Aquarium Pharmaceuticals Tap Water Filter

Read 34 Reviews Write a Review


This item has been discontinued.

Aquarium Pharmaceuticals, API, MARS Fishcare

* Formerly named “Tap Water Purifier”

An easy-to-use, single-cartridge tap water filtration system that removes impurities from tap water, making perfect, deionized aquarium water. Filter resin changes color when it`s time to replace cartridge. Used cartridge can be replaced without tools in minutes. Comes fully assembled and attaches to any faucet in seconds. Includes 4 oz. bottles of Electro-Right and pH Adjuster to treat the filtered water, faucet adapter and tubing. For freshwater, saltwater, African cichlid or community aquariums.

How many gallons of water will the Tap Water Filter make?
The amount of deionized (DI) water produced by the Tap Water Filter depends entirely on the level of minerals, heavy metals, phosphate, nitrate, etc. that is in your tap water. Each cartridge has a fixed ion exchange capacity. In New York City, for example, aquarists can produce up to 300 gallons of DI water with a single cartridge. An aquarist in northern New Jersey, however, made 15 gallons of water. An analysis of the NJ water showed very high levels of copper, zinc, phosphate, nitrite, and nitrate in addition to the normal hardness minerals. A heavily polluted water source will use up a cartridge much sooner than a water supply low in minerals and pollutants. Most aquarists produce somewhere between 50 and 150 gallons per cartridge.

My original cartridge made 75 gallons of deionized water, the second cartridge made only 50 gallons. Why?
The level of dissolved minerals and pollutants in tap water can vary daily. The level of these dissolved substances is measured as Total Dissolved Solids (TDS). The tap water in our laboratory varies from 200 to 400 ppm TDS on a daily basis. Our Quality Control Department pulls Tap Water Filters off the production lines and tests them with our tap water. They have to know the TDS of the tap water the day they test the cartridges. Why? A jump in TDS from 200 to 400 ppm means that a cartridge will produce only half as much water as the day before. It all depends on the quality of the incoming tap water. It would be unusual if you did get exactly the same number of gallons out of every cartridge!

Will a home water softener system help the Tap Water Filter make more deionized water?>
No. Water softeners simply exchange sodium ions for calcium and magnesium ions. The softener is just trading one chemical (sodium) for another (calcium and magnesium). The softened water contains the same amount of dissolved substances as the un-softened hard water.

Can I run reverse osmosis water through the Tap Water Filter?
Yes. Reverse osmosis (RO) systems can significantly reduce Total Dissolved Solids (TDS) levels if properly maintained. RO, however, often lets through chemicals that the Tap Water Filter will remove and many aquarists run their RO water through the Tap Water Filter to scavenge out the traces of nitrate, phosphate, silicate, etc. that the RO did not remove. Running RO water through the Tap Water Filter will ensure the best water quality and extend the life of the cartridges. DO NOT connect the Tap Water Filter in-between an RO system and a pressurized storage tank. The Tap Water Filter is a low-pressure system and cannot stand the pressure of a closed RO system. Simply let the RO water pass through the Tap Water Filter and collect the water in a bucket or storage container.

Sometimes I get an open space just above the carbon bed. Why?
The open space forms as the resin compacts in the cartridge. We strive to pack the resin as tightly as possible to avoid the compaction space. An open space is not detrimental to water quality. You might also see some of the resins settling down into the open space. A small amount of resin swirling in the open gap is acceptable. The entire resin bed, however, should not separate.

Why can t I drink the water made with the Tap Water Filter?
We state on the package that the Tap Water Filter is not intended for human consumption. No doubt you ve heard about bacterial and parasitic contamination of drinking water. The Tap Water Filter does not remove or kill bacteria or parasites that may contaminate drinking water. If your drinking water was contaminated with bacteria or parasites, the Tap Water Filter would not produce safe drinking water. Recent studies have shown that tap water filtration systems sold for making drinking water very quickly become contaminated by bacteria. This is especially true of reverse osmosis filters. Any tap water filter used to make drinking water needs to be disinfected every six months. This includes the filter housings and tubing. Therefore, use the Tap Water Filter only for your aquarium.

Do I need to use Electro-Right and pH Adjuster when making saltwater?
No. Your synthetic saltwater mix should contain all the buffers, electrolytes and trace elements necessary for the aquarium. You can add special marine buffers like proper pH 8.2 and trace elements in the aquarium later. When topping off the aquarium it is not necessary to use Electro-Right and pH Adjuster.

