API

Aquarium Pharmaceuticals' Copper Test Kit tests copper levels in water from 0 to 4 ppm, and measures both free and chelated copper. Always monitor aquarium copper levels when medicating. For use in Freshwater or Saltwater Aquariums or Ponds.

• The accurate way to test aquarium quality
• Tests copper levels from 0 to 4 ppm
• Suitable for fresh and saltwater

Aquarium Pharmaceuticals Phosphate Test Kit allows you to easily and accurately measure the phosphate level and maintain a healthy aquarium or pond. It does 150 tests.

• High phosphate leads to algae growth
• Helps maintain clear and healthy water
• For fresh and saltwater

Why test your phosphate levels Well, phosphate can enter your aquarium through tap water, fish waste and decaying organics such as uneaten food or dead algae. As phosphate increases so does your chance of having unsightly algae and green water blooms. In salt water, phosphate can also inhabit the growth of corals and other reef building organisms.

Kit contains: two dropper bottles for accurate dispensing of test solutions, easy to read instructions and color charts, one non-staining glass test tube with snap-tight cap.

Range is as follows for freshwater and saltwater: 0.0 PPM, 0.5 PPM, 1.0 PPM, 2.0 PPM, 5.0 PPM, 10.0 PPM.

Aquarium Pharmaceuticals Fresh/Salt Water Carbonate Test Kit measures carbonate hardness, the measure of carbonate and bicarbonate concentrations in the water.

• Carbonate hardness test kit
• Monitor KH to prevent pH problems
• For freshwater aquariums

APIs carbonate hardness (KH) of aquarium water should be tested frequently, since water with a low KH is subject to rapid shifts in PH, greatly stressing fish and making them vulnerable to disease.

The proper KH levels is an important part of water quality and is necessary for the health of fish and the development and growth of aquarium plants. Kit contains dropper bottle for accurate dispensing of test solution, easy to read instructions and color chart, non-staining glass test tube with snap-tight cap.

The API Freshwater Hardness GH and KH Test Kit tests tap water and freshwater aquariums for general hardness (GH) and carbonate hardness (KH). Keeping these factors properly balanced creates a more healthy, natural environment for your freshwater aquarium fish.

• General and carbonate hardness test kit
• Monitor GH and KH to create a more natural habitat
• For freshwater aquariums

The Freshwater Hardness GH and KH Test Kit helps detect stress on fish caused by rapid pH shifts, which result from low KH levels and helps aquarists duplicate the natural habitat of their fish.

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API Stress Zyme Plus helps improve the development of the biological filter, as well as cleaning a dirty aquarium. API Stress Zyme contains millions of live, beneficial bacteria cultures to break down and destroy sludge in the gravel bed while keeping grass and plants clean.

• Keeps aquarium clean and reduces maintenance
• Improves bio filter at startup
• Made in the USA
• Great for fresh or saltwater

API Stress Zyme Plus breaks down organic compounds that can cause dangerous conditions such as ammonia and nitrite poisoning and low oxygen levels.

A continuing use of Stress Zyme will assure an active biological filter, cleaner aquarium, healthier fish, and an overall good water quality. You do not have to keep this product refrigerated. StressZyme can be used in Fresh or Saltwater aquariums and when setting up or maintaining aquarium. Additional features:

• Contains live bacteria to consume sludge
• Reduces aquarium maintenance
• Adds beneficial bacteria for a healthy aquarium
• All natural ingredients

When To Use: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter.

Directions: Shake well. To maintain a clean, healthy aquarium: add 1 tsp. (5 ml) per 10 US gallons (38 L) or 1/2 cup (120 ml) for each 240 US gallons (912 ml) of water weekly. For new aquariums to help boost the biological filter: double the dose, use at startup and for 2 additional weeks.

Dosage:
1 oz treats 60 gallons
4 oz treats 236 gallons
8 oz treats 480 gallons
16 oz treats 960 gallons
64 oz treats 3,786 gallons
4 gallons treats 30,240 gallons

API E.M. Erythromycin Powder treats a broad range of bacterial fish infections including hemorrhagic septicemia, fin and tail rot, mouth fungus (cotton mouth), open red sores and bacterial gill disease in freshwater and saltwater aquariums. Powdered fish health remedies allow easy dosing for easier, faster, and more effective treatment.

