ROWAphos & Phosphate-Test

Questions about ROWAphos & Phosphate Test

How does ROWAphos actually work?


ROWAphos is an adsorbent material based on iron hydroxide. It consists of iron oxide hydrate (FeOOH) and water. ROWAphos is made from synthetic fabrics of high purity. It binds (adsorbs) phosphates and silicates, which it does not allow to dissolve again. Unlike some other phosphate removers, ROWAphos does not have a negative effect on the pool water. It can therefore also be used for sensitive fish and lower animals in freshwater and saltwater aquariums.

ROWAphos is also used in drinking water treatment because, in addition to phosphate and silicate, it also removes arsenic extremely effectively. Thanks to our material, compliance with the strict arsenic limit values for drinking water in Germany is possible in many waterworks. 


Use of ROWAphos in the fluidized bed reactor


How do I use ROWAphos in a fluidized bed reactor?


ROWAphos is being used more and more frequently in the fluidized bed reactor. The advantage is obvious: due to the very good contact of the granules with the seawater, the adsorption capacity is improved even further.

You can find out the best way to set it and other tips in this YouTube video by The LAB: ROWAphos and how it works.

How often do I need to replace ROWAphos? When is the material exhausted?


In general, no general information can be given on the service life of the filter material since the service life depends on the phosphate content of the respective basin. The phosphate content in the basin does not only depend on the concentration of the basin water. Often, for example, a lot of phosphate was stored in the substrate and in the decoration due to precipitation reactions. This phosphate slowly dissolves again and can lead to a significant increase in the phosphate concentration in the pool water.

ROWAphos binds the phosphate dissolved in the water quickly and extremely efficiently. The decrease in phosphate concentration is easily traceable and measurable with a good drop test. When the material is exhausted, i.e., no more phosphate can be bound, the concentration slowly rises again. This increase is caused exclusively by the formation of new phosphates (e.g., by the demineralization of organic matter) and by bound phosphate. ROWAphos produces no more phosphate.As soon as you measure an increase in phosphate concentration, ROWAphos must be replaced.

Many commercially available phosphate tests are only of limited significance at low concentrations, especially in the seawater sector. We therefore recommend using a test that provides reliable and reproducible results, especially at the low phosphate concentrations required in seawater aquariums.

Problems with diatoms - Silicate


Unfortunately, after removing all bottom-living algae eaters, I have problems with diatoms. Even the use of hardened osmosis water only helps to a limited extent in my 140-liter freshwater aquarium. It is clear to me that there are a number of other parameters that affect the growth of algae.

1. Why am I not allowed to rinse ROWAphos before insertion? Unfortunately, I did, albeit briefly.

2. The manual says nothing more about the SiO2 binding. To what extent is SiO2 bound?

3. Can I safely leave the phosphate absorber in the filter? Is there a residual amount of phosphate left in the aquarium that is needed by the plants?

Thank you very much for your responses and greetings.

PS: In the pet store, I was alerted to the problem of polyphosphates in drinking water. What is the significance of this connection in drinking water treatment, and what are the consequences for aquaristics?


Unfortunately, silicate is not as well retained by reverse osmosis systems as other substances. On average, about 20–30% of them pass through the membrane and are found in the permeate. Depending on the initial concentration in the raw water, this can lead to problems. That seems to be the case with you.

For your questions:
No problem rinsing out ROWAphos.We used to have customers who poured the material into a kitchen colander and then complained that there was nothing left. Careful rinsing is completely fine.

We do not specify capacities because they always depend on the initial concentrations, flow conditions, contact times, phosphate content, etc. and are therefore different in each basin.

Our marine aquarists always run their tanks permanently without any problems with ROWAphos. In fresh water, it depends. As a rule, we also recommend continuous use here. Of course, if you have a pool with a lot of plants, they need a little phosphate to grow. However, due to mineralization and the addition of feed, they have a constant phosphate input. You should measure the phosphate concentration regularly and not overdose on ROWAphos.

Polyphosphates and silicates are used by the waterworks to protect the pipeline network. They are very well retained by the RO membranes. Biologically, the polyphosphates in the drinking water are not available for the time being. They must first be broken down into orthophosphate and then enter the cells via transport systems (our energy storage at the cellular level also takes place via polyphosphates!).

Phosphate Test Scale


I have a Rowa phosphate test. 
In this test, two values are displayed on the scale. Is it correct that the first row of scales does NOT show the phosphate value usual in aquatic organisms, but the second row does?

How can I interpret the measurement result correctly if I want to determine the PO4 value of the water sample?


As you correctly assumed, the bottom line shows the phosphate value. The upper line, the lower value, indicates the phosphorus content of the phosphate compounds in the water.

The free (= ortho-) phosphate is determined by the test. The phosphorus content of the phosphate compounds (PO4-P) is then determined via a conversion factor.

So you can read the phosphate content directly on the bottom line.

Does ROWAphos work like an ion exchanger?


Your review of the new ROWAphos convinced me; I will opt for this product. I was very skeptical because I maintain a large disco pool.  

You mention that your preparation must be kept "moist." I assume that this is the same principle as "ion exchange resins," that is, it emits a substance in order to be able to bind phosphate and silicate? What kind of fabric is this in this case? Thank you very much for your message.  


No, ROWAphos does not work like an ion exchanger. In the case of an ion exchanger, the process is just "exchanged." ROWAphos adsorbs, i.e., binds, the phosphate without exchanging it for anything and does not release it again.  

In the case of an ion exchanger, the bound ions can dissolve again when all the "binding sites" are occupied.  In the worst case, such a filter "breaks through," i.e., more of the substance to be removed gets back into the water than was originally contained in the water. This does not happen at ROWAphos.

Refill pack phosphate test


Where can I get the refill pack for the Rowa phosphate test item no. 1.20066.0001?


Unfortunately, the refill pack is no longer available.

Replacement tubes for phosphate test


Unfortunately, one of the glass tubes fell off from your phosphate test. I didn't want to buy a new one because the test had barely been used. Can the glass also be purchased individually?


Please contact a pharmacy or a laboratory dealer. You can get a corresponding tube there. The order number of the tube can be found on the instruction manual.

ROWAphos completely moist


I wanted to exchange my ROWAphos today. However, when I opened the package, it was completely damp due to condensation. The package was left unused in the closet for about 3 months. Can I still use the phosphate adsorber, or should I buy a new one?


ROWAphos is always damp and must also be stored in a damp place. If it dries out, you can still use it, but the capacity (i.e., the amount of phosphate that is bound) decreases.

So, don't worry, it's all right.