SeaChem Hypersorb/Renew vs. Carbon filter in RODI Unit?

[ichthyogeek]

I was looking up various SeaChem products because why not, and came across HyperSorb and Renew. If they're being touted as an adsorbent like carbon....is it possible to just replace the carbon prefilter with HyperSorb/Renew in an RO/DI unit and then regenerate as necessary to minimize costs? Or am I missing something important? Is it too much work? Would you be able to pack it in like DI resin?

BRS 2.5"x10" standard cartridge Volume = 49.09 inches cubed =804 cm cubed ~= 804mL
804 mL * 75 gallons/250mL = 241.2 gallons that can be treated

BRS 75 GPD at 3:1 rejection rate = 300 gpd total (75 * 3 = 225 gallons rejected, + 75 gallons accepted)

So each cartridge would have to be replaced every (241.2 gallons/300gpd =.804 days = )19.264 hours and soaked in a bleach solution.

 

[Randy Holmes-Farley]

No!!!

These do a similar thing to activated carbon in terms of binding organic matter from aquarium water. They will not break down chlorine and chloramine, which is the purpose in an RO/DI.

 

[ichthyogeek]

Well darn! I thought they'd also adsorb/break down the chlorine products but if not then oh well. Thanks Randy!

 

[Randy Holmes-Farley]

Well darn! I thought they'd also adsorb/break down the chlorine products but if not then oh well. Thanks Randy!

The binding of organics and the catalytic breakdown of chlorine are very different chemical properties.

 

[ichthyogeek]

That's true! I guess it doesn't have the "advantage" of breaking down chlorine then. Now...time to figure out how carbon does that to chlorine....

Seachem - HyperSorb

www.seachem.com

 

[Randy Holmes-Farley]

That's true! I guess it doesn't have the "advantage" of breaking down chlorine then. Now...time to figure out how carbon does that to chlorine....

Seachem - HyperSorb

www.seachem.com

I show that here:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com

from it:


Carbon Filters

The next filter in line typically contains activated carbon. The primary purpose of this activated carbon is to break down the chlorine and chloramine in the tap water (Figure 2). If not removed, these compounds may damage the RO membrane. They will also pass through the remaining filters (RO and DI) fairly readily, and so can end up in the final filtered water.


The reactions within the activated carbon that break down these compounds rely on having enough active surface area for these catalytic reactions to take place. If the sediment filter is faulty, sediment may clog the activated carbon and reduce its ability to break the compounds down. Chlorine and its hydration product in water, hypochlorite ion (ClO-), are broken down into chloride ion (Cl-) and oxygen as shown in reactions 1 and 2 below. Equation 1 occurs at the water supply site where the water is chlorinated, and equation 2 takes place on the activated carbon in the RO/DI filter (where C* stands for the activated carbon and CO* stands for the activated carbon with an attached oxygen atom).

(1) Cl2 + H2O --> OCl- + 2H+ + Cl-
(2) ClO- + C* --> Cl- + CO*

Some of the oxidized activated carbon remains, and some breaks down to produce oxygen (O2):

(3) 2CO* --> 2C* + O2

None of the products of reactions 2 or 3 is of concern to reef aquarists.

The reaction of chloramine (NH2Cl) on activated carbon is a bit more complicated, and produces ammonia (NH3), chloride (Cl-), and nitrogen gas (N2). Equations 4 and 5 show the processes.

(4) NH2Cl + H2O + C* --> NH3 + Cl- + H+ + CO*
(5) 2NH2Cl + CO* --> N2 + H2O+ 2H+ + 2Cl- + C*

Unlike the breakdown of chlorine, one of the byproducts of chloramine breakdown, specifically ammonia, is of significant concern to reef aquarists. Ammonia will pass fairly readily through an RO membrane (discussed later in this article), but if there is a DI system, it should effectively remove ammonia.

The carbon filters used in an RO/DI system will also remove certain organic chemicals from the water. Most of these are large enough not to pass through the RO membrane, but a few may be small enough to get through, yet still be reasonably well bound by the carbon. An example of something bound by the carbon that might otherwise get through the RO membrane is trichloromethane (CHCl3). In general, however, I do not believe that this binding is important for reef aquarium applications using normal potable water as the source.

Often the carbon filter also acts as a secondary sediment filter, and can therefore become clogged over time. A pressure drop at the RO membrane that is not solved by replacing the sediment filter may be due to a clogged carbon filter. In some cases, clogged filters may be cleared somewhat by backwashing, if the system permits reverse flow. Both carbon and sediment filters can become clogged with bacteria as well. In such a situation, some aquarists dry the filters out, thereby opening the pores, and then reusing them. I have never backwashed or dried any of my filters.