20 Gallon Tank 20% water change yesterday, safe to do 40% today?

[Mahis]

Tank
What is the water volume of the tank? 20G
How long has the tank been running? 2.6 years
Does it have a filter? Yes
Does it have a heater? Yes
What is the water temperature? 25C
What is the entire stocking of this tank? (Please list all fish and inverts.)
4 skirt tetras
1 platy
Maintenance
How often do you change the water? 2 weeks
How much of the water do you change? 20-25%
What do you use to treat your water? Prime
Do you vacuum the substrate or just the water? The substrate



Feeding
How often do you feed your fish? Once a day
How much do you feed your fish? ½Tbsp
What brand of food do you feed your fish? Topfin
Do you feed frozen or freeze-dried foods?

Explain your question
I did a 20% water change yesterday, and want to do a 40% water change today. Is it safe and should I do it.

 

[Slapp]

It should be, those are pretty resilient fish.
Just make sure the water is either room temperature or tank temperature and add it slowly. But that's for any water change not just one after a 20%.
The question is why? Is this an emergency? Otherwise, I would just recommend 10% every day for a week.
I do daily 10% on my 36 gallon because it's been neglected a little bit. In fact, I did 4 in one day and the fish didn't care at all.

What's the cause of the water change? Dead fish? Other spikes?

 

[mattgirl]

Water changes are almost never a bad idea. The only time I ever recommend caution is if regular water changes haven't been done on a tank. If you have been doing your weekly water changes then even changing out 40% of the water daily shouldn't be a problem.

I do have to ask you the reason for the 20% yesterday and wanting to do 40% today? Are you experiencing a problem?

 

[Slapp]

I do have to ask you the reason for the 20% yesterday and wanting to do 40% today? Are you experiencing a problem?

Yeah I'm wondering that too.

 

[Mahis]

It should be, those are pretty resilient fish.
Just make sure the water is either room temperature or tank temperature and add it slowly. But that's for any water change not just one after a 20%.
The question is why? Is this an emergency? Otherwise, I would just recommend 10% every day for a week.
I do daily 10% on my 36 gallon because it's been neglected a little bit. In fact, I did 4 in one day and the fish didn't care at all.

What's the cause of the water change? Dead fish? Other spikes?

I neglected it for a bit so I want to make it nice and clean

Water changes are almost never a bad idea. The only time I ever recommend caution is if regular water changes haven't been done on a tank. If you have been doing your weekly water changes then even changing out 40% of the water daily shouldn't be a problem.

I do have to ask you the reason for the 20% yesterday and wanting to do 40% today? Are you experiencing a problem?

I've neglected it for a bit so I'm worried.

 

[Slapp]

Can you test your water? If your nitrates are under 40ppm its no cause for emergency. That stocking in a 20 gallon with regular feeding would take a month maybe 2 months of neglect to get that high, especially if it's planted. And even at say 80ppm, your fish are used to it, so it's safer to take it down slowly.

Don't panic, it's the worst thing you can do in the hobby.
Save for impulse buying.

If you want to make it nice and clean, vacuum the substrate, clean the filter, clean the glass. The water is the last concern when it comes to cleanliness because the water doesn't make ammonia.

 

[mattgirl]

I neglected it for a bit so I want to make it nice and clean

I've neglected it for a bit so I'm worried.

If the fish handled the 20% water change you may want to just gradually build up to the bigger water changes. Since you changed out 20% yesterday change out 25% today, 30% tomorrow. Continue changing out 5% more daily until you are up to 50%. By doing this you will be gradually acclimating your fish to fresh clean water.

 

[Slapp]

If the fish handled the 20% water change you may want to just gradually build up to the bigger water changes. Since you changed out 20% yesterday change out 25% today, 30% tomorrow. Continue changing out 5% more daily until you are up to 50%. By doing this you will be gradually acclimating your fish to fresh clean water.

