What are some natural ways to lower the pH in a freshwater aquarium?

Question

The pH has been 8.4 for a couple weeks. I'm gradually reducing the temperature every day to get it down to 75 degrees (from 80.) Both factors are causing the remaining amount of ammonia (that I'm treating with water changes) to become more and more toxic, so this is not about adding more fish and adjusting for them. I really don't want to use chemicals unless I have to. Thank you.

TH: 250+

CH: 120

KH..........

Bear with me... I'm using test strips instead of the liquid drop tests. So Alkalinity is 120. (I'm guessing KH is the same thing?)

Answer 1

You are right that dropping the temperature and the pH will help the balance of NH4 to NH3 and that chemicals can certainly mask those results in an attempt to lower pH. You don't state your total and carbonate hardness readings, but no doubt you are aware of the relationship between carbonate hardness and pH. The most natural ways to lower pH are unfortunately also among the slowest especially if you are fighting a high carbonate hardness. Peat moss and driftwood are both ways to slowly lower the pH in a tank. Including peat moss, oak bark or cork bark in the filter will increase the speed at which these materials are able to affect pH. Obviously, the addition of almost any acid will help you drop the pH, so you may consider the use of something like distilled vinegar to assist in overcoming the carbonate hardness initially.

You can also collect and inject CO2 gas for a temporary lowering of pH, but care would have to be exercised to prevent the lowering of dissolved2 below the fishes tolerance.

Also the mixing of distilled water into the tank will lower both pH and hardness and would lead to the fastest and most stable result. This could be done as a first step and allow the peat moss to complete the process and as time continues you could slowly use less distilled water and pretreat your water for changes with peat filtration.

MM

Answer 2

Peat moss in the filter, and driftwood. But honestly, I wouldn't worry too much about the PH. Most freshwater aquarium fish can acclimate to a very wide PH range. Changing it too rapidly will only stress out your fish. I would worry more about the ammonia. Keep doing those water changes until your tank is cycled!

One more thought--don't add PH reducing chemicals. This generally causes your PH to fluctuate from water change to water change. A fluctuating PH is much, much more harmful to your fish than a constant one, even if the constant one is a little high.

Answer 3

As temp and pH drop, ammonia becomes less toxic. What is the pH from the tap?
Peat Moss will drop pH. http://freshaquarium.about.com/cs/waterchemsitry/a/mathcph.htm

Answer 4

The most effective way is to use ph lower chemicals. It does no harm to the fish. I don't remember the name of the brand, but you can purchase from this website http://www.drsfostersmith.com
They ship pretty fast and package really well. Price is much cheaper than retail stores.