• Broad spectrum antibacterial fish treatment
• Allows treatment and control of bacterial fish infections
• Treats fin and tail rot, open red sores, mouth fungus, and more

This treatment can also be used with many parasite treatments to prevent secondary infections.

Active Ingredients: Erythromycin.

API E.M. Erythromycin Powder treats a broad range of bacterial fish infections including hemorrhagic septicemia, fin and tail rot, mouth fungus (cotton mouth), open red sores and bacterial gill disease in freshwater and saltwater aquariums. Powdered fish health remedies allow easy dosing for easier, faster, and more effective treatment.

• Broad spectrum antibacterial fish treatment
• Allows treatment and control of bacterial fish infections
• Treats fin and tail rot, open red sores, mouth fungus, and more

This treatment can also be used with many parasite treatments to prevent secondary infections.

Active Ingredients: Erythromycin.

API Tap Water Conditioner is a super-strength water conditioner that instantly removes chlorine and detoxifies heavy metals in tap water. Its highly concentrated formula is perfect for use when setting up a new aquarium or adding water.

• Removes chlorine and chloramines and detoxifies heavy metals
• Makes new tap water safe for fish
• Super strength, highly concentrated formula

Safe for all aquatic life. Heavy metals, such as copper, lead, and zinc, can be found in most tap water supplies. These metals are toxic to tropical fish; treating the aquarium when adding tap water reduces the risk of fish illness or death from these elements.

Directions: To remove chlorine and detoxify heavy metals: Add 1 teaspoon (5 ml) for each 100 gallons (380 L) of aquarium water. To detoxify chloramines: Add 1 teaspoon (5 ml) for each 30 gallons (114 L) of aquarium water.

API Tap Water Conditioner is a super-strength water conditioner that instantly removes chlorine and detoxifies heavy metals in tap water. Its highly concentrated formula is perfect for use when setting up a new aquarium or adding water.

• Removes chlorine and chloramines and detoxifies heavy metals
• Makes new tap water safe for fish
• Super strength, highly concentrated formula

Safe for all aquatic life. Heavy metals, such as copper, lead, and zinc, can be found in most tap water supplies. These metals are toxic to tropical fish; treating the aquarium when adding tap water reduces the risk of fish illness or death from these elements.

Directions: To remove chlorine and detoxify heavy metals: Add 1 teaspoon (5 ml) for each 100 gallons (380 L) of aquarium water. To detoxify chloramines: Add 1 teaspoon (5 ml) for each 30 gallons (114 L) of aquarium water.

API Tap Water Conditioner is a super-strength water conditioner that instantly removes chlorine and detoxifies heavy metals in tap water. Its highly concentrated formula is perfect for use when setting up a new aquarium or adding water.

• Removes chlorine and chloramines and detoxifies heavy metals
• Makes new tap water safe for fish
• Super strength, highly concentrated formula

Safe for all aquatic life. Heavy metals, such as copper, lead, and zinc, can be found in most tap water supplies. These metals are toxic to tropical fish; treating the aquarium when adding tap water reduces the risk of fish illness or death from these elements.

Directions: To remove chlorine and detoxify heavy metals: Add 1 teaspoon (5 ml) for each 100 gallons (380 L) of aquarium water. To detoxify chloramines: Add 1 teaspoon (5 ml) for each 30 gallons (114 L) of aquarium water.

API Tap Water Conditioner is a super-strength water conditioner that instantly removes chlorine and detoxifies heavy metals in tap water. Its highly concentrated formula is perfect for use when setting up a new aquarium or adding water.

• Removes chlorine and chloramines and detoxifies heavy metals
• Makes new tap water safe for fish
• Super strength, highly concentrated formula

Safe for all aquatic life. Heavy metals, such as copper, lead, and zinc, can be found in most tap water supplies. These metals are toxic to tropical fish; treating the aquarium when adding tap water reduces the risk of fish illness or death from these elements.

