Water Change Questions/Observations

[WaterBaby]

I just did a water change in my 20g. I changed about 25% of the water (it was due). I take everything out of the tank when I do this to vacuum a bare tank (except for the gravel). I also scrub the silks and decorations in dechlorinated water.

The tank did not have ammonia or nitrites, but the nitrates were high (60ppm or above). All of the replacement water parameters were as near to the tank water values as I could get. The only thing that was a little different was the pH (tank 7.8 / replacement 7.4 to 7.6). I do not add additives to my replacement water except for Bio-Coat, and I use water that has been standing for about a week in a 5gallon bucket.

I noticed that after the water change, one of my cories started to flash intermittently around the bottom of the tank for awhile. He has since calmed down and seems to be doing fine, although I will keep an eye on him. Could this be due to sediment floating around the tank from the cleaning that irritated his gills? Or something else...

I also noticed that one of my red eyed tetras is missing??????? No clue as to where he went. I have had cannibalized fish in the tank before, but there's no trace of him. Maybe he jumped out and one of the cats got him. It's a mystery.

By the way, I got the nitrates down to 10-20ppm.

 

[TKOS]

Well for starters you should never clean all of your decorations. The surface of these is where the valuable bacteria grows that helps to keep the fish healthy.

Nitrates will build up over time and are just removed using a water change. They are the end product of the bio cycle in the tank (ammonia-nitrite-nitrate). So all you need to do is gravel vacuum around the decorations and do a water change. Cories can be a little skittish so doing all of that work might have just freaked him out too much and he panicked.

When you do this cleaning do you remove the filter media? You should just rinse it out and reuse it as this is also a major source of bacteria. All of this cleaning is actually worse for your fish, unless you do water changes twice a week.

 

[WaterBaby]

I do not replace the sponge. I just rinse in the wastewater from the tank.

I do however replace the carbon pack occasionally (as I did today).

I clean every 2 weeks, and next time, I won't remove everything to clean. Although I must admit that I hate the algae buildup on everything (I have a thread running on the Catfish Forum regarding this).

Thanks TKOS

 

[TKOS]

If you really hate the algae build up then I would buy a scrub brush specifically for the aquarium and every so often take a decoration out and just dry scrub it or else use old tank water then replace the deocration. This shouldn't hurt the bacteria too much and will still let you have a clean look.

If the algae is really bad then you might want to figure out how to slow it down a bit. It would be due to too much food, either from over feeding or not changing the water enough. Add to this too much light and you will get algae. Less light during the day can often be a big help, unless you have live plants.

 

[JSchmidt]

Cories are notoriously spastic fish, so I wouldn't worry too much about him zipping around. He might just be happy with the new water...

You don't have to worry about chloramines if you're adding BioCoat, so it's not likely the fish are being irritated by the water change. I doubt the slight pH difference would be the cause either.

I wouldn't worry about cleaning your decorations. If you have a decent filter, it probably houses more than enough bacteria to oxidize ammonia/nitrites. If you wanted to be cautious, you could clean the filter media at different times than the tank contents.

Unless you see clear signs of distress, I wouldn't worry too much about your water change regimen. Many fish become more active after a water change -- it seems to stimulate them. (In the case of some species, it stimulates them to breed, definitely a sign they like it!)

HTH,
Jim