RO System for 360 gal tank

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zoobug

Aquarium Advice Apprentice
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Nov 16, 2014
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Hi all - I'm doing a 360 gal setup - I plan to use some RO water for my discus and thought it might be helpful to install in the stand underneath - any ideas? Or is it better to put in the utility closet and fill up a tank to use when I need it. The one I am looking at purchasing is a Neptune 200 GPD unit and has a float valve - would that go into the tank itself? I appreciate any advice - I have never used RO water but always used driftwood, peat in the filtration system and that has worked for my smaller tanks and kept my discus happy. I'm finishing the space around the basement and thought if I want it there then now is the time to put it in. Thanks in advance for any help!
 
What I do is have the RODI unit fill a holding container, in my case 2 55g drums. I then pump the water from there into the tank during water changes. The storage container holds the float valve(s).

You will probably need to pre-treat the water before adding or at least add some additives while you are adding the new water so you probably don't want a continuous drip system straight into the tank.

You should consider that the largest water change you can perform will be equal to the size of your holding container less ~10% since you need room for the float valve. I have a 200g tank and the 110g of storage is sometimes less than I would like.
 
Hi all - I'm doing a 360 gal setup - I plan to use some RO water for my discus and thought it might be helpful to install in the stand underneath - any ideas? Or is it better to put in the utility closet and fill up a tank to use when I need it. The one I am looking at purchasing is a Neptune 200 GPD unit and has a float valve - would that go into the tank itself? I appreciate any advice - I have never used RO water but always used driftwood, peat in the filtration system and that has worked for my smaller tanks and kept my discus happy. I'm finishing the space around the basement and thought if I want it there then now is the time to put it in. Thanks in advance for any help!

Hello, good luck!
How long have you kept fish?

(You will need a TDS meter.
Follow the pre clean instructions for the CCB and floss block thoroughly as a mistake could compromise the RO membrane. The membranes are sensitive to chlorine. Do not flush with water that hasn't past through the CCB.

It's easiest to have the unit at or near a sink, this will help at filter change times, normally it's around 6 or 12 months depending. Some water is spilt at this time.

After years of use mine is now above the sink. If the water is cold they condensate something rotten. I think it's better with the water close to the tank as it negates pumps and plumbing.

For the amount of water you will need, a proper container would be useful!
360G is a lot of water. 1600L I don't manage that much water over all my systems and storing RO is a big deal for me!
72g is 20% (average normal change) and as I understand it, it's little and often for discus.

I struggle with a 200 litre storage tank and 4x25 litre containers.
I'll just about have 1600 litres once I fill my reef!

Your water would be more simple if it's just for one tank, mine is complicated.

I think the cheapest way to treat that volume is to re mineralise pure RO using Gh Kh powders. You will need relevant test kits.
I measure powder by weight. You need to be quite accurate.
I used to cut RO with de chlorinated treated tap water but it's expensive long term on large volumes.

The float valve probably closes off production when storage tank is full.
Water needs mixing a bit before you use it in the display tank or a dosing system could be used if you operate a full time overflow. Direct use of RO in a tank is for serious use only, I don't advise on it but it is possible)

(y)
 
Thanks guys this clears things up lots. I've been keeping fish for about 30 years - just didn't ever go this big. I have also always used our local water and done great with my discus. I've always used a python system straight from tap and it has worked well. Maybe I'll just stick with that.:)
 
I think the best thing you could do is to automate the whole thing. Water changes for this volume can be a real pain. And since you are setting up a RO unit, this means you have access connect stuff to your house's drain and tap water.

So, if your tank has a pierced overflow, you can connect it directly to the drain. Then doing a water change is a simple matter of getting new water into the tank, and excess water from the tank will go down the drain. The water change is activated by a timer that opens a solenoid valve which allows water into the RO unit and then to the tank. The float switch you have will simply be a safety to stop it in case something goes wrong, to make sure the tank doesn't overfill and spill on the floor.

But you need to add some GH with that new water. You could prepare some water mixed with GH powder in a 18L bottle, and have a dosing pump controled by a timer add it to the tank at the same time as the water changes. For example, you prepare that concentrated GH water so 1ml of it added to 1L of RO water gives it the parameters you want. So you only need to have the GH timer activate long enough to dose what is needed for the amount of water that gets changed by your water change's timer.

I have a similar setup on my 95g. Except I don't use the RO membrane (only sediment and carbon to remove chlorine) because I don't need soft water, and the 18L bottles are for dosing fertilizers which I prepare for 4 months at a time. It is so wonderful to have an aquarium that mostly takes care of itself!
 
Unless you are OK with a pH in the high 4's you would also need to dose something to increase KH.
 