Directions: To remove chlorine and detoxify heavy metals: Add 1 teaspoon (5 ml) for each 100 gallons (380 L) of aquarium water. To detoxify chloramines: Add 1 teaspoon (5 ml) for each 30 gallons (114 L) of aquarium water.

API Tap Water Conditioner is a super-strength water conditioner that instantly removes chlorine and detoxifies heavy metals in tap water. Its highly concentrated formula is perfect for use when setting up a new aquarium or adding water.

• Removes chlorine and chloramines and detoxifies heavy metals
• Makes new tap water safe for fish
• Super strength, highly concentrated formula

Safe for all aquatic life. Heavy metals, such as copper, lead, and zinc, can be found in most tap water supplies. These metals are toxic to tropical fish; treating the aquarium when adding tap water reduces the risk of fish illness or death from these elements.

Directions: To remove chlorine and detoxify heavy metals: Add 1 teaspoon (5 ml) for each 100 gallons (380 L) of aquarium water. To detoxify chloramines: Add 1 teaspoon (5 ml) for each 30 gallons (114 L) of aquarium water.

API Tap Water Conditioner is a super-strength water conditioner that instantly removes chlorine and detoxifies heavy metals in tap water. Its highly concentrated formula is perfect for use when setting up a new aquarium or adding water.

• Removes chlorine and chloramines and detoxifies heavy metals
• Makes new tap water safe for fish
• Super strength, highly concentrated formula

Safe for all aquatic life. Heavy metals, such as copper, lead, and zinc, can be found in most tap water supplies. These metals are toxic to tropical fish; treating the aquarium when adding tap water reduces the risk of fish illness or death from these elements.

Directions: To remove chlorine and detoxify heavy metals: Add 1 teaspoon (5 ml) for each 100 gallons (380 L) of aquarium water. To detoxify chloramines: Add 1 teaspoon (5 ml) for each 30 gallons (114 L) of aquarium water.

The API Water Softener Pillow contains ion exchange resins to remove calcium, magnesium and soluble heavy metal ions, including iron and copper. This reduces white, crusty deposits on aquarium surfaces and increases the lifespan of your equipment.

• Softens water by removing calcium, magnesium and heavy metals
• For freshwater aquariums
• Fully rechargeable 2 oz treats up to 20 gallons

Reduces calcium and magnesium content, lowering general hardness (GH) and softening water without adding harmful chemicals. The convenient pouch is fully rechargeable.

When to Use: When starting or maintaining an aquarium or when testing indicates water hardness above the desired level.

Directions: Rinse pouch under tap water. Place pouch in path of water flow in the aquarium filter. The activity of the pillow lasts 48 hours. After 48 hours, recharging is necessary.

Recharging: Dissolve 3 tablespoon of aquarium salt in 7 oz of tap water. Rinse pouch in tap water, then soak in the salt solution for 2 hours. Place back in filter

API Ammo Lock works instantly to detoxify ammonia produced by fish waste, and remove chlorine and chloramine from tap water, while eliminating ammonia stress and protecting healthy gill function.

• Scientifically proven to protect fish cells against ammonia
• Detoxifies ammonia in aquariums and Works Instantly
• Safe for all fish, invertebrates and plants and it can be used with medications

Ammo Lock does not remove ammonia, it simply converts it to a non-toxic form. The neutral solution will not change water pH. The biological filter will then consume the non-toxic ammonia, converting it to nitrite then to nitrate. Each bottle treats 240 gallons of fresh or salt water.

Dosage:
4 oz treats 236 gallons
8 oz treats 474 gallons
16 oz treats 946 gallons

API Ammo Lock works instantly to detoxify ammonia produced by fish waste, and remove chlorine and chloramine from tap water, while eliminating ammonia stress and protecting healthy gill function.

• Scientifically proven to protect fish cells against ammonia
• Detoxifies ammonia in aquariums and Works Instantly
• Safe for all fish, invertebrates and plants and it can be used with medications

Ammo Lock does not remove ammonia, it simply converts it to a non-toxic form. The neutral solution will not change water pH. The biological filter will then consume the non-toxic ammonia, converting it to nitrite then to nitrate. Each bottle treats 240 gallons of fresh or salt water.

