Hi all,

a friend of mine just gave me 60 liters of RO water. I thought I could wait till the week-end or even later to use it and do some water changes to reduce KH especially.

But,he also told me that I can keep the water for 48 hours at the maximum, beyond, the quality will start decreasing, and he says the RO water will be just good enought to be thrown away after after 3 days.

What do you think?

If you keep it in a container with a tight lid, it should be ok for longer than 3 days.

Your friend would be right if using it for a marine tank. But we can relax that a bit for a shrimp tank. Many people use auto top up systems that will have RO water sitting for more than 48 hours. 

Just make sure no contaminants will get in. \

But try to use it up as soon as you can.

Edited March 15, 201610 yr by jayc

OK
Do I need to remineralize it or can I use it "as is" just for toping or a 10% water change?

7 minutes ago, Matuva said:

OK
Do I need to remineralize it or can I use it "as is" just for toping or a 10% water change?

If you are just topping up water that has been evaporated, then you can use as is - no remineralising.

But if you are doing a water change, then you will want to match the ideal water parameters for your type of shrimp.

OK, thank you for the tips ^^)

@jayc Sorry to jump in... But why is storing RO water more then 48 hours bad for either type of tank? I've run marine tanks and freshwater tanks for years, and not once heard of storing RO (or any water really) for a longer period of time being an issue? 

As long as the container has a tight lid to prevent contaminates getting in, and not in the sun (or bright light) to prevent algae, what would be the problem? I regularly store my RO water for a week at a time in preperation for the next water change ahead of time... Havn't had any issues. 

I also know many people who store RO in large water drums which would last them longer than my 1 week drums.

I think the issue might be with the water going stagnant...I have been told though that as long as it's in an airtight sealed container then it will keep well for a few weeks.  If it's not in an airtight container out of the sun and you want to keep it for a longer period than a couple of days, I've been advised it should be aerated. I keep mine in a 20ltr sealed water drum, out of the sun and it's still fine after a couple of weeks.....

48 minutes ago, s1l3nt said:

But why is storing RO water more then 48 hours bad for either type of tank?

I didn't say it would be bad. Bad is probably not the right term. Maybe "stale" is better.

I know of some friends with Marine tanks that don't like their RO drum going stale. But I don't know if they would go to the extreme of throwing it out.

I personally don't mind. Stale is probably water that has been sitting around too long in a container, and dirt/dust settles on it, oxygen is depleted, and the lack of movement makes it start to smell stale.

Aerating and adding movement will help the RO water from going stale too quickly.

Anyway, what I was trying to say to Matuva is to not worry about it too much as long as the water is kept clean in a container with a lid on it.

Edited March 16, 201610 yr by jayc

20 hours ago, Matuva said:

Hi all,

a friend of mine just gave me 60 liters of RO water. I thought I could wait till the week-end or even later to use it and do some water changes to reduce KH especially.

But,he also told me that I can keep the water for 48 hours at the maximum, beyond, the quality will start decreasing, and he says the RO water will be just good enought to be thrown away after after 3 days.

What do you think?

Hi there,

In regards to the storage of your RO water, have you considered producing your own water to avoid storage? It could be more cost effective to avoid the water going stale.

Thanks for the answers guys, that makes more sense then what I initially read it as :)

On 16/3/2016 at 0:48 PM, Filter Systems Australia said:

Hi there,

In regards to the storage of your RO water, have you considered producing your own water to avoid storage? It could be more cost effective to avoid the water going stale.

Don't you waste a lot of water during the process of reverse osmosis? If I'm not wrong, to produce 1 liter of RO water, you throw away 4 to 5 liters of water?

Edited March 17, 201610 yr by Matuva

1 hour ago, Matuva said:

Don't you waste a lot of water during the process of reverse osmosis

Yes that's true, but if you want RO water then someone will have to produce the waste water so you get the pure clean RO water. If you buy it, like you can in some fish shops, they make you pay for the cost of the water + labour + a small percentage of the filter equipment. 

We collect the waste water to water plants, wash clothes, wash the car, so it's not necessarily a complete waste.

I know many people use waste water for fry grow out tanks, etc. Depending on how bad your water is to begin with. I.e. mine is 80TDS from the tap, waste water is ~120TDS so really not that bad.

Mine also produce about 1-1.5L of waste for every 1L of RO water... FSA systems are great :D

I've also found that my RO filter from FSA produces about 1.5 L of waste water for every litre of RO. I don't have very hard water though. I imagine that is where the 4-5L figure comes from. I use my waste water for washing clothes so it isn't actually wasted. 

6 hours ago, Matuva said:

Don't you waste a lot of water during the process of reverse osmosis? If I'm not wrong, to produce 1 liter of RO water, you throw away 4 to 5 liters of water?

 

1 hour ago, fishmosy said:

I've also found that my RO filter from FSA produces about 1.5 L of waste water for every litre of RO. I don't have very hard water though. I imagine that is where the 4-5L figure comes from. I use my waste water for washing clothes so it isn't actually wasted. 

Hi Guys,

We have designed our systems to produce minimal waste water. Most systems on the market use a filmtech membrane along with a 400cc flow restrictor which will produce a minimum of 1:3 production to waste with near pure inlet water. FSA systems use a CSM membrane and a 200cc restrictor and on average the ratio is about 1:1 but can go as high as 1:2 as you are aware of using the system. One of the good things about producing your own RO water is that you actually get all of the water produced, both waste and 0 tds which you can use for whatever purpose you want.