important because of the low KH. (Low KH = easy to adjust pH; High KH = hard to adjust pH)

If your tap water does not fit these requirements, you can mix R/O water and tap water to reach a mixture with a low KH. 

Tap Water:
pH = 8.0
GH = 11
KH = 15

2 gallons tap : 3 gallons R/O
pH = 7.13
KH = 4

So now that you have your tap:R/O mix ratio, you can add Acid Buffer to reach your desired pH, allowing time for pH to stabilize.

STEP 2: Desired pH = 6.0, starting pH = 7.8
Added 1/4 tsp Acid Buffer: pH = 7.3
Added 1/4 tsp Acid Buffer: pH = 7.3
Added 1/2 tsp Acid Buffer: pH = 5.5 STOP!
Total: 1 tsp Acid Buffer

Let the water mix. pH rebound to 6.9

STEP 3: simply repeat Step 2. Desired pH = 6.0, starting pH = 6.9
Added 1/4 tsp Acid Buffer: pH = 5.8
Rebounded to 6.5
Added 1/4 tsp Acid Buffer: pH CRASHED! drop in pH, pH = 4.3
Total: 1/2 tsp Acid Buffer

STEP 4: Slowly add Alkaline Buffer to bring pH back up to desired level. Be careful not to exceed the target, as you are essentially adding KH and all the previous steps would have been for nothing.
Added 1/8 tsp Alkaline Buffer: pH = 5.1
Added 1/8 tsp Alkaline Buffer: pH = 5.8 STOP!
Fine tune to reach desired pH level.
Total 1/4 tsp Alkaline Buffer

Conclusion: So after testing the water and playing around with the buffers, the following can be used to lower pH:

Starting pH = 7.8 —> Desired pH = 6.0
2 gallons tap water : 3 gallons R/O water
1.5 tsp Acid Buffer
1/4 tsp Alkaline Buffer

You can manipulate these numbers to calculate the total required for larger tank sizes. Also, keep in mind that substrate/hardscape plays a role in lowering/raising pH.