Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fish Tanks and Equipment => Topic started by: Diz1 on October 21, 2015, 08:37:07 AM

Title: Using a Britax water purifier for RO water
Post by: Diz1 on October 21, 2015, 08:37:07 AM

Morning everyone,
It's been a while since I last posted, but work and holiday have been in the way a bit. Now back and glad to say that all my fish are doing well.

I've been considering using RO water for a project that I'm planning (sometime in the future).
I would need only around 20 litres per week, so I wouldn't want to go to the hassle of getting an RO unit fitted.
I've seen an 8.5 litre Britax filter system on Amazon, which I think might be a good solution for me, but does anyone know if the water it produces will be as good in quality as a proper RO unit/filter?

Thanks

Diz

Title: Re: Using a Britax water purifier for RO water
Post by: Sue on October 21, 2015, 09:56:41 AM

Do you mean Brita filter?

I have a Brita filter jug and have tested everything I can in the water.

Comparing freshly run tapwater with freshly filtered water:

Tapwater - pH 7.2, GH 9, KH 3.5
Filtered    - pH <6,  GH 6, KH 0


Brita filters work be substituting hard minerals for soft, in this case they substitute calcium & magnesium (GH) with hydrogen ions - and pH is an upside down measure of the amount of hydrogen ions, the more there are the lower the pH, which is why the filtered water's pH was off the bottom of the scale with the API tester. They must also substitute something for carbonate but I've not found out what yet.


So the answer is no, Brita filtered water is not a good substitute for RO water as it still has stuff dissolved in it, and it maybe stuff that is not good for fish.

Title: Re: Using a Britax water purifier for RO water
Post by: Sue on October 21, 2015, 10:14:04 AM

From Brita's website

Quote

Is filtered water the same as distilled water?
A BRITA water filter removes substances from tap water which can affect the taste and appearance, it is therefore only partially de-mineralised. Distilled water is totally de-mineralised and therefore filtered water cannot be used where distilled water is required, e.g. car batteries.

Distilled water has been boiled and the steam condensed. In theory it is pure water but some contamination can occur.
RO water is water that has had all the dissolved solids removed by passing through a membrane. Should be pure water depending on the efficiency of the unit.

So if Brita are saying filtered water can't be used in place of distilled water, it can't be used in place of RO either.

Title: Re: Using a Britax water purifier for RO water
Post by: Diz1 on October 21, 2015, 10:55:16 AM

OK, thanks Sue. It's not such a big problem, the Maidenhead Aquatics near me can sell me RO water and the cost isn't that prohibitive given the small amounts I'll need for my tank.
I just don't want the hassle of fitting an RO unit.