top off water for freshwater aquarium

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lossam8199

Aquarium Advice Apprentice
Joined
Mar 4, 2014
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I'm having some trouble getting a straight story or any reliable information from the internet about whether or not to use RO/DI water for topping off my freshwater tank. I understand that tap water is better suited for initial set up and water changes so I am specifically referring to topping off due to evaporation. It would seem to make sense that using use tap water for evaporated top off would eventually increase the concentration of "stuff" contained in the tap water and that RO/DI would keep those concentrations consistent. However, this doesn't seem to be normal practice. Any thoughts on this from the experts out there?


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I'm having some trouble getting a straight story or any reliable information from the internet about whether or not to use RO/DI water for topping off my freshwater tank. I understand that tap water is better suited for initial set up and water changes so I am specifically referring to topping off due to evaporation. It would seem to make sense that using use tap water for evaporated top off would eventually increase the concentration of "stuff" contained in the tap water and that RO/DI would keep those concentrations consistent. However, this doesn't seem to be normal practice. Any thoughts on this from the experts out there?


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Makes sense to me, I'd go for it.

On the other hand as the concentration of minerals build up, you end up taking more out with each water change so the tank would stabilize at a slightly higher GH than the tap water. I feel like using RO/DI water would be a great choice, but if you have glass tops and a tank that isn't very large I don't think getting RO water just for top ups is really worth it.
 
I cant say for certain, as long as you're performing your appropriate weekly water changes and the top offs are less than 5% total volume? Treated tap water should be fine. That's what I use anyways. I think the Rodi comes into play for sw setups as the wc's are usually bi weekly and tds is a big factor.

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Topping Off the Tank

I'm having some trouble getting a straight story or any reliable information from the internet about whether or not to use RO/DI water for topping off my freshwater tank. I understand that tap water is better suited for initial set up and water changes so I am specifically referring to topping off due to evaporation. It would seem to make sense that using use tap water for evaporated top off would eventually increase the concentration of "stuff" contained in the tap water and that RO/DI would keep those concentrations consistent. However, this doesn't seem to be normal practice. Any thoughts on this from the experts out there?


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Hello lossam...

No need to use special water to top off the tank. I keep a 5 gallon bucket of treated tap water for topoffs. It's the same water that goes into the tank when performing a water change.

Change out the tank water often enough and the water chemistry will always be stable.

B
 
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