Is it okay to do a 75% water change?

[screaminleeman]

I don't keep sensitive fish species. I change over 75% in a clip almost always. Only once I managed to "kill" some fish. I left a 125 G outdoor pond siphoning while eating Dinner and forgot about it. I remembered hours later and filled it back then. The couple of juvenile Koi kicked the bucket along with maybe half a dozen golden shiner minnows. I lost maybe 2% of the rosey red minnows.

Hours without water is not conducive to your fishes health from my observation. Dozens of times I have ran the water dry siphoning, but always was filling it within a handful of minutes of emptying it.

I am NOT suggesting you do this, I am only mentioning this from a worst case scenario in massive WC's.

 

[RD.]

I also routinely do massive water changes, 80-90% weekly. So what?


Osmoregulatory shock is very real, and with rays only an idiot would do a massive water change when parameters are off such as what the OP stated. If the nitrates are sky high, then other parameters are probably off as well.

 

[Mymonsterfish]

I usually do a weekly wc of 30% but recently added 2 new rays

 

[Mymonsterfish]

I've also been doing about a 20% wc every night for the past 4days. Is it too excessive?

 

[xraycer]

I usually do a weekly wc of 30% but recently added 2 new rays

For a tank with standard filtration system, 30% once a week is not enough. That nitrate will just keep on building. I already gave my w/c recommendations a few posts back

 

[rodger]

I don't know squat, so I won't comment.

 

[Drstrangelove]

Yes. Done many over 75%. And sometimes, you have to do it if conditions in the water deteriorate and fish health is threatened.

Fresh clean dechlorinated water is a pretty good thing to give fish. If you have particular species that need smaller water changes, you just have to do them more often.

 

[mscamp02]

my rays have never like massive changes and generally stress, I try to do frequent 20-30% changes on the 225 that is not hooked up to my auto drip. However stock is one flower and one small mantilla with a 50 gallon sump so bio load is not through the roof.

 

[Mymonsterfish]

Cool, and what do you guys think about ro water system. Just bought one and was wondering if it's better or just the same as adding prime to tap water? Will the ro system help prevent nitrates from tap water?

 

[spiff44]

Sure its doable but don't ignore the fact that the larger percentage of water change, the more critical it is to match parameters and the higher the possibility of problems. If you start stressing or killing things I would scale back.

With something like rays I would err on the safe side and go with smaller and more frequent changes.

And take what all people say with a grain of salt. Like you gotta love it when someone's response to a WC change question is to say they don't do anything... even if that was true, that's a rare exception that you're able to get away with that. There are only two reasons why someone would even say that in response to the OP's question and neither one of them are good.