API PH Down - 118ml
API pH Down for Freshwater Aquariums API has been an industry leader in fish care, nutrition, treatments, testing and pond products for over 50 years, giving them a keen insight into your aquarium and its needs - making them the clear choice for fish enthusiasts around the world. API pH DOWN pH adjuster lowers the pH to make freshwater aquariums more acidic for fish and plants when levels rise too high. pH is the measure of acidic or alkaline conditions in water. Where a value of 7.0 corresponds to a neutral pH, pH values above 7.0 are considered alkaline, and pH values below 7.0 are considered acidic. Different fish need different pH levels to be healthy, so it is important to test your water regularly to ensure pH levels fall where they should. pH DOWN pH adjuster is fast-acting, colourless, easy to use, and will not cloud aquarium water. Because it is phosphate-free and nitrate-free, pH DOWN pH adjuster will not encourage algae growth. Water treatment to lower the pH (make the water more acidic) Use when the pH rises too high Suitable for freshwater aquariums Fast-acting, colourless, and will not cloud the water After something different? View all Fish Water Care Supplies. New to fish care? View our guide to Setting Up a Fishtank.
API pH Down for Freshwater Aquariums API has been an industry leader in fish care, nutrition, treatments, testing and pond products for over 50 years, giving them a keen insight into your aquarium and its needs - making them the clear choice for fish enthusiasts around the world. API pH DOWN pH adjuster lowers the pH to make freshwater aquariums more acidic for fish and plants when levels rise too high. pH is the measure of acidic or alkaline conditions in water. Where a value of 7.0 corresponds to a neutral pH, pH values above 7.0 are considered alkaline, and pH values below 7.0 are considered acidic. Different fish need different pH levels to be healthy, so it is important to test your water regularly to ensure pH levels fall where they should. pH DOWN pH adjuster is fast-acting, colourless, easy to use, and will not cloud aquarium water. Because it is phosphate-free and nitrate-free, pH DOWN pH adjuster will not encourage algae growth. Water treatment to lower the pH (make the water more acidic) Use when the pH rises too high Suitable for freshwater aquariums Fast-acting, colourless, and will not cloud the water After something different? View all Fish Water Care Supplies. New to fish care? View our guide to Setting Up a Fishtank.
API pH Down for Freshwater Aquariums API has been an industry leader in fish care, nutrition, treatments, testing and pond products for over 50 years, giving them a keen insight into your aquarium and its needs - making them the clear choice for fish enthusiasts around the world. API pH DOWN pH adjuster lowers the pH to make freshwater aquariums more acidic for fish and plants when levels rise too high. pH is the measure of acidic or alkaline conditions in water. Where a value of 7.0 corresponds to a neutral pH, pH values above 7.0 are considered alkaline, and pH values below 7.0 are considered acidic. Different fish need different pH levels to be healthy, so it is important to test your water regularly to ensure pH levels fall where they should. pH DOWN pH adjuster is fast-acting, colourless, easy to use, and will not cloud aquarium water. Because it is phosphate-free and nitrate-free, pH DOWN pH adjuster will not encourage algae growth. Water treatment to lower the pH (make the water more acidic) Use when the pH rises too high Suitable for freshwater aquariums Fast-acting, colourless, and will not cloud the water After something different? View all Fish Water Care Supplies. New to fish care? View our guide to Setting Up a Fishtank.
API pH Down for Freshwater Aquariums API has been an industry leader in fish care, nutrition, treatments, testing and pond products for over 50 years, giving them a keen insight into your aquarium and its needs - making them the clear choice for fish enthusiasts around the world. API pH DOWN pH adjuster lowers the pH to make freshwater aquariums more acidic for fish and plants when levels rise too high. pH is the measure of acidic or alkaline conditions in water. Where a value of 7.0 corresponds to a neutral pH, pH values above 7.0 are considered alkaline, and pH values below 7.0 are considered acidic. Different fish need different pH levels to be healthy, so it is important to test your water regularly to ensure pH levels fall where they should. pH DOWN pH adjuster is fast-acting, colourless, easy to use, and will not cloud aquarium water. Because it is phosphate-free and nitrate-free, pH DOWN pH adjuster will not encourage algae growth. Water treatment to lower the pH (make the water more acidic) Use when the pH rises too high Suitable for freshwater aquariums Fast-acting, colourless, and will not cloud the water After something different? View all Fish Water Care Supplies. New to fish care? View our guide to Setting Up a Fishtank.
in 35 offers
The lowest price for API PH Down - 118ml right now is $12.00 at Aquaristic Online, compared across 31 retailers.
