RO water question

[paudie]

Hi everyone This is my first post just a question about RO units. I bought a 3 stage 50GPD unit for making water for my tanks have not see it up yet I ordered different fitting to connect to the water supply and better fittings for the unit itself I also got an extra filter housing. I was thinking of having an extra carbon filter but not sire if I should be using just RO water or RO/DI. I have only neos at the moment but I  don't trust my tap water and want to get into fancier shrimp in the future once I get another rack up and running. Thanks for any help in advance 

Paudie

 

 

[jayc]

 

Hi Paudie.

An RO/DI unit will always be better than just an RO unit.

Some contaminants do not measure well with a hobbyist grade TDS meter, it takes a conductivity or resistivity meter to measure them. Some of these include phosphates, silicates and nitrates among others. Which means that a TDS meter can show 0 TDS, even if phosphates, silicates and nitrates are present. RO membranes don't deal with this sufficiently. But the DI resin filter will.

So by combining a DI resin filter to the RO membrane, you get the purest water.

I would suggest a DI filter instead of another carbon cartridge, if you can fit it in.

 

Note: when we talk about 'RO' water we usually mean water that has been filtered through an RO/DI filter.

DI filter cartridges expire very quickly. And is usually the first cartridges that needs replacement when you start to see TDS rising from your RO/DI unit.

 

 

Edited January 4, 2016 by jayc

[paudie]

Thanks for letting me know that jayc I'll get one of them before I hook it all up just need to get storage for the water now. I was looking at a 210L water butt for rain water just need to figure out how to stop the water going bad read different things about just put an airstone in it and others say heater and a power head and have no idea how long it will last either thanks again for the help 

[jayc]

12 hours ago, paudie said:

heater and a power head and have no idea how long it will last either

Powerhead and airstones just circulate the water. They just keep RO water from going stale.

A lot RO water users are marine tank owners. They mix the salts into the RO water, so it's ready for a water change when needed. An airstone or powerhead helps dissolve and mix the salts.

When RO water goes 'bad', it means it has been exposed to dust, which carries with it bacteria.

So RO water needs to be kept in a container that is sterile and closed to dust & dirt. RO water kept in a clean, sterile container can last for a while (months).

I wouldn't put a heater in the RO storage container, whoever suggested that has no idea. Bacteria love to breed in warm water! 

That's why we keep food in fridges. If you can fit your RO container in the fridge, it will last agessss !! 

But of course that might be impractical.

Edited January 5, 2016 by jayc

[Ronskitz]

So jayc when you say months is that months with water movement or months in a sealed container with no movement?

[jayc]

13 minutes ago, Ronskitz said:

So jayc when you say months is that months with water movement or months in a sealed container with no movement?

That would be - months in a sealed container, even with no movement. Kept in a cool place (out of the sun).

The moment you add air from say an airstone, you introduce air borne bacteria via dust and dirt. If there is a gap in the lid for the powercord of a powerhead, you are also letting in air that might be carrying bacteria and dust.

If you want to store RO water for periods of months, then it needs to be in a sealed container. As mentioned the container itself also needs to be sterile.

If you know you will use it within the next couple of weeks, then you don't need to be too careful. Any clean container with a lid will do. Personally, I always make RO water on an as needs basis. I don't store it for more than a week.

 

Edited January 5, 2016 by jayc

[Ronskitz]

Ok cool thanks for the promt reply i will sell my 100L container and get 2 smaller ones so iv always got at least one

[ineke]

I'm wondering if you are being a bit over cautious Jayc. I have a 120 litre wheelie bin -food grade- outside under the verandah, I refill it as soon as I have used what I need but rarely empty it completely although i do use close to 100 litres a week.  I keep all types of shrimp including pure TB and have been keeping my RO water this way for about 2 years now. I have had no problems what so ever with my shrimp -infact at the moment I have way too many shrimp. So while you need to be careful I don't know that you need to be clinical. the main issue I find with storing the water outside is the temperature difference so in summer I bring buckets of water into the shrimp room the night before I use it to get the temperature down -it's been quite hot and that would be a disaster- if it is still too warm the next morning I add ice packs until it reaches the desired temperature. In winter I warm water in the microwave and add that to the bucket until the water is warm enough. I use a laser temperature gun to get the temp in the bucket the same as in the tanks. I have 12 tanks  and really have not had an issue with this. The lid on the bin does stay closed though not sealed except when I want a jug of water but mostly I use the connected pump and hose system that is connected to the wheelie bin. I do make sure I change my filter membranes as recommended. I believe we need to be careful but know of quite a few people here in SA that use this system.

[jayc]

I am. But the question was asked how long it would last. It can last months if the conditions are right.

In your situation, the water is being used up constantly. It's not being stored for months.

I did say that if you are using it up, any container with a lid will be enough. 

1 hour ago, jayc said:

If you know you will use it within the next couple of weeks, then you don't need to be too careful. Any clean container with a lid will do

 

[Ronskitz]

Ok so iv just gone and got new sealed containers but to sterilize them do i just use boiling water?

[jayc]

1 hour ago, Ronskitz said:

Ok so iv just gone and got new sealed containers but to sterilize them do i just use boiling water?

yes.

[ineke]

Oops that will teach me not to come in half way through a question??

[paudie]

Thanks for all the info lads I'm working on getting it all together. Onahve 2 choices for the di filter either a 10" housing or a clip onto the RO membrane housing I take it there's no difference which one I go for

Paudie

 

[jayc]

1 hour ago, paudie said:

2 choices for the di filter either a 10" housing or a clip onto the RO membrane housing I take it there's no difference which one

No idea mate. 

Might have to ask the people you are buying it from, which is the better option & what the difference/advantages of each are.

[paudie]

Yeah me either man. Thanks for all the help I'll look into it and post what they say about the difference between both

[paudie]

Hi lads just to let you know what I found out about the DI resin sizes. They say that the 10" housing is better because it holds more resin and last longer. Its holds about a litre of resin so I'm not sure if its a sales pitch or not but makes sense about lasting longer I'm going to order one of them so I can put my RO unit together and get it working Paudie