Distilled Water

[Ivan Mann]

I have tap with a pretty high GH rating. For years I replaced evaporated water with tap water and had a GH rating way off the scale. I changed a whole lot of water and have that back in range now, but I wind up replacing 5 or 6 gallons of evaporated water a week with distilled water from the grocery store, and it is sort of a pain to carry them around and then toss the gallon jugs in the recycle. Is there an easier way to replace evaporated water?

I have three tanks, a 55 gal, a 30 gal, and a 20 gal.

 

[seangee]

If your tap water is within an acceptable range regular water changes will help. When water evaporates it is only water and minerals and nitrates remain in the tank, which increases the concentration. Weekly large water changes will clear these out.

 

[Byron]

Topping up evaporated water makes things much worse for the fish if this is all you are doing. A once a week partial water change of a significant volume of the tank water is necessary for fish health. I change 60-70% of each tank's volume every week.

As for the GH, what is the GH of your tap water? Also the KH (Alkalinity) and pH would be helpful to know. And what fish species do you keep? The GH (and associated pH) may or may not be a problem.

 

[PheonixKingZ]

Ok, here we go...

I have the same “Problem” as you do, because 50% of my tanks are lidless. I end up replacing about 4 gallons per week.

I think buying distilled water from the store is a complete waste of money. I use Tetra AquaSafe for all of my water. I fill a 1g milk jug full of tap water, and then put the correct amount of AquaSafe in with it, and mix it up. It instantly converts the tap water into safe aquarium water, along with a lot of other helpful minerals/slime coat.

I currently keep around 5, 1g milk jugs around with “safe” water in them.

Here’s a link to the stuff I use: https://www.amazon.com/dp/B00068JW0A/?tag=ff0d01-20

 

[seangee]

I have the same “Problem” as you do, because 50% of my tanks are lidless. I end up replacing about 4 gallons per week.

Please take note of posts #2 and #3. If you top up between changes then you need to do a larger regular change. E.g if you replaced 20% of the water during the week you still have 100% of the nitrates in the tank because they never left with the water that evaporated. And your calcium (or any other minerals) will have increased by 20% - all of the original minerals are still in the water and then you added more when you topped up.

 

[Essjay]

Think of it like this, -
You have a 100 gallon tank. 5 gallons evaporate; the tank now holds 95 gallons of water but 100 gallons worth of minerals. You top it up with 5 gallons tap water. The tank now holds 100 gallons water and 105 gallons worth of dissolved minerals.
Another 5 gallons evaporates; the tank now holds 95 gallons water and 105 gallons worth of minerals. You top with another 5 gallons tap water. The tank now has 100 gallons water again, but now with 110 gallons worth of dissolved minerals.
And so on.

If water evaporates so quickly that it needs to be topped up between weekly water changes, distilled or RO water should be used as they contain no minerals, all they add is water and the dissolved stuff in the tank remains the same.

 

[Ivan Mann]

Sparing most of the math, if five gallons evaporate out of 55 gallons and I then remove 40 gallons and replace with 45, the gh goes up by about 2%. Next time it goes up slightly more in a divergent series and there is no limit to the chemical concentration of tap water chemicals. Changing less than 40 gallons changes at a higher rate. I had been doing that for ten years and the concentration was way off the scale. GH for tap water here is 225 ppm. The water test kit I used said to count drops and the table stopped at 14 drops to change color. At 42 drops it hadn't changed color and I stopped wasting the chemical. Now it changes at 12 and all the fish look happier.

The problem remains. Isn't there a better way to get distilled or similar water without throwing out gallon jugs every week.

 

[Naughts]

Do you have full lids on your tanks?
My shrimp tank has a plastic lid that sits on the top with some significant gaps - I get evaporation. My fish tanks are fully covered by their lids - there is no discernable evaporation.

 

[Byron]

It would be better to address the evaporation itself. This should not be occurring at such a high rate. Keeping the tank covered is advisable not only to stop the evaporation, but it is safer for the fish. And all that moisture that evaporates ends up in the structure (walls, ceiling) and that is not good for the building.

RO water mixed in with tap water at water changes would reduce the GH at each water change. This is a proportional change, so 50% tap mixed with 50% (equal amount) of RO would reduce the GH by half, and so forth. Depending upon the fish species, you could work out an ideal preferred range.