Dosage:
4 oz treats 236 gallons
8 oz treats 474 gallons
16 oz treats 946 gallons

API Ammo Lock works instantly to detoxify ammonia produced by fish waste, and remove chlorine and chloramine from tap water, while eliminating ammonia stress and protecting healthy gill function.

• Scientifically proven to protect fish cells against ammonia
• Detoxifies ammonia in aquariums and Works Instantly
• Safe for all fish, invertebrates and plants and it can be used with medications

Ammo Lock does not remove ammonia, it simply converts it to a non-toxic form. The neutral solution will not change water pH. The biological filter will then consume the non-toxic ammonia, converting it to nitrite then to nitrate. Each bottle treats 240 gallons of fresh or salt water.

Dosage:
4 oz treats 236 gallons
8 oz treats 474 gallons
16 oz treats 946 gallons

APIs Hand Held Algae Pad is a indestructible cleaning pad made to reach every nook, cranny, corner, and anywhere else algae may be hiding in your aquarium. For acrylic aquariums only.

• Made to reach all of your tanks nooks and crannies
• Quickly removes unsightly algae
• Suitable for acrylic aquariums

If aquarium gravel is picked up on pad rinse before use. Gravel will scratch acrylic surfaces. Do not use extreme pressure.

APIs Algae Scraper is an incredibly durable algae scraper for cleaning aquarium walls. Made with an 18" long, strong handle, and features a scrubbing pad and hard scraping tip.

• Incredibly durable algae scraper
• Long, strong handle
• Features a scrubbing pad and hard scraping tip

Removes even the toughest algae quickly and easily. For acrylic aquariums.

API Proper pH 6.5 Freshwater Aquarium pH Stabilizer sets and holds pH to 6.5 and resists pH rebound. pH is the measure of the acidity of water, on a scale ranging from 0-14. ApH of 0 is the most acidic, while a pH of 14 is the most alkaline. Water with a pH of 7.0 is considered "neutral". Along with keeping your pH at the correct levels Proper pH 6.5 also removes chlorine, neutralizes chloramines, adds electrolytes & detoxifies heavy metals in freshwater aquariums. It is perfect for soft water species including Tetras, discus, Rasboras, and Angelfish.

• Sets & stabilizes pH to 6.5
• Removes chlorine
• Ideal for Tetras, Discus and Angelfish
• Use when setting up a new tank, adjusting pH in an established tank, and water changes

API Proper pH 6.5 Freshwater Aquarium pH Stabilizer sets and holds pH to 6.5 and resists pH rebound. pH is the measure of the acidity of water, on a scale ranging from 0-14. ApH of 0 is the most acidic, while a pH of 14 is the most alkaline. Water with a pH of 7.0 is considered "neutral". Along with keeping your pH at the correct levels Proper pH 6.5 also removes chlorine, neutralizes chloramines, adds electrolytes & detoxifies heavy metals in freshwater aquariums. It is perfect for soft water species including Tetras, discus, Rasboras, and Angelfish.

• Sets & stabilizes pH to 6.5
• Removes chlorine
• Ideal for Tetras, Discus and Angelfish
• Use when setting up a new tank, adjusting pH in an established tank, and water changes

API Proper pH 6.5 Freshwater Aquarium pH Stabilizer sets and holds pH to 6.5 and resists pH rebound. pH is the measure of the acidity of water, on a scale ranging from 0-14. ApH of 0 is the most acidic, while a pH of 14 is the most alkaline. Water with a pH of 7.0 is considered "neutral". Along with keeping your pH at the correct levels Proper pH 6.5 also removes chlorine, neutralizes chloramines, adds electrolytes & detoxifies heavy metals in freshwater aquariums. It is perfect for soft water species including Tetras, discus, Rasboras, and Angelfish.

• Sets & stabilizes pH to 6.5
• Removes chlorine
• Ideal for Tetras, Discus and Angelfish
• Use when setting up a new tank, adjusting pH in an established tank, and water changes