The all-time low was $8.15 on 7 May 2026 — today's price is 47% above the lowest ever. It has been notably cheaper before — worth setting a price alert.
Prices last updated 28 June 2026.
Last updated at 28/06/2026 16:58:11
API pH Down 118ml – Safely Lower Aquarium pH | Aquaristic Online
Delivery $14
API PH Down Freshwater Aquarium Water Treatment 118ml
Delivery between 1–7 July $6.31
API pH DOWN Freshwater Aquarium Water pH Reducing Solution 4-Ounce Bottle
Delivery between 5–8 July $29
API Ph Down 118ml
API pH DOWN - 118ML
API pH Down 118mL
API pH Down 118mL
30-day returns
API pH Down Liquid - AquaticSupplies.com.au 118ml
Delivery between 2–7 July $11.95
API pH Down 118ml
Delivery on orders $50+
API pH Down 118ml
Delivery between Tue – Wed $10.67
originally posted on walmart.com
excellent product. worked as advertised and shipping was on time. will buy again
originally posted on petco.com
We have very "hard" water due since it comes out of a limestone aquifer. Our house is equipped with a softener, but the pH of our tank still comes out to around 8.2, even with driftwood tannins. Used this every day for 2 weeks and the pH never changed.
originally posted on petco.com
I had a brand new setup (no fish) where the ph was about 7.8. in my 40 gallon tank I used about half the bottle and saw no change in ph. Only after I added a general water balancing agent did I see the ph drop. If this is really sulfuric acid in a bottle, the ph should've dropped significantly with how much I used (I mixed the water manually and tested after about 10 minutes so I know nothing in the tank was re-raising the ph)
| Product dimensions | 3.81 x 3.81 x 13.34 cm; 136.08 Grams |
| Country of origin | USA |
| Is discontinued by manufacturer | No |
| Liquid volume | 4 Fluid Ounces |
| Target species | Fish |
API pH Down 118ml – Safely Lower Aquarium pH | Aquaristic Online
Delivery $14
API PH Down Freshwater Aquarium Water Treatment 118ml
Delivery between 1–7 July $6.31
API pH DOWN Freshwater Aquarium Water pH Reducing Solution 4-Ounce Bottle
Delivery between 5–8 July $29
API Ph Down 118ml
API pH DOWN - 118ML
excellent product. worked as advertised and shipping was on time. will buy again
We have very "hard" water due since it comes out of a limestone aquifer. Our house is equipped with a softener, but the pH of our tank still comes out to around 8.2, even with driftwood tannins. Used this every day for 2 weeks and the pH never changed.
I had a brand new setup (no fish) where the ph was about 7.8. in my 40 gallon tank I used about half the bottle and saw no change in ph. Only after I added a general water balancing agent did I see the ph drop. If this is really sulfuric acid in a bottle, the ph should've dropped significantly with how much I used (I mixed the water manually and tested after about 10 minutes so I know nothing in the tank was re-raising the ph)
I am on a well. My water checks out at 28 grains hardness. I have a water softener which does an excellent job but I still have to use this in the aquarium. 55 gal tank I had to treat it twice to get the change needed.
The bottle was not sealed. I dont know what I actually got. Product not worth the $ even if it was sealed. Just use vinegar.
The water where I live is quite alkaline, I wasn’t able to do anything to resolve this issue. Thanks to indefur, I got a product which could help me lower down the pH of my planted tank.
Goldfish are a lot harder to keep than people realize. It is easy for them to have problems with water quality and need frequent water changes. This pH Down helps keep the pH right, especially in my area, where we have hard water. I use it weekly!
After testing my water, the pH was high and the alkalinity tested high as well. I used pH down and the pH went up. I think the bottles are switched, and I don't want my fish to die because of a factory mistake!
This worked excellent for my tank although I did have to do a 2nd dose it really works. This was a new tank that had not been cycled yet and it brought down the ph levels to make it safe for my fish
If you want to lower the pH in your water, this product is all you need. It doesn’t take much, my tapwater is way up in the 7pH maybe even as high as 8pH range, I feel up a gallon of water then add 1/3 Tsp that’s 1.65 milliliters of pH down and my gallon of water is around 6.2 - 6.3. Like I said you don’t need to use much. Like all things it takes some getting used to but once you get it down pat you’ll have no problem using this product.
| Product dimensions | 3.81 x 3.81 x 13.34 cm; 136.08 Grams |
| Country of origin | USA |
| Is discontinued by manufacturer | No |
| Liquid volume | 4 Fluid Ounces |
| Target species | Fish |
