# RO Filtration



## pkillur (May 24, 2006)

I have a question for the non-newbies out there. I'm interested in getting into the dwarven Cichlid and Discus species tanks, but apparently they're quite finicky about their water purity. Does anyone use a Reverse Osmosis (RO) water filter for their tanks at all? The questions I have are the following:

1: Can they be automated to run a couple of times a week for a set period, or are they just "dumb" appliances?

2: How long do the cartridges last?

3: Is there a good place to buy a used RO setup (I'm thinking about joining the SVAS, perhaps they might have something...)

4: Can a regular RO setup from some place like Costco be employed or do they need to be specifically suited for fish?


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## violet (Mar 17, 2006)

There are devices to top off tanks or water storage tanks, uses a float valve, I don't use anything like that.

The amount of time a cartridge lasts depends on how pure your water is and how much water you run through them. They cost nothing compared to the membrane.

I use a 1 micron particle filter as the first stage, then a carbon block as the second. I rarely use the DI stage so I only hook it up as needed. Lastly is the actual RO membrane. 

I bought mine (a Kent) on eBay. It was a steal.

There are multiple stages to RO units. Any unit which has them all, in separate housings should be fine.

Many people chose to add deionizing for REALLY pure water. Household units will not have that, drinking water is not deionized. It makes it taste funny, flat. If you don't want to deionize a household unit would be fine. People who want to make their water from *scratch* do both RO/DI to get the TDS down REALLY low. It is almost as pure as distilled if the cartridges are maintained.

Get a flush kit to prolong the life of the membrane. I paid 30% more for a new membrane than I did the WHOLE working RO/DI unit.

Consider that there is a lot of waste water produced for every gallon of RO. Try and find something to do with it. Water the veggies, top off the outdoor pond, anything. Keeping track of how many gallons of water are USED to produce a gallon of RO tells a lot about how your system is working. As the ration worsens you know the membrane is clogging and needs to be flushed well (which you should be doing anyways) or replaced.

The so called *waste* has been filtered for particles and been through carbon. It is a lot better quality water than came from the tap. I use it for some tanks which have inhabitants which are okay with less than lab grade water (which is most). I probably use as much RO water for drinking water as I do for aquatics.

now I am thirsty,
violet


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## craftyflalady (Jan 25, 2006)

Wow Violet! Thanks for the great post. RO 101 in laymans terms! Alot of information there. Really appreciated by this fish keeper who knows nothing about RO, but I know more now then I did! 

Thanks again,
Kathy


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## pkillur (May 24, 2006)

violet said:


> There are devices to top off tanks or water storage tanks, uses a float valve, I don't use anything like that.
> 
> The amount of time a cartridge lasts depends on how pure your water is and how much water you run through them. They cost nothing compared to the membrane.
> 
> ...


So, basically, you have to have a little tank for this thing to spit out both RO'd water and the "bad" water? How big does it need to be?


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## Fishfirst (Jan 24, 2005)

we use garbage cans hooked together with pipe and a silicone seal. the waste water we actually waste at the store, putting it down the drain, you would probably need a lot more garbage cans for waste water than the RO


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## violet (Mar 17, 2006)

You're welcome Kathy, I read page after page of scientific mumbo jumbo only to discover, once I got one, it's a fancy water filter.

I flush my membrane more than is required and replace the cartridges regularly. For each gallon of RO water, I *waste* roughly 4 gallons which is pretty good. I have a big barrel for waste and a big bucket for RO. I always do it as late at night as possible (water pressure is higher). The bucket is small enough to warm up naturally to use the next day, the barrel I toss a heater into.

Thirsty again,
violet


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## AndrewH (Mar 17, 2005)

I'm planning on setting up a line of filters (the 1 micro, and two carbon blocks) and have it directly dump into my tank (just no RO membrane and all the equipment needed for the higher PSI), and then have a gravity drain, running all the time (but set really slow).

If you wanted to have an RO unit setup basically the same way, you could use a water valve on a timer (kinda like a water sprinkler setup, but not as fansy and should be somewhat cheap). This way you could set the time when the RO will run and when it will shut off (most under sink RO units are plumbed so that the *waste* water just goes down the sink drain).


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