Reverse Osmosis Filter in a tank?

So after doing some research on Reverse Osmosis Filters I started to wonder how and if it is even possible to set up an R/O Filter in an aquarium tank.
I have no where else to store water so my 30 gallon tank that is already set up, is the only place I can setup the filter.
When I say I have no where else to store it, I mean I have no space, I live in an apartment so this is my only option.

I will need about 10 gallons a week for my 50 gallon Aquarium and I was wondering how I would set it up. I know they come with instructions but most R/O Filters are attached to water lines. My idea was to simply fill my 30 gallon tank as I drained a portion every week and just have the filter keep filtering the water in the 30g.

This was before I did a lot of my research so now I don't know if this is even a good idea. When I read that the filters produce 75 GPD I thought the water had to be filtered a long time to be Pure but now I see these Sink RO Filters that basically RO Filter the water in seconds (I think)

Can someone please help me, I really need this for my water as my Tap Water has some really bad chemistry and getting water from somewhere else would be a hassle.

 

To answer your question with a question, why do you need an R/O system?

Most freshwater aquarists that use RO water have finicky fish or extremely poor tap water quality. If neither of those describe your situation, I would avoid it. The trouble with R/O water (and some may debate this), is that it not only takes out the bad, but also takes out some of the beneficial minerals that certain plants (not sure if you have a planted tank) and fish benefit from. Many who use R/O water find themselves adding supplements to "restore" the water to something naturally occurring.


edit: Very sorry. For someone reason I missed the last part that stated you had really bad tap? What about your tap is bad though?

 

Well my tap water has a very high pH of about 8.4 and always seems to have 0.25ppm Ammonia.
The Carbonate and General Hardness is about 12-14 and I do have a planted aquarium.

I tried using Peat to lower pH in my 30 gallon tank but that didn't help at all but make my aquarium all dirty looking. Driftwood has not helped either.

I have mollies, danios, and a german blue ram in my 50 gallon tank and I have lost several mollies already as well as one danio recently and I want to say it is because of my Tap Water.

I do weekly water changes but they barely help as the Tap Water has Ammonia and Nitrate of about 20 ppm. This is why I want to get an RO Filter to fix my water problem. I will use an RO Water Conditioner to replenish some of the needed essentials that are removed by the filter.

 

An RO unit is a great investment for planted tanks. However, I'm not sure if you have the right idea of how they work. The filter needs to be within a larger RO unit (which is attached to a water line like you said) to work. Simply pushing water through the filter alone probably would not work.

 

The thing is I have no where to store water but my 30 gallon tank that used to have fish. It is now empty but still running (canister filter)

I also saw in a setup video that you can simple connect them to the faucets to get some RO Water, like a quick temporary set up so I'm wondering if I can just do that to get water weekly.

Like instead of filling up my buckets with tap water, run the water from the faucet into the RO System and instantly get RO Water.

That way I don't need a storage tank, I will just need to attach it to the faucet once every week for water changes, but I'm a bit confused because the filter say 75 GPD, which means 75 gallons per day, right? So will simply attaching it to the faucet instantly get me RO Water? Or does the water need to go through the filtiration system several times to be pure?

 

The water needs to run through the unit before becoming pure. If you just want to store it in an empty tank that should be fine. Keep in mind there will be a waste water line that you'll need to find a place for.

 

But how long does it actually need to run through the system? Because the filters say 75 GPD so I was wondering if I can just hook it up to my sink and basically filter the tap water through the RO Unit to get RO Water right away.

 

The water starts coming out soon after you start the water flow. However the issue is flow rate - it comes out pretty slowly. Hence the 75 GPD - due to the slowness of the flow rate it'll take roughly 24 hours for 75 gallons of pure water to be produced.

 

An RO unit is a great investment for planted tanks. However, I'm not sure if you have the right idea of how they work. The filter needs to be within a larger RO unit (which is attached to a water line like you said) to work. Simply pushing water through the filter alone probably would not work.

