---
product_id: 48174941
title: "pH DOWN Freshwater Aquarium Water pH Reducing Solution 118 ml Bottle"
brand: "api"
price: "HK$153"
currency: HKD
in_stock: true
reviews_count: 13
category: "Api"
url: https://www.desertcart.hk/products/48174941-ph-down-freshwater-aquarium-water-ph-reducing-solution-118-ml
store_origin: HK
region: Hong Kong
---

# Phosphate-free, plant-safe Fish-friendly formula Precise pH control pH DOWN Freshwater Aquarium Water pH Reducing Solution 118 ml Bottle

**Brand:** api
**Price:** HK$153
**Availability:** ✅ In Stock

## Summary

> 🐟 Keep your aquatic world thriving with precision pH control!

## Quick Answers

- **What is this?** pH DOWN Freshwater Aquarium Water pH Reducing Solution 118 ml Bottle by api
- **How much does it cost?** HK$153 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hk](https://www.desertcart.hk/products/48174941-ph-down-freshwater-aquarium-water-ph-reducing-solution-118-ml)

## Best For

- api enthusiasts

## Why This Product

- Trusted api brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Effortless Weekly Maintenance:** Use weekly to keep your freshwater aquarium’s pH perfectly balanced
- • **Safe for Your Aquatic Ecosystem:** Phosphate-free formula that won’t promote algae growth or harm plants and fish
- • **Compact & Convenient 118 ml Bottle:** Easy dosing for precise adjustments without overcorrection
- • **Trusted by Aquarists for Over 50 Years:** API’s research-driven solution ensures reliable, consistent results
- • **Balance Your Aquarium’s pH Like a Pro:** Slowly neutralizes alkaline substances for stable water chemistry

## Overview

API pH DOWN Freshwater Aquarium Water pH Reducing Solution is a phosphate-free liquid formula designed to safely lower and stabilize pH levels in freshwater aquariums. Ideal for maintaining optimal water conditions for tropical fish and plants, it neutralizes alkaline substances without promoting algae growth. Trusted for over 50 years, this 118 ml bottle offers precise, easy-to-use dosing for weekly pH adjustments, ensuring a healthy, vibrant aquatic environment.

## Description

Product Description pH is the measure of acidity of water, on a scale ranging from 0 to 14. A pH of 0 is the most acidic, while a pH of 14 is the most alkaline. Different geographies have different tap water conditions with different pH levels, while fish require a specific pH level to thrive. A pH of 7.0 is ideal when keeping a community aquarium containing a variety of tropical fish. Goldfish and livebearers prefer a pH of 7.5. Many desertcartian fish, like angelfish and neon tetras, prefer a pH of 6.5 to 6.8. Mollies and swordtails thrive at pH 7.2 to 7.5. API pH DOWN Freshwater Aquarium Water pH Reducing Solution lowers aquarium pH in freshwater aquariums to desired level. Safe for fish and plants. Use when setting up a new aquarium, adjusting pH, or changing water. pH in an aquarium can fluctuate due to fish waste, uneaten food and addition of tap water. It is recommended to test water for pH weekly. With API Aquarium products, it’s easy to keep a beautiful saltwater, freshwater or reef aquarium. For over 50 years, API has been creating innovative, research-driven solutions that make it easier to care for your fish and aquarium. API Aquarium Treatment Supplies are designed to work in conjunction with each other to provide best results to control algae, promote healthy bacterial growth and help control and cure fish diseases and conditions such as ich and fin rot. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. With API, you can spend more time admiring your fish, and less time scrubbing your tank. Make sure to use all products as directed in order to ensure the best results. Directions 1. Test water weekly using a separate test kit. 2. If the pH level is too high, use the API pH DOWN Freshwater Aquarium Water pH Reducing Solution to correct it. 3. Slowly neutralize alkaline substances that cause high water pH. 4. Use sparingly, as directed, to avoid lowering the pH below the desired level. 5. Always follow the instructions on the product label and packaging. P.when('A').execute(function(A) { A.on('a:expander:toggle_description:toggle:collapse', function(data) { window.scroll(0, data.expander.$expander[0].offsetTop-100); }); }); Box Contains 1 x API pH Down Aquarium Freshwater pH Reducing Solution 118 ml See more

Review: Quality assured. - I was in urgent need of this product and due to the excellence of desertcart it was delivered to me very quickly thus helping me stabilise the problem in my aquarium. The product is proven quality, reliable and so easy to use and I purchased it at a very competitive price too.
Review: Works but small changes - Works great ups kh more and quicker than ph, notice change in 1-2 days. Recommend cleaning filter and pouring it into the filter for quicker change.

## Features

- Causes severe skin burns and eye damage.
- May be corrosive to metals.
- May cause cancer.
- Contains one (1) API pH DOWN Freshwater Aquarium Water pH Reducing Solution 118 ml Bottle
- Lowers freshwater aquarium water pH with a phosphate-free formula
- Does not promote algae growth with pH adjustments and is safe for plants and fish
- Slowly neutralizes alkaline substances that cause high water pH
- Test water weekly and use to correct pH level in freshwater aquariums

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0002AQMV4 |
| Batteries Included | No |
| Batteries required | No |
| Best Sellers Rank | 2,477 in Pet Supplies ( See Top 100 in Pet Supplies ) 27 in Aquarium Water Treatments |
| Customer Reviews | 4.6 4.6 out of 5 stars (3,346) |
| Date First Available | 15 Nov. 2010 |
| Delivery information | We cannot deliver certain products outside mainland UK ( Details ). We will only be able to confirm if this product can be delivered to your chosen address when you enter your delivery address at checkout. |
| Item Form | Liquid |
| Item Weight | 136 g |
| Item model number | 30C |
| Number of Items | 1 |
| Pet Type | Fish |
| Product Dimensions | 3.81 x 3.81 x 13.34 cm; 136.08 g |
| Quantity | 1 |
| Size | 118 ml |
| Volume | 4 |

## Product Details

- **Brand:** API
- **Item form:** Liquid
- **Item weight:** 136 g
- **Liquid volume:** 118 Millilitres
- **Manufacturer:** API

## Images

![pH DOWN Freshwater Aquarium Water pH Reducing Solution 118 ml Bottle - Image 1](https://m.media-amazon.com/images/I/71bFz9XJJBL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Quality assured.
*by P***H on 20 October 2025*

I was in urgent need of this product and due to the excellence of Amazon it was delivered to me very quickly thus helping me stabilise the problem in my aquarium. The product is proven quality, reliable and so easy to use and I purchased it at a very competitive price too.

### ⭐⭐⭐⭐⭐ Works but small changes
*by H***Y on 17 April 2025*

Works great ups kh more and quicker than ph, notice change in 1-2 days. Recommend cleaning filter and pouring it into the filter for quicker change.

### ⭐⭐⭐⭐ Works as described
*by C***C on 2 May 2022*

Lowers ph but sometimes this just hides the cause! So if you are looking into this make sure it’s not another factor? Do you have too many fish? Is your tap safe not right? Need a new filter pad?

## Frequently Bought Together

- API pH DOWN Freshwater Aquarium Water pH Reducing Solution 4-Ounce Bottle
- API AMMONIA 130-Test Freshwater and Saltwater Aquarium Water Test Kit

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**Shop now:** [https://www.desertcart.hk/products/48174941-ph-down-freshwater-aquarium-water-ph-reducing-solution-118-ml](https://www.desertcart.hk/products/48174941-ph-down-freshwater-aquarium-water-ph-reducing-solution-118-ml)

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*Product available on Desertcart Hong Kong*
*Store origin: HK*
*Last updated: 2026-02-20*