I have a 9 inch or so common in a 20ish gallon rubbermaid tub, waiting for the weather to warm up so he can move into his pond. I was checking the water params on all my tanks to determine the water changes for tomorrow and his tub is in sorry condition.

For starters the ph is at or below 6.0
The cycle is completely shot now and I am showing large ammounts of ammonia,nitrite, and nitrate. I have primed the water to detox the ammonia and nitrite.

I need to do a massive water change but the ph out of the tap here is 7.4 and I do not want to shock the fish. Usually we have been doung 50-75% changes once a week and that has held untill this week. I am going to add crushed coral to the filter for the tub today and that should prevent future crashes.

How much water should I change out at a time to prevent harming the fish? Currently he does not seem too bothered by the ph, but the cycle crashing too has me worried.

Do not raise the pH in the tankwater more than 0.2 per hour or two. To do this, I would only change 15% of the water every 2 hours until you get the pH back up to what the tapwater is at. But, whatever you do, utilize Prime OR Amquel plus as per the directions to detoxify any of the ammonia and nitrItes that are forming because of the re-establishment of your bio-filter.


I hope this helps!

Paul

Thank you for the help. I had already dosed with prime for what was in the tub already, and now the water gets checked every day for the cycle and to watch for another ph drop.