Yeah, you don't want to have a reverse nitrate shock. The worst thing to look out for would be pH. It naturally lowers over time, so if your water source is pretty basic take it slow. Again this is definitely something to test for.

 

[Mahis]

If the fish handled the 20% water change you may want to just gradually build up to the bigger water changes. Since you changed out 20% yesterday change out 25% today, 30% tomorrow. Continue changing out 5% more daily until you are up to 50%. By doing this you will be gradually acclimating your fish to fresh clean water.

Can you test your water? If your nitrates are under 40ppm its no cause for emergency. That stocking in a 20 gallon with regular feeding would take a month maybe 2 months of neglect to get that high, especially if it's planted. And even at say 80ppm, your fish are used to it, so it's safer to take it down slowly.

Don't panic, it's the worst thing you can do in the hobby.
Save for impulse buying.

If you want to make it nice and clean, vacuum the substrate, clean the filter, clean the glass. The water is the last concern when it comes to cleanliness because the water doesn't make ammonia.

I'll try to test tomorrow if I can since petsmart opened up today finally but I also want to know that if i did a water change yesterday as per my bi-weekly schedul would a 40% water change tomorrow will be beneficial to the fish

Someone please respond soon. I tested my water and they said my nitrates were high but didn't give me any numbers. They told me to do a double 40% water change 20 minutes apart for today, tomorrow, and the day after tomorrow. Is it safe to do this?

 

[Lucy]

Without the numbers it's really hard to advise if that's even necessary.

Technically it should be fine. I've had to do a few 50%'s in a day a few times because of high nitrates but again, the actual reading really would help.

 

[Mahis]

Without the numbers it's really hard to advise if that's even necessary.

Technically it should be fine. I've had to do a few 50%'s in a day a few times because of high nitrates but again, the actual reading really would help.

It was very magenta/pink when it should of been white. It was between 40 and 80. So it's safe to do 2 double 40% water changes today, tomorrow, and on Monday? (2 on each day for 3 days straight)

 

[Lucy]

Without knowing anything about your tank or what " magenta/pink when it should of been white." might mean I would say it's probably ok to do 2 water changes a day if need as long as the temperature, pH, etc aren't fluctuating.

 

[Coradee]

Hi, yes it’s safe to do back to back water changes.
To avoid overly stressing the fish try & temperature match the new water to the old as closely as you can, but don’t worry too much, a few degrees difference isn’t an issue.
Don’t forget the dechlorinator if you need to use it.

Edit: just had a thought.... have you tested your tap water?

 

[Mahis]

Without knowing anything about your tank or what " magenta/pink when it should of been white." might mean I would say it's probably ok to do 2 water changes a day if need as long as the temperature, pH, etc aren't fluctuating.

Was referring to this:

 

[Flyfisha]

It is always ok to do 40% water changes .
When you are talking back to back on the same day that fine to.
In my opinion you should wait longer than 20 minutes between each 40% change.

I have done more than one change in one day but I wait a few hours.

 

[Mahis]

It is always ok to do 40% water changes .
When you are talking back to back on the same day that fine to.
In my opinion you should wait longer than 20 minutes between each 40% change.

I have done more than one change in one day but I wait a few hours.

And its fine to do back to back 40% for 3 days straight?

 

[Lucy]

Thank you for the picture Mahis, that helps to see what range you're in.
May I suggest you get your own kit? Maybe you won't need to do them tomorrow and the following day,

Like Flyfisha said, yes you can do more than 1 water change per day just space them out.
Coradee added some good info as well.

(Welcome to FishLore!! Sorry, forgot to actually say hello )

 

[Mahis]

Thank you for the picture Mahis, that helps to see what range you're in.
May I suggest you get your own kit? Maybe you won't need to do them tomorrow and the following day,

Like Flyfisha said, yes you can do more than 1 water change per day.
Coradee added some good info as well.