Why do you say that RO is a great investment for PLANTED TANKS? RO water is actually not necessarily good for plants as it has none of the minerals like calcium and magnesium that most regular tap water has. Of course you can always remineralize your water to add it back in or a good micro/trace fert mix would cover you. But R/O water isn't needed for plants. It may be something the OP wants to help lower the hardness of his water. As for the ammonia, if you have a moderate amount of plants they should eliminate the ammonia from the new water pretty quickly.

As for the OP's question about setup. You could setup some sort of system with a float that shuts off the water flow when the tank is full. Then you would use the water and it would fill back up slowly over the next day. All of this would be a bit expensive and a bit much in my opinion. I wouldn't invest in an RO system if I was living in a apartment and space were an issue.

As for your fish issues, mollies, danios, and rams do fine in harder water, so I don't think its the hardness that is affecting them. The ammonia could be. Nitrate of 20 would not affect them, as anything below 40ish is fine for most fish. So that boils it down to the ammonia, or maybe you just got some bad fish. Many fish, like people, end up coming down with something from the petstore, genetics, stress of being transferred to a new tank, water changes etc. If you think its the ammonia you could just be sure to treat with Prime to neutralize the ammonia until the plants could remove it. Or you could do this semI cheaper option.....

Use the 30 gallon tank as a holding tank with no fish in it, juts a ton of easy quick growing plants that will soak up the ammonia and nitrates. Plants that would work include hornwort, anachars, or floaters like frogbit and duckweed. Fill up your 30 gallon tank with tap water. Put a couple of cheap clip on shop lights with some 6500k spiral CFL screw in bulbs on top of the tank. Throw in some of the easy plants and let them do the work for you. After a few days, any ammonia should be consumed, then the water is ready for you to use for water changes. Refill with new tap water and repeat the process. This is the basic concept on a refugium.

 

Well the mollies I currently have were born from a molly I had that passed away.
I'm not sure why there is still ammonia in the aquarium though, my tank has about 25 Jungle Val Clusters, a Java Moss Ball, Java Moss (2.5 inch), and 5 Sword Plants (I forget the specific type) so I would say my aquarium is medium to heavily planted but they are not removing the ammonia.

And also, what would I do to solve the pH issue? The pH is 8.4 which is unacceptable for them as that is a pH for Hard Water Cichlids or Marine Fish. If I don't get a an RO Filter, how can I lower the pH and keep it stable without using additives that instantly change it and then it spikes back up.

 

If the pH never changes from 8.4 then it's not an issue. Your fish will get used to it. Ammonia is the real problem.

I also live in an apartment and installed my 5 stage, 75GPD RO-DI unit under the sink. I even installed a 3.5 gallon pressure tank and is also hooked up to the fridge for water and ice. An RO membrane has 3 ports, an input line from tap and 2 outlets. One outlet for purified water and the other goes down the drain as waste water. For every glass of good water produced, three or four glasses go down the drain as waste water. That means for every gallon of water produced, that translates to four or five gallons on your water bill. Now you see why you can't use an RO filter to filter your tank? Also, the harder your source water the more often you have to change the cartridges. But there's a way to prolong membrane life by installing a flush kit. My tap water line is about 85psi. The higher the line pressure the better performance you will get. My RO-DI filter produces 5 gallons in 1 hour and 6 minutes on a very hot day and 1 hour and 12 minutes on a very cold day. I keep three 5 gallon jugs in the other room for my weekly water changes. I need to buy one more 5 gallon jug but also ran out of space. I have a 60 gallon aquarium by the way.

 

Yea PH shouldn't be an issue. I have neon tetras in my water which is around 8ish and they are supposed to need 6.5 PH.

