10 Gallon water change

[Natureboy71]

So if you have a little 10 gallon tank with very little bio-load (like a couple of tiny fish) and once the water evaporates down to about 20% from full and you just refill it with totally pure steam distilled water would that be fine instead of removing water. Also if ammonia and everything is in check?

I had read online here that just adding if you add tap water will add too many other minerals not needed.

If not, what is the advantage to removing water if everything is in check?

 

[Rbishop]

Where did you read that on-line?

If you follow that, be prepared for a major pH crash.

 

[Natureboy71]

Here actually.

So to complete your response. Because the PH in distilled is neutral or negative, it would slowly lower PH to levels too low for the fish.

 

[Rbishop]

It is the lack of the minerals that would be the issuefor most tanks. In some cases, a mix of distlled/RO may be needed to achieve certain conditions or to compensate for extreme water conditions.

If you just refill with distilled/bottled water in a standard tank, you will have problems. Just topping off with ANY water does not remove the toxins in your tank and you are on your way to OTS and death for the fish.

 

[Marinemom]

Even though your readings come out fine on your water and you can see that the water is crystal clear does not mean that the water is in an ideal situation for your fish. There is a difference between water quality and water clarity. If you want good water quality, I would suggest that you keep up on water changes. The water has something in it called TDS which means total disolved solids. If this gets to thick in the water colomn, then the water conditions wil deteriorate in your tank putting stress on all of the fish in your tank. It will take longer for this to happen if the bio-load in your tank is light but it will still happpen over time. Think of it this way; when your house is completely clean then you feel good but if it is not then you may not feel as good and be on edge. (at least that is the way it is for me). It is the same for your fish. A good water change is like having a freshly cleaned house for them and it makes them feel good and makes them a lot happier.

Marinemom

 

[Ulan]

If the water evaporated down to 20% of the initial value, the fish are now in a five times higher mineral concentration than in the beginning. Just adding distilled water would restore roughly the initial water composition, but have more nitrates and other waste products in it. This means, I'd still do a water change.

Just adding up tap water would, indeed, increase the mineral concentration. However, I would not add 4 parts distilled water to 1 part residual water, because I'm pretty sure that the shock would kill the fish. In this case, I would even be wary of adding tap water quickly, especially if you have hard water. I'd try a very slow approach, in order to give the pickled fish some time to adjust.

 

[dorkfish]

Incase you don't know, after ammonia and nitrite, fish waste and uneaten food are proceesed by bacteria, you end up with nitrate and dissolved organic compounds(DOC's). The nitrate in itself is not really toxic, however, it si a good indicator of DOC's when nothing except water changes is removing it. The DOC's are toxic to your fish as they get into larger concentrations and will eventually kill your fish if left unchecked. The only effective way to remove DOC's is to change your water.

The mineral concentration is only a minute part of the reason(s) why experts long ago detrmined the need for water changes.

 

[plah831]

I totally agree with dorkfish. That's why whenever my tank water levels drop (this is usually if I leave the house for a few days), I do a water change automatically and don't even bother with the topping off.

 

[CaptnDan]

Trying to get ultra pure water for your fish is a noble gesture, but it ain't gonna happen...

If all you do is replace evaporation with RO or distilled water, you will be diluting TDS and other factors contributing to hardness. The processes of distillation and reverse osmosis remove nearly all hardness/TDS. So if you started with something like 20ppm of hardness, then let water evaporate, you might get up to 25ppm. Then you add the distilled or RO water, you have diluted it back to the original 20ppm. Actually, over time you would see in increase (not even counting outside factors) because if you check an RO unit with an electronic TDS meter you will not find a reading of zero. There will be more and more as it comes time to change the filters in the RO.

The main thing we are concerned with in doing water changes, really, is keeping Nitrate under control. If all you are doing is adding to make up for evaporation, you're not just spinning your wheels, you're losing ground. Two things are increasing the Nitrate concentration in your tank. One is evaporation - Nitrates don't evaporate with the water, and of course, your fish are still producing ammonia, which becomes Nitrate.

Reverse Osmosis cannot be relied upon 100% to remove biological contaminants. Neither can boiling. There are heat resistant strains of bacteria that can withstand temperatures well above 100C. The only way to heat water above that temp is under pressure, like in a pressure cooker, or an autoclave. The catch is, as soon as the water comes in contact with air, all bets are off.

Unless there are problems with the water, don't worry about softening it. That hardness can be a good thing. With no hardness, there is no buffering capability, and you could have serious pH problems.