View Full Version : Lowering pH with Seachem Acid Buffer

26th Nov 2008, 01:23 PM
I will discuss how to lower pH using Seachem Acid Buffer and Alkaline Buffer. From my research, the Seachem Acid/Alkaline counterparts are the best buffers for adjusting pH and not creating an algae bloom. Most other products are phosphate based, which is fertilizer for algae. Any other acid/alkaline buffer products may be use, but be wary of their effects on your plants/fish/shrimp.

(This process was developed by Marc Wong, http://www.ventralfins.com, and adjusted to fit my particular water conditions and desired pH for keeping Betta Macrostoma at pH = 5.5 - 6.5; No, I do not feed my shrimp to my bettas)


Prepping equipment:
-Seachem Acid and Alkaline Buffer
-5 gallon bucket or mixing container
-pH tester, preferably an electronic one
-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 can use your tap water to mix/lower pH. Initial tap water pH is not as crucial 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.

Please let me know if you have any questions.

27th Nov 2008, 01:03 AM
Did you test GH and TDS after the mixing?

My new ADA tank has PH 5.x, KH 0, and I have to use Seachem Alkaline to raise PH to 6+ range, KH to 1-2. This raises my TDS as well.

27th Nov 2008, 01:18 AM
feiyang: No, I did not test TDS and GH after mixing. I suppose B. Macrostoma aren't as sensitive to those conditions as shrimp may be. I will test my current tank and post my readings.

27th Nov 2008, 02:57 AM
It's realy pitty that KH and GH was not tested.

16th Jan 2009, 10:11 AM
I think seachem neutral regulator would be both easier and safer in the long run,

yes you'd have ph 7.0 not 6.5 or less,

but at least it would be constantly stable,
i've been using neutral regulator for years with my other tanks for discus and general communitys and breeding, and it's just so easy, it binds ammonia and choramine and chlorine and heavy metals at the same time as buffering to 7.0
just disolve 1/4 teaspoon to each 10 litre bucket of water.. done water is ready to use.

I have used acid buffers in the past, but it's tricky, and if you have plants and other matter in the tank that is rotting, the PH can suddenly drop, i've experience fish deaths specifically because of the lack of stability when using buffers alone. Without constant monitoring and alot of expensive test equiptment it's pretty hard to keep it stable.

(my tap water is PH 7.3-8.0 depending on if I am being routed dam water or desalinated water)

just my thoughts.


8th Jul 2009, 03:07 AM

Ive used Seachem Acid Buffer to decrease Ph, but Kh goes below 1. And I wonder if I can keep CRS with a Kh<1.

Anyone using Seachem Acid Buffer could help?

In mi opinion is just like adding a common acid.

28th Jan 2010, 03:19 AM
so you are saying if use seachem neutral regulator they tap water with ph 7.5 and above will drop to 7.0 ph and will be stable?
Do you think using seachem neutral regulator to treat my tap water and keep PH in 7.0 for CRS will help to breed CRS?

is there any successful cases?


13th Apr 2010, 05:25 PM
Interesting read this. I have thought about getting an RO system, but decided to try rainwater collection in the meantime to experiment.

However I will try this Acid buffer and test using a electric ph reader and see how easy it is to attain a lower ph reading.

I live in London and the ph is around 7.5 and each month I will mix a small amount of RO water to reduce the ph level to 6.8.

18th Apr 2011, 01:17 PM

Any refinements/simplifications on your technique? Are you still doing this, or did you go with the easier neutral buffer route?

18th Apr 2011, 01:33 PM
Do you all tried this in shrimp tank? Safe to use in shrimp tank?

18th Apr 2011, 09:37 PM

Any refinements/simplifications on your technique? Are you still doing this, or did you go with the easier neutral buffer route?

No, I received an RO unit for free from a local club member and have not been using any chemicals to adjust water parameters since.