PH Level Dropping

Since the weather has turned cold here in Perth Australia over the last month my PH level has dropped continually down from 7 to around 5.5 - 5. I have adjusted it with Bi-Carb soda to bring it back up at a rate of about 1.5 Tsp per 1000 litres but then a week later it will have dropped again. All my other water levels are spot on. Can you tell me why this is happening as during the summer months it was OK. Is Bi-Carb soda the correct way to raise the levels? What can you suggest to maintain a steady level of PH? Thank you, look forward to your suggestions. -William I would do a water change and I would do it regularly. All your Koi are doing right now when they are hibernating is breathing. They breath in oxygen and exhale carbon dioxide. Carbon dioxide is acidic and will slowly eat away at carbonate levels in the water. As the carbonate levels go down, the water's ability to buffer acid also drops. That is why you pH keeps dropping. Doing a regular water change or adding Bi-Carb soda will keep the carbonate levels in your pond up. Share: Del.icio.us Digg Reddit

What is the right water temp for bio filter to start after winter season?

Your bio filter actually never shuts down, it just gets very efficient. This is due to the fact that cold water holds more oxygen, which is required to turn Ammonia into Nitrite and Nitrite into Nitrate. There will be a significant less amount of Nitrifying bacteria in the filter itself, because Koi's metabolism slows down to a crawl in cold water. As the water in your pond gets warmer in the spring, the number Nitrifying bacteria that live in your filter will increase. If you shut your filter system off in the fall, the bacteria would have all completely died off by now. It will take 4 - 6 weeks for Nitrosomonas and Nitrobacter to grow back. Make sure to test your water frequently to check that your filter is working properly and there isn't an increase of Ammonia levels. Don't forget to do a large water change in the spring too. The oxidization of Ammonia and Nitrite by Nitrifying bacteria liberates Hydrogen Ions, which will lower you pH. Over time this will diminish the carbonates in the water, which could lead to a pH crash. Share: Del.icio.us Digg Reddit