Distilled water for Top Off??

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

jmay33

Aquarium Advice Addict
Joined
Nov 12, 2012
Messages
1,746
Location
Texas
Can I use distilled water to refill my tank when the SW evaporates?
 
You'll be fine if your just topping off with distilled. A lot of people do it including myself. Never had an issue yet.
 
Just thought I would throw in my two cents here...

Everyone seems to agree that distilled water is ok to use, as it falls within the proper parameters for an aquarium. However, distilled water is not "perfect" water, and there is a lot of debate as to whether or not you really should use it.

I have been having this same debate with myself and my current tank, but honestly, do you really want to be purchasing distilled water forever, knowing its not the best water available for your precious ecosystem! I bit the bullet and bought me a 4-stage RO/DI unit from Bulk reef supply ($138 custom built). And it goes right under my sink, I get 100% clean water for my little pets, and for the freshest and safest ecosystem available! I also fill both of my other freshwater tanks with the water, drink the RO water for personal use, and can have water whenever I need it. Over the lifespan of an RO/DI unit, you will save a lot of dollars, a lot of hassles....and it is pretty cool trying to explain to your friends why you have this super cool water cleaner thing in your bathroom! :cool:

So in my less than professional opinion, go ahead and get an RO/DI unit...it will never hurt you, and you will officially jump start your aquarium hobby to full load knowing that you have the ability to grow any corals or fish that you may need and you have the cleanest water on the block!
 
Contrary to belief distilled is far from perfect amd many brand ive used and tested contain a significant amount of phosphate between .1 and .25 also TDS from 25-100.

Distilled caused me phosphate problems in the past resulting in algae outbreaks. The tds is also higher than RO so who knows what else is in it.

I would only use it if you get a clean phosphate reading. Constantly pouring phosphate into your tank will have negative effects.
 
I'm using distilled water for now. I'm glad to know it is safe for what I have. I do want to invest in a RO/DI system in the future though. Thanks everyone for the great information!! :fish:

Edit: I finally got an API test kit in the mail yesterday, so I've been playing with it a lot. Lol. The distilled water I used was clean of phosphates. :) thanks for telling me to test it first.
 
If you want to get a good test kit for PO4 get a Hanna HC736 ULR or Red Sea Pro. Don't stay with API they are the second to worst in accuracy , first being the strips. When it comes to test kits you get what you pay for.
 
Nobody said distilled water is "perfect" I'm not sure any water is "perfect"

Simple answer is yes you can use distilled water for top offs. I've been doing it for over a year and some have been doing it forever.

Distilled will work, ideal RO/DI I agree with that.

Find me something that's "perfect"
 
Last edited:
Nothing is ever perfect there is always room for improvement. :) I used the ro from the machines at the grocery store for my pwc and top off for the first ten months of haveing my tank. Had a little algae on the sand but nothing that would overfeed my cleanup crew. I asked for a rodi for Christmas killed two birds with one stone. Lol next year maybe a bigger tank........
 
Back
Top Bottom