When I make saltwater, the pH never stabilizes to 8.2-8.4. Does deionized water lower pH?
No. Deionized water has no pH adjusting properties. The pH of your marine aquarium is regulated primarily by the buffer system created by the synthetic sea salts. If the salt manufacturer does not properly blend in the buffer salts, the final solution will have a pH other than 8.2-8.4. Some synthetic sea salts consistently run "low" or "high" depending on the manufacturer s formula and blending techniques. Tap water may contain a significant amount of carbonate hardness (KH), which boosts the pH of "low pH sea salts". When you start using the Tap Water Filter, you might need to use a pH buffering product to raise the KH of the saltwater and increase the pH.

Manufacturer Info

Aquarium Pharmaceuticals Aquarium Supplies
Aquarium Pharmaceuticals (API) has been helping people take good care of ornamental fish for over 40 years. Their research and development scientists have advanced the care of fish with all-natural medications, stable bacteria for biological filtration, one-bottle test kits, consumer-friendly dosing caps and much more. They’ve received over 25 global patents for their breakthrough innovations in the aquatics industry. And they continue to look for ways to improve the fishkeeping experience for hobbyists. Research. Experience. Dedication to scientific, quality treatment for healthy fish. It’s what makes API the first choice of aquarium owners. API manufactures and sells hundreds of products across many different product categories, including aquarium and pond treatments, aquarium equipment, aquariums and fish nutrition.


No warranty

34 Reviews



Experience Level: Intermediate


This has saves me so much time & money. I don't have to pay for the DI water nor the gas To get to my LFS that is 20+ miles away. It is so easy to use however it does take a good while to fill my new 55 gal tank. I really don't mind that as it has already paid for itself between filling the new one & doing water exchanges with existing 2 tanks. Thank you so much, Debbie

Was this review helpful?



Experience Level: Intermediate


easy to use, compact, light weight, excellent product.

0 out of 2 found this review helpful

Was this review helpful?



Experience Level: Intermediate

great product

This deionizer filter has made a great improvement on my reef tank and my soft water tetra tank. Nitrates and phosphates are way lower. my Corals are not suffering from tap water anymore. My water smells clean and no more hare algae. The filter is cheap and changes color when it uses up. It is very easy to use. I recommend this filter for small tanks because it uses up fast, but it does the job.

Was this review helpful?



Experience Level: Intermediate

Great Filter

I was very cautious about this unit, but this was a great, affordable buy. I have used this for over a year and it has produced great water, have not lost a fish since I started this hobby, I attribute it to starting with the right water and this filter delivers. I also think you have to start with good public water coupled with the API Tap Water Filter.

2 out of 2 found this review helpful

Was this review helpful?



Experience Level: Intermediate

cleaning up tap water

Easy to hook up to kitchen faucet. It is doing what promised - giving water I can feel good about putting in my fish tank

Was this review helpful?



Experience Level: Expert

Makes perfect water, BUT

only makes 20 gallons per filter cartridge. If you have hard water this will not last long. Do your self a favor and get a RO/DI unit. You can replace 1 year worth of cartridges on a ro unit for the price of 1 filter for this

3 out of 3 found this review helpful

Was this review helpful?

Dutch from Santa Maria, CA UNITED STATES


Experience Level: Intermediate

Impurities Zapped

This tap water filter works. Living in a farming community sometimes the tap water has higher levels of chemicals. The filter removes them all as advertised. I save money by not having to go and buy DI water from the store. That being said, my water changes are small, usually 2 gallons every ten days. I am using Red Sea Coral Pro salt thar mixes nicely with the filtered water. I would invest in a bigger filtration system if my water changes were significant. Four stars only because the universal connector for the faucet doesn't quite fit, and the unit does leak a little. Overall, saving money and time, which are my two most valuable resources! Setup: 29 gallon reef only tank

0 out of 4 found this review helpful

Was this review helpful?



Experience Level: Beginner

Not bad

Not bad so far. It's a cheap and ideal investment. Only problem I have is that the "universal" fittings don't fit my kitchen faucet, so the bathroom is what I'm limited to. Could be I just have an odd ball faucet...

Was this review helpful?



Experience Level: Intermediate

Great Product for reefs!

I had this filter for 3 years and used it for my weekly water changes in my 55 gallon reef aquarium and I never once had a issue ever it produces great quailty water for any aquarium including reef tanks. I did 5 gallon water changes with it, I did sell mine after I got rid of my tank but just bought it again for my 28 gallon JBJ nano cube LED tank because it is such a great product. Obvisely if you have a huge tank I wouldnt reccomend it but I used it for my 55 and worked great!

8 out of 9 found this review helpful

Was this review helpful?



Experience Level: Intermediate

api tap water filter

Tap water filter did everything as advertised. Produced very pure aquarium water and was extremley easy to use. Wish I had this product years ago when fighting over amounts of algae feeding nutrients from well water.

5 out of 5 found this review helpful

Was this review helpful?

Accessories for Aquarium Pharmaceuticals Tap Water Filter

Similar Items