In Perth we are fairly lucky with our tap water that it already comes with ~70mg/L of KH (carbonate hardness also known as [the pH] buffering capacity of water). Sometimes a bit more, sometimes a bit less. Provided that we carry out regular aquarium maintenance, we ought not run into issues with pH becoming too acidic because this level of KH should buffer against this. But did you know that this KH will be consumed and decrease over time? When this happens, your pH can fluctuate wildly, causing stress to the fish. Depending on several factors, your pH could drop to as low as 4.5! Very nasty for many fish.
What are some clues that might lead you suspect this could be occurring? Those species intolerant of low pH will develop excess white opaque mucus over their bodies and around the edges of their gill covers. They would become lethargic and hold their fins clamped to their body. The base of Their fins, especially their pectoral and pelvic fins will become congested. Fish will appear disoriented and lose interest in food. You will start to lose fish.
A quick water test would reveal a very low pH. Then a quick KH test would point to the reason for the low pH.
What to do? You will need to act quickly and slowly at the same time. ????
Act quickly to obtain buffering salts. But act slowly in terms of gradually increasing the KH and pH so as not to create more stress in the fish. Speak with your veterinarian or local fish shop for advice on the best combination of buffers for your individual system.
What are common sequelae such a condition? Fish may succumb to secondary bacterial infection and so antibiotics may be indicated.
The bio-filter may be destroyed by the low pH and so you’ll need to treat your system as a “new tank” in terms of the nitrogen cycle.
Also a note of warning whenever you use antibiotics is that it will whack your bio filter around and so it is very important that you conduct daily water testing especially for levels of ammonia and nitrite. Feeding should be reduced while the biofilter re-establishes itself, water changes conducted as necessary and bacteria starter cultures may be indicated at the completion of treatment.
Make sure you get a good set of water test kits.
