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Ashton

First time reef keeping in Austin. Looking for RODI system recommendations

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Hi everyone. I'm finally getting everything I need for my new 15 gallon and I'm having trouble figuring out which RODI system to get. I'm currently using City Of Austin water and am not sure even how many stages I should go with.

 

Will a 4 stage system be enough or do I need to go with something larger?

 

Thanks for any input y'all have 

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Welcome. The # of stages isn't super relevant, but what is important is what you do with those stages. The key piece for CoA water is that we use chloramines. That means that any old carbon block wont do. Once chloramines break through the carbon block, they degrade the RO membrane and quickly deplete your DI resin. 

Check this video out for more info:
 

The minimum I'd recommend you run is prefilter->universal carbon block->RO membrane->DI Resin. So that would be 5 stages *at a minimum*. I run redundant carbon and redundant DI resin  (i.e., 2 carbons, 2 DI resins) and then swap in new cartridges in the last position and move the older cartridge up a position. For example I have OldCarbon1, OldCarbon2. Old Carbon2 becomes NewCarbon1 and NewCarbon2 is a totally new carbon block. I do the same with DI resin. Hope this helps. 

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On 12/26/2018 at 11:59 AM, victoly said:

Welcome. The # of stages isn't super relevant, but what is important is what you do with those stages. The key piece for CoA water is that we use chloramines. That means that any old carbon block wont do. Once chloramines break through the carbon block, they degrade the RO membrane and quickly deplete your DI resin. 

Check this video out for more info:
 

The minimum I'd recommend you run is prefilter->universal carbon block->RO membrane->DI Resin. So that would be 5 stages *at a minimum*. I run redundant carbon and redundant DI resin  (i.e., 2 carbons, 2 DI resins) and then swap in new cartridges in the last position and move the older cartridge up a position. For example I have OldCarbon1, OldCarbon2. Old Carbon2 becomes NewCarbon1 and NewCarbon2 is a totally new carbon block. I do the same with DI resin. Hope this helps. 

Thanks for the extremely useful information.

 

Any advice on how I should go about testing water to determine when I need to switch filters? Sorry, in the past I was blessed with incredibly clean well water so I have no experience dealing with chloramines or other city water contaminants.

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You can use chlorine test strips every so often to test break through after your carbon filter. They have a recommended total flow range, so just calculate the total flow and start testing when you get to maybe 75% of the flow ? Remember that produced water is only a fraction of the total water that goes through the carbon filter. I think most membranes reject 3:1 for produced water.

So for every gallon of produced water, three gallons are rejected. You calculate your total flow through carbon on 4 gallons total flow instead of 1 gallon of produced water.


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When calculating the life expectancy of the GAC filter cartridges it's best to periodicly measure the actual ratio of "waste water" to filtrate.  Not all RO membranes are the same and water pressure can vary by a surprising amount so the amount of rejected water to filtered water can be much higher than 3:1.

 

In my maintenance business I use 3 stage RO, 5 stage RO/DI and just plain tapwater treated with dechlorinator (Ammo Detox) and haven't seen any difference.   When troubleshooting reef problems old filters are often pointed to as a cause and they may be if they are letting chlorine get into the system but in my experience maintaining systems with tapwater I would look someplace else for the problem.  Here's the two systems I've been maintaining with tapwater treated with dechlorinator:

 

 

And here's a system maintained with a water softener then GAC filters (no dechlorinator):

 

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5 hours ago, Timfish said:

In my maintenance business I use 3 stage RO, 5 stage RO/DI and just plain tapwater treated with dechlorinator (Ammo Detox) and haven't seen any difference...

 

Thanks for the insight.  Those are gorgeous!  Maybe I'm misunderstanding, but are you saying for some of your tanks you don't even use a filtration system, you just use COA tap water treated with Ammo Detox? Or are you saying you treat the water first and then run it through a RO/DI filter?

I'm going to be running a 15gallon so obviously I need to be careful with water quality as I don't have a large water volume to work with, but I'm happy to hear any suggestions that may save money in the long term if I don't necessarily need large expensive filtration systems.

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No, you didn't misunderstand me.  I maintain the first two systems in my post with just tapwater and dechlorinator (Austin has pretty decent tapwater).  No RO or RO/DI filter is used.  (No skimmer, dosers, reactors or refugiums either.)   New saltwater is made up at the time of water change and allowed to sit however long it takes to siphon out some water.   

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1 hour ago, Timfish said:

No, you didn't misunderstand me.  I maintain the first two systems in my post with just tapwater and dechlorinator (Austin has pretty decent tapwater).  No RO or RO/DI filter is used.  (No skimmer, dosers, reactors or refugiums either.)   New saltwater is made up at the time of water change and allowed to sit however long it takes to siphon out some water.   

Think I could realistically do this starting from scratch, or would you still recommend I get some sort of RO/DI filtration even if it's minimal?

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Not to counter Timfish's experience and knowledge, I'd personally be more comfortable starting off with DI water from a fish store to start up your 15 gallon reef and build some experience in reefing before either purchasing an expensive RO/DI system or booting up with dechlorinated ATX water. FWIW, I'm slowly adopting some of Timfish's advice like pulling my skimmer and not running a fuge. Not there yet on the water...

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