100% water change

[freakmaster]

hello fish lovers,

i've been doing 100% water change to my 2 fish tanks every 2 weeks......my first fish tanks are stocked with 9 blood parrots while the 2nd one is stocked with a flowerhorn. so far, i have not bumped into any problem of doing a 100% water change, i mean the fish became active again in an hour or so........

however, in many forums and websites that i have visited, i noted that 100% water change is not recommended.....and the thing is that i have not encountered any problem with it so far....so can anyone pls explain.......

and one more thing.....can anyone pls enlighten me on the reason behind doing a 20% or 50% water change???

thank you in advance!

[deep_end]

FM,

Most of the time, we do not advocate doing 100% water changes, because the new water could be totally diff. from the old water, in areas like dissolved O2, CO2, pH, KH, GH, temp., and lots of other stuff that your fish would have to get accustomed to. During this period, they will be under a certain amount of stress, and if weakened too much, could succumb to infections.

A 20 - 50% water change is normally done to remove excess NH4+, NO2- and NO3- ions from tanks that may not have efficient bio-filters. Usually it's those hobbyists that use only mechanical filters that change so much water.

[kevkoi]

Both fish (Parrot and FH) that you're keeping now are tough as nails!! Not many other fish are as tough as the fishes u're keeping now. If you try doing 100% water change on many other types of fish (without aged water), u're likely to get dead or sick fish. Trying doing 100% water change on fish like Rummy nose Tetras. I'd bet they belly up with the sudden change in water chemistry.

There's no point in doing 100% water changes anyway so why spend the extra time (and risk your fish). 50% a week is plenty (and u never have to remove the fish from the tank!).

[freakmaster]

Thanks for the info,

I have since 'converted' to doing 50% water change fortnightly. And occasional 100% water change if the water is too cloudy. However, before the 100% water change I religiously do 50% water change every week for 2 weeks in a row...so as to get the fish accustomed to the new water...

[deep_end]

FM,

One more reason why you might need to do a 100% water change is when your NH4+/NH3 or NO2 levels are off the chart. NH4+/NH3 usually shows itself as very fine bubbles sticking to the glass at the water surface. If NO2- levels are high, your fish will usually be gasping at the surface. The best way to tell would be to invest in NH3/NH4 and NO2 test kits. They last a long time, and you can use it for any of your fish tanks.

[freakmaster]

Originally Posted by deep_end

NH4+/NH3 usually shows itself as very fine bubbles sticking to the glass at the water surface.

Hmmm...I always thought this is attributed to the dissolved salt in the water or so I heard...

Comments???

[deep_end]

Nope, FM.

You can try RO or distilled water with a high level of NH3/NH4+ in it, and you will still see the foam. In marine tanks, even in the absence of any NH3, you will ALSO see the foam that is typically produced by a protein skimmer.

[goo]

Hello Deep_End,

Your explaination is deep and very accurate, I like your professionalism. Keep it up!

[corey]

First off I would like to say hello to everyone. This is my first post and am looking forward to giving my 2 cents when I can.

100% water change NEVER, NEVER, NEVER....................

If you water is cloudy you are not doing something right. If you water becomes cloudy do a 25%-35% water change every 3 days untill it's clear. Freakmaster maybe you can post your tank size, lighting, filters , water parms PH GH KH etc.... and I will be able to help you in more detail.