I think the best thing you could do is to automate the whole thing. Water changes for this volume can be a real pain. And since you are setting up a RO unit, this means you have access connect stuff to your house's drain and tap water.

So, if your tank has a pierced overflow, you can connect it directly to the drain. Then doing a water change is a simple matter of getting new water into the tank, and excess water from the tank will go down the drain. The water change is activated by a timer that opens a solenoid valve which allows water into the RO unit and then to the tank. The float switch you have will simply be a safety to stop it in case something goes wrong, to make sure the tank doesn't overfill and spill on the floor.

But you need to add some GH with that new water. You could prepare some water mixed with GH powder in a 18L bottle, and have a dosing pump controled by a timer add it to the tank at the same time as the water changes. For example, you prepare that concentrated GH water so 1ml of it added to 1L of RO water gives it the parameters you want. So you only need to have the GH timer activate long enough to dose what is needed for the amount of water that gets changed by your water change's timer.

I have a similar setup on my 95g. Except I don't use the RO membrane (only sediment and carbon to remove chlorine) because I don't need soft water, and the 18L bottles are for dosing fertilizers which I prepare for 4 months at a time. It is so wonderful to have an aquarium that mostly takes care of itself!


Unfortunately it is not near a drain or this sounds like it would be a fantastic setup - I would have to cut about 15 ft of concrete to tie into the closest drain - I wish I had better planning beforehand!:(
 
Since you said "I plan to use some RO water for my discus and thought it might be helpful to install in the stand underneath" I assumed the drain was somewhere near... or how did you plan to deal with the reject water from the RO unit?
 
Why would it go so low?
Because RODI water has 0 KH. So it will have an arbitrary pH value when you start but will quickly crash in the tank in the presence of biologicals. In my experience, once pH crashes in an aquarium environment it ends up in the high 4's. Honestly, I don't have the chemistry background to understand why it always seems to end up there. Now, I have kept tanks with some fish from extremely acidic conditions successfully in waters in such a scenario but you would want to do that on purpose not have it happen as an accident.
 
Since you said "I plan to use some RO water for my discus and thought it might be helpful to install in the stand underneath" I assumed the drain was somewhere near... or how did you plan to deal with the reject water from the RO unit?

Great question! Sorry for the confusion. I thought the water came right from the RO unit and that was it. I realize this is making me sound as stupid as I really am on this subject. :banghead:
 
I'm also hoping that I won't need to do as much water changing due to the size of the tank? It seems that the water in my tanks has been more stable the larger I've gone. Obviously it depends on stock and filtration but would others out there say that this tends to be the case?
 
Great question! Sorry for the confusion. I thought the water came right from the RO unit and that was it. I realize this is making me sound as stupid as I really am on this subject. :banghead:

Don't beat yourself up! We all gotta start somewhere!

Let's face it, you're not the only one!

Alkalinity,
Kh (alkalinity) is the waters ability to resist or neutralise acid, the more Kh you have the more resistance there is, to the point of turning the water base alkaline. That's quite simple but that's basically it. I think the RO water acidifies as it reacts with the Co2 in the atmosphere, it has no Kh and therefor no ability to resist acid. In a tank environment other acidifying factors come into play, decomposition for example.

GH is your hardness, this is simple the more you have the harder your water is.

RO water is cleared of almost everything, 0 GH/Kh, DI resin purifies it further, this is at the molecular level (ion exchange resin). This takes out all of the final impurities and leaves an even balance of H+ and OH ions. So you initially test neutral pH and 000TDS.

I'm also hoping that I won't need to do as much water changing due to the size of the tank? It seems that the water in my tanks has been more stable the larger I've gone. Obviously it depends on stock and filtration but would others out there say that this tends to be the case?

It's relative I'm afraid! E.g. 20% is still 20%!
Bigger fish need more care, the water stays good for a bit longer but to return it to normal takes longer too! Really it's the same just on a larger scale unless you are severely under stocked or you don't feed enough as a control.

If and when you get this tank it will be awe inspiring!
(So post a pic!)

(Edit)

With an RO unit you have a mains water inlet, just before the membrane this Ts off, one side goes through the RO membrane and one side goes to waste or is re routed through a second membrane. The other side of the membrane is your output or production water.

RO unit,
https://www.flickr.com/photos/92891884@N04/10255257976/ (red in, blue waste, green production)

Schematic (left corner is standard)

https://www.flickr.com/photos/92891884@N04/13455394703/
 
This is great stuff thanks for taking the time it's much appreciated!


Sent from my iPhone using Aquarium Advice
 
No worries, thanks for the thanks!
When I started keeping fish all I knew was that I wanted fish.
All I knew about water was that it came in two types, hot and cold!

(It is quite complex to begin with but it really is quite simple after a year of use)
 
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