Water change technique

[Deadeye]

I think you have a great idea about emptying the tank down to only 10 or 20 percent full; I would do it every week, and then just fill it back up with fresh clean water of the correct temperature, de-chlorinated of course if necessary, and then sit back and enjoy my fish.

Like Esox said, once you have all your water changing stuff set up and ready to go, might as well get the most bang for your buck. Do it weekly; the only possible shock will be to you, when you see how quickly your water parameters improve and how stable they will then remain. Your fish will love it.

I’d agree, but it looked like it was going to be filled over the course of 3 days. I can’t imagine the fish enjoying that. If filled right back up the bigger water change the better though.

 

[jjohnwm]

I’d agree, but it looked like it was going to be filled over the course of 3 days. I can’t imagine the fish enjoying that. If filled right back up the bigger water change the better though.

That was my point; waiting to fill it up makes no sense. Take out as much water as you can, replace it with new. As long as you haven't been monkeying around with the tank water, trying to soften it or harden it or change its pH or whatever, you will be fine. The water you take out and discard came from the same tap from which you are getting the new water. You're taking water that is full of fish waste and replacing it with the same kind of water that isn't full of fish waste; it's literally that simple.

Less analyzing, more doing.

 

[ken31cay]

I like this thread since it's about large, frequent water changes. Our fish love them. I like to replace at least 75% each time I do a wc.

Only time I ran into trouble was with Discus. I used to do ~80% daily water changes so you'd think there would be a small difference between the current day's tap water (~6.4 pH) and yesterday's water (~6.9 pH) which was in the tank. But even that small difference apparently affected my Discus and only when I allowed the water to off-gas in 55gal drums overnight did my fish get happy with the large water changes.

But the vast majority of fish are going to have no problem with large water changes, that is unless you start messing with buffers, etc., as mentioned in the post above.

 

[FINWIN]

Your fish will dictate your w/c schedule. My determinator is my oscar. As he grew so did the water changes. 50% once a week then twice a week were a waste of time. Now I do 90% clean once a week. All the fish enjoy the freshness. My O will swim wildly in circles, back and forth, then do loop-de-loops. He even punches the python hose while water pours over his head. The other fish get fiesty and start sparring with each other!

Since going with single large changes there's been no issue. Only time I might do twice a week is a growout tank. As babies my acara pair got changes 3 times a week with small meals all day. The male is now 7 inches, the female around 6.

 

[Fish Tank Travis]

When I had my 220 I did fin level water changes every weekend. I would even let the sump pumps drain that back into the tank so that I got well over 200 gallons out into my front yard. I kept two 55 gal drums with aged and heated water that I pumped back into the tank along with straight hose water to complete the refill. In the winter the temp would slowly drop by about 20 degrees. The fish were all fine and healthy with this regimen.

 

[ken31cay]

Your fish will dictate your w/c schedule. My determinator is my oscar. As he grew so did the water changes. 50% once a week then twice a week were a waste of time. Now I do 90% clean once a week. All the fish enjoy the freshness. My O will swim wildly in circles, back and forth, then do loop-de-loops. He even punches the python hose while water pours over his head. The other fish get fiesty and start sparring with each other!

Those are some happy fish! Oscars can be such fun though. Started with six in my 180gal, down to the two best looking ones which are now around 9". I'm hoping they'll make it together somehow as they reach adulthood.

 

[TwoHedWlf]

Hi guys

In my biggest tank the nitrates are a bit high mostly so I was thinking about the water changes like this sometimes Instead of doing 30 or 50 percent change
Empty the tank almost and leave 10 to 20 percent of old water and full up the tank to 1 third first day half next day and full day after. What do you think about that. Also I don't feed on Sunday but was thinking bout 1 day on 2 now.

Thx

I wouldn't take 3 days to refill it, if you're doing water changes reasonably frequently you're not going to have hugely different parameters. Maybe refill it over an hour or two. Whatever rate is convenient slower than refilling it full blast from the garden hose.

 

[Trouser Cough]

I change as much water as my hot water heater will let me get away with. In larger tanks I've found that (at least w/my plumbing system at my house) that if I connect a 3/4" garden hose to an adapter at the bathroom sink I can turn both hot and cold valves on full throttle and the temp at the tank remains remarkably consistent. My guess is that an older house or an older faucet might be different and if you have the kind of plumbing that when someone flushes the toilet whomever's in the shower gets scalded... it probably won't work well.

 

[Karalak42]

That was my point; waiting to fill it up makes no sense. Take out as much water as you can, replace it with new. As long as you haven't been monkeying around with the tank water, trying to soften it or harden it or change its pH or whatever, you will be fine. The water you take out and discard came from the same tap from which you are getting the new water. You're taking water that is full of fish waste and replacing it with the same kind of water that isn't full of fish waste; it's literally that simple.

Less analyzing, more doing.

I like this thread since it's about large, frequent water changes. Our fish love them. I like to replace at least 75% each time I do a wc.

Only time I ran into trouble was with Discus. I used to do ~80% daily water changes so you'd think there would be a small difference between the current day's tap water (~6.4 pH) and yesterday's water (~6.9 pH) which was in the tank. But even that small difference apparently affected my Discus and only when I allowed the water to off-gas in 55gal drums overnight did my fish get happy with the large water changes.

But the vast majority of fish are going to have no problem with large water changes, that is unless you start messing with buffers, etc., as mentioned in the post above.

How do you mean off Gass?

 

[ken31cay]

How do you mean off Gass?

Tap water will contain some dissolved (pressurized) gases, ex/ CO2, which will escape from the water once it is no longer under pressure. The CO2 has an acidic effect on water (lower pH) but once it escapes then the pH of that water will rise.

Out of curiosity, what type of fish are you keeping? Most fish don't mind the small change that occurs from the CO2 off-gassing, but sensitive fish can be affected by this. In colder climates the effect can be increased since the water in the pipes can hold more dissolved gases at lower temperatures.