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I already have an RODI unit from when the tank was saltwater. Can I run tap water just through the sediment and carbon blocks and use that water in my tank? That way it would still have all the dissolved solids/minerals but not the chlorine?

Just trying to find a way to work with what I've got... if that won't work I'll go buy a bottle of dechlorinator for a few bucks.
 

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I already have an RODI unit from when the tank was saltwater. Can I run tap water just through the sediment and carbon blocks and use that water in my tank? That way it would still have all the dissolved solids/minerals but not the chlorine?

Just trying to find a way to work with what I've got... if that won't work I'll go buy a bottle of dechlorinator for a few bucks.
That's correct but I would prefer the dechlorinator method because the water coming out of your rodi unit (minus the membrane and di) is too slow for water change. Unless you have to age your water, using something like seachem safe or prime is much easier.
 

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If all you have is chlorine and you have an aging barrel, just run an air stone through it and it's chemical free dechlorination. However, this method doesn't work as well with chloramines.

You might also research cheaper methods (i.e. sodium thiosulfate). When I need dechlor quick though, I usually buy the pond dechlorinators. Higher concentration, but more bang for the buck.

You can also find cheap dechlorinators on aquabid or eBay. Lookup "chlorine remover" or "aquarium conditioner" or something similar.
 

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There is still some controversy over carbon and chloramines. Sellers of carbon say it will remove or remove most chloramines. Testing that shows chloramine removal usually only occurs in systems that use carbon block filters. Bulkreefsupply.com sells a 1 micron carbon block filters that they say removes chloramines. I trust them.

Sodium thiosulfate neutralizes chlorine. It does nothing to remove chloramines or convert chloramines to safe compounds. Aging water in a barrel with an air stone does nothing to chloramines. It will help dissipate chlorine. Almost all municipal water systems use products that cause chloramines. If in doubt, call them. They will tell you whats what and probably offer to send you a copy of the yearly report the EPA requires them to make available.

Prime, Safe (the dry form of Prime), and Chloram-X are the simplest and lowest cost de-chlorinators on the market and they both convert chloramines to ammonium which is safe for your critters and feeds the bacteria in your filter.

The only real issue with Safe or Chloram-X is finding measuring spoons small enough for a five gallon bucket. ;-) The correct dose is 1/40 of a teaspoon. The smallest spoon I've found is 1/32 teaspoon.
 

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Carbon doesn't remove chloramines - it splits it back into chlorine and ammonia. The carbon takes care of the chlorine, and the ammonia flows on downstream where it is treated a bit by the RO, but primarily by DI resin.

If you have chloramines, best to use two carbon stages as contact time is crucial.

Russ
 

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Soooo.... I have a 10 micron prefilter and two carbon blocks, 5 and 1 micron. If I have chloramine I am going to end up with ammonia.

I'll just get some dechlorinator haha.
If you're open to suggestions...

You might want to change the pore size configuration on your prefilters. As is, your carbon blocks are acting as sediment filters.

The whole concept of using prefilters (all filters that touch the water before the RO membrane) with decreasing pore sizes is a good approch, but it applies only to sediment filters.

Carbon blocks should have a pore size about equal to (or larger than) the smallest pore size on any of the sediment filters.

So if you had two sediment filters and one carbon block, this would be good:
10 mic sed
5 mic sed
5 mic carbon

OR

5 mic sed
1 mic sed
1 mic carbon

OR

5 mic sed
1 mic sed
0.5 mic carbon

One other item: Why are you using two carbon blocks? Do you have chloramines?

Russ
 

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That's correct but I would prefer the dechlorinator method because the water coming out of your rodi unit (minus the membrane and di) is too slow for water change. Unless you have to age your water, using something like seachem safe or prime is much easier.
If you're not running it through the membrane, its going to come out at pretty close to the rate it comes out of the tap.
 
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