Best drinking water filter to fill the tank?

StephenHall

AC Members
Mar 18, 2010
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Oklahoma City
I've heard people talking about using reverse osmosis water to fill their fish tank. I've been reading about some RO systems and they claim that with the use of the attached carbon pre filter, the RO membrane filters out 95% of all the dissolved solids and chemicals in the water.

I guess my questions are:
What's the best filter? (RO, Activated Carbon, Still filters, Mechanical house filters, etc.)
Does it really help? Is it needed?

If you use, or have used one of these filters please comment...
 
Generally for freshwater, it's fine to use tap water as long as its treated appropriately. RO water is usually used in SW setups. There could be reasons your particular tap water is unsuitable, but in general it's fine.
 
Generally for freshwater, it's fine to use tap water as long as its treated appropriately. RO water is usually used in SW setups. There could be reasons your particular tap water is unsuitable, but in general it's fine.

I agree. If you do use RO for your freshwater setup you will need to add back some of the minerals that have been removed since fish need them in order to maintain the proper osmotic balance.

In general, unless your tap water is toxic for some reason, I recommend just using a water conditioner. The reason why the saltwater people use it is because it allows them to maintain their salinity when replacing evaporated water.
 
Hmm, mixed feelings. Thanks for the replies. Those are good plausible concerns with the minerals. I will need to look into that. One argument that I heard for RO is that if you put pure water into the tank, it will help with keeping the tank water crystal clear and pure, and supposedly healthier for the fish.

I don't know any thing concerning this topic, and I'm having trouble finding hard data to prove one way or another, so I'm looking for every one's opinions. I respect my community of fellow aquarists and I want to know what you all think. So please post your thoughts...
 
RO/DI units will remove over 95% of everything in your water.
it is nearly devoid of all TDS.
this also removed calcium carbonates from your water which help to buffer pH of the water.
use of 'pure' water is often done in situation where you need to control what is going into the water as in marine systems or other sensitive fish.
 
Thanks for the replies! I have this thread going on another forum. I'm hearing a lot that it's mostly just used in marine tanks. A lot of people saying it's simply not needed in freshwater, and a few people saying it can actually harm the fish. Not very many responses saying to do it.

Still looking for more opinions...
 
it is a must for a marine set up but not needed in most FW set ups.
there are some instances where the reasons to use it is needed. Altum angels for instance should be maintained in a low TDS acidic water condition. they can slowly be acclimated to regular water(if you choose) but when they first arrive they should be kept in acidic water.
ammonia is less toxic and bacteria cannot flourish in this water condition.
 
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Well thanks for the help guys! I'm moving in a few months so I probably won't make any decisions until I test the water there.

I'm still open to any thoughts and opinions if you want to share...
 
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