Is it better if I do 2 today, and 2 on Monday

 

[Lucy]

Your readings tomorrow should be your guide

 

[Flyfisha]

Hey Mahis I don’t see why you would need to do quite that many changes 3 days in a row for your species? A water test would tell you how the water is tomorrow.

Nitrates are bacteria poop not actually the bacteria themselves.
Bacteria live ON hard surfaces like your filter and gravel.

As you were only doing water changes every fortnight that is/was the problem.

A local club member that breeds discus and angels has an automatic water change system that changes water before he goes to work in the morning and again at night after his working day . He does these changes every day of the week for months when breeding Discus.

 

[fishnovice33]

Addressing the cause of the nitrates, 1/2 a tbsp everyday is too much food for 4 fish and 25% every two weeks is too little.

Feed two small pinches a day (maybe 1/4 TBSP) and change 50% of the water once a week with dechlorinator.

To answer the question, personally I’d change 40% now, then 40% the next day until nitrates are taken care of. But you may not even need to, and the problem is you don’t know. Need to get your own kit ASAP because no one can answer whether you should or need to without knowing the reading after changing (or the readings of the source water).

 

[86 ssinit]

Was referring to this:

Ok looking at that chart I’m not happy with it. First off nitrates are not going to kill your fish. Even at 120ppm for a few months. But what will kill your fish is going from 120 to 10 in a few days. Not saying your are at 120. First thing that’s most important is how are your fish. Now if no problem with the fish I would just do the 20% for a few days. Than start doing 50% a week.

 

[Mahis]

Ok looking at that chart I’m not happy with it. First off nitrates are not going to kill your fish. Even at 120ppm for a few months. But what will kill your fish is going from 120 to 10 in a few days. Not saying your are at 120. First thing that’s most important is how are your fish. Now if no problem with the fish I would just do the 20% for a few days. Than start doing 50% a week.

Lets say my nitrates are at 60 right now. Would lowering them down to 20 be good. I've actually done a double 40 twice in the past. But I've done them 3 to 4 days apart not everyday for 3 days. And my nitrates went from 200 to 40 and no one died.

 

[mattgirl]

Lets say my nitrates are at 60 right now. Would lowering them down to 20 be good. I've actually done a double 40 twice in the past. But I've done them 3 to 4 days apart not everyday for 3 days. And my nitrates went from 200 to 40 and no one died.

Yes, if you could lower them to 20 that would be good. Once you do try to keep them close to that by doing weekly water changes. Try to determine how much they go up in a weeks time. If they go up to 40 during that time a 50% water change will get them back down to 20. If they don't go that high you can do a smaller water change. If they go higher than that do a bigger one or do one twice a week.

Only you can determine how much nitrate is being produced in your tank. And you can only do that be running to test often enough to determine how much is being produced.

I seldom ever run a nitrate test simply because i change out no less than 50% of the water in my tanks each week and then once a month change out even more. Get in the habit of doing that and you shouldn't have to run the test as often because your nitrates shouldn't get high enough to pose a problem.

 

[emilymg]

I say do the 40% water changes a few days apart until nitrates go down gradually rather than doing them back to back. Too drastic of a change in parameters whether going from low to high nitrate or high to low can stress fish. Those species do tend to be pretty hardy and resilient, but having high-ish nitrates for a day or two won't kill them. A huge swing in parameters though, again, isn't the best either. After the nitrates go back down and all is well, try to do a 50% water change per week vs doing the 20-25% biweekly that you had previously mentioned.

 

[Mahis]

Thx to the ppl who responded. I'm gonna do one more in 3 days time. And last question is it safe to do a 50% weekly change. I thought that would put too much stress on the fish?

 

[Lucy]

Hey, I just want to say we know this can be confusing. I would also say none of the posts are wrong per se, just different, if that helps.

 

[emilymg]

Thx to the ppl who responded. I'm gonna do one more in 3 days time. And last question is it safe to do a 50% weekly change. I thought that would put too much stress on the fish?

A 50% weekly should be okay, especially that becomes the routine for your tank.