Also about your plants and ammonia. For one, moderate to heavy planting means that there is hardly any substrate visible, with almost all spots taken up by plants. Second, the plants you listed are good easy plants but maybe not the best for sucking up ammonia/nitrates etc. Java moss is a water column feeder but it's a very slow grower so doesn't absorb a lot of stuff from the water. The Vals and Swords are root feeders so they don't absorb anything from the water, they get their nutrients from detritus and fish poo down in the substrate.

For some good water column feeders that would suck up that ammonia and nitrate, I recommend hornwort, anacharis, frogbit, or even duckweed (although most people, myself included, hate duckweed). Hornwort especially is a nitrate sponge. I have a sales thread in the buy/sell forum and am selling hornwort, frogbit and some other plants if you are interested or need some pics/info on them.

 

Why do you say that RO is a great investment for PLANTED TANKS? RO water is actually not necessarily good for plants as it has none of the minerals like calcium and magnesium that most regular tap water has. Of course you can always remineralize your water to add it back in or a good micro/trace fert mix would cover you. But R/O water isn't needed for plants. It may be something the OP wants to help lower the hardness of his water.

The reason I say RO water is good for planted tanks is that it gives you a lot of control over your tank. Poor tap water can contain substances bad for plants (for example ammonia can cause melting at even 3ppm). It also makes it much easier to pinpoint and remedy any deficiencies you may be seeing, as you know exactly what's in your water.

Of course the water has to be remineralized to a degree. However, many plants actually prefer softer water and are thrive in water with a dgh as low as 2. Many plants actually do substantially better in soft water and some actually struggle in hard water. Furthermore, soft water helps prevent excessive algal growth, especially of the various filamentous algaes.

Granted, a lot of this mainly applies to high tech tanks with delicate plants, high light, and co2. However, you'll find that many serious planted tankers either use ro or are fortunate to have soft tap water (which op does not). For a simple low maintenance setup with common beginner plants it may not be as helpful (though the algae inhibition is still a great advantage).


For fish, pH is not too important as long as general hardness (gH or dGH depending on how you measure) is in order. What's important here is what kind of fish you want to keep in the long run. Mollies are fine with dGH of 12-14 that you mentioned earlier, and most common danios will be fine in this water also. However, you also mentioned german blue rams, which are soft water fish with an upper GH range of 10 dGH. I also have hard tap water (around 15 dGH) and used to keep soft water fish like cardinals and rams. While they may seem to be thriving, their lifespans are actually shortened by the stresses on their organs (like the kidneys) that processing all the extra minerals causes.

 

Yeah I don't really like duckweed. They block too much light for planted plants, I had some before and didn't like it much.
I can definitely get some hornwort though, I had it before and they are fast growers.

I once order some Java Moss Balls online and got a notice saying they were destroyed because soil was detected so now I'm scared to order more plants online.

My German Blue Ram doesn't look very happy though, one because she is lonely (I only have one currently) and two because the water is not soft. Thank you for clearing up how the RO Filters work though, I had no idea they would produce so much waste water.

The hardness and pH does seem to be stable so if it stays stable then ammonia is the only problem which hopefully hornwort plants will help.

 

Ordering plants online is very easy; just make sure to order from a seller from within the U.S. who ships legally as opposed to an international one who ships illegally (which I suspect was the case with your moss).

 

Perhaps, I will make sure they are from the US next time then, thanks.

 

Another thing Angel needs to realize about the RO systems is that they require high pressure to operate. If you didn't connect it to your tap water system, you'd need an expensive and noisy pump to pressure it up.

And a RO system is "Once Through". It isn't like an aquarium filter that constantly recycles the same water through itself over and over. Instead, think of it as a one-pass system to create very pure water from your tap water.

When you see one feeding a small faucet, what you don't see is the pressure tank that stores up the produced water over time so that you can dispense it when needed. This usually all mounts under your sink, out of sight.

The RO system produces water as a slow trickle. You then store it up as it's produced, for later use.

One other point: You can mix your raw tap water with your RO water to get the hardness you want unless there is some special blend of minerals you need that the tap water doesn't have.