10 Simple Tricks That Will Save Your Fish Tank, by Pieter Van Dijk on YouTube. 20 min 5 s.
- Video length
- 20 min 5 s
- Time to do it
- 1 hour setup, then 2 weeks of
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Test your water with a liquid pH test kit before you change anything. Note the pH, KH and nitrate readings so you can compare them later.
Change 20 to 30 percent of the water with dechlorinated tap water at the same temperature. This drops nitrate and the carbonate buffers that keep pH high.
Boil a piece of driftwood for 10 minutes, let it cool, then sink it in the tank. It releases tannins that slowly lower pH and KH and gives bacteria surface to grow on.
Add fast-growing stem plants such as hornwort or elodea. They use up nitrate and carbon dioxide, which keeps pH steadier between water changes.
Run an air stone or add surface movement, especially at night. Plants release carbon dioxide in the dark, and extra oxygen flow reduces the overnight pH drop.
Put the lights on a timer for 6 to 8 hours a day. Long light periods drive algae blooms that push pH around. For green water, black out the tank for 3 days.
Re-test after 24 hours, then every 2 to 3 days. Aim for no more than 0.2 to 0.3 of a pH point per day so the fish are not shocked.
Stop adjusting once the reading is stable and your fish look calm. A steady pH suits most community fish better than a number that swings up and down.
Tips and common mistakes
Skip bottled pH-down chemicals, they drop the reading fast and cause swings that stress fish more than a slightly high pH does.
Check KH as well, because hard water with high carbonate hardness pulls pH back up within a day.
Add tannins gradually, since a large piece of fresh driftwood can stain the water brown for weeks.
Never change more than a third of the water at once while you are adjusting pH.
Questions
How fast can I lower aquarium pH?
No more than 0.2 to 0.3 of a point per day. Slow changes give fish and filter bacteria time to adjust.
Does driftwood lower pH on its own?
Yes, it releases tannic acid, but the effect is gentle and depends on your KH. Soft water with low KH shifts far more than hard water.
What if my fish look fine at a high pH?
Then leave it alone. Stable readings matter more than matching a number from a book, and most farm-bred fish adapt to local tap water.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
