100% water change

TreyGiles

After my marine aquarium cycles, do I need to perform a 100% water change?
 

Naeusu

uhh.....i'm pretty sure you should never....EVER....do a 100% water change. You would essentially be flushing all the bacteria you've been culturing during your cycle. Most people only do a 15-25% water change depending on the size of the tank and the levels of nitrates.
 

Mystic54

I agree with Naeusu. An 100% water change could very well make your tank go into a minI cycle since you would be removing a lot of the benefically bacteria. I think a 10-15% water change for a tank that has just finished cycling would be sufficent.
 

Aquarist

Hello TreyGiles,

I've never heard of anyone doing a 100% water change after cycling for fresh water or salt tanks. I don't have experience with salt tanks but it doesn't sound like a very good idea. I have to agree with the above posters.

I hope you can share some photos with us.
Ken
 

Goldwing_Don

If this is your 75 gal tank i'd do a 10 gal water change and retest the next day to make sure you are cycled... You can do bigger changes after that but I would start out low and work your way up to 20 or 25 gal as you add to the tank....jmho
 

harpua2002

The vast majority of the beneficial organisms live in and on the live rock and substrate. With nothing but rock and sand in the tank, it wouldn't really matter if you changed all the water after your tank cycles. However, there isn't any need to do so. Check the nitrate level after you're sure the tank has cycled, and base the percentage of your water change on your test result.
 

locoyo386

After my marine aquarium cycles, do I need to perform a 100% water change?

HI there,
No, you do not need to perform a 100% water change. I am a firm believer in that the bacteria present in the water is at an extremely small amount compared to the bacteria on the surfaces inside the tank (ie, glass, rock, sand, etc.). Nothing will come out of doing a 100% water change. On the other hand, it is not needed either. Most people that do a water change once the tank has cycled, it's because they want to get their nitrates down, specially in reef tanks. I would recommend checking your nitrates (they might be somewhere around 10-20 ppm). If you want them to go down, then do a 20% water change and do your weekly 10% water change. Note that if you are going to keep reef tank, nitrates have to be kept on check.
 

Naeusu

The vast majority of the beneficial organisms live in and on the live rock and substrate. With nothing but rock and sand in the tank, it wouldn't really matter if you changed all the water after your tank cycles. However, there isn't any need to do so. Check the nitrate level after you're sure the tank has cycled, and base the percentage of your water change on your test result.

It is true that the majority of the bacteria is on the rock and in the substrate but if you remove all the water with a water change that big you'd be removing the nutrients needed for the bacteria to grow. That is what I meant by flushing the bacteria.
 

harpua2002

IMO it really wouldn't remove anything that the bacteria need to grow. Once the tank cycles, there needs to be a source of ammonia present to feed them anyway. The OP could do a 100% water change and add fish (or other source of ammonia) with no harm to the beneficial organisms. It just isn't necessary to put out the effort.
 

hm11

I had to do a 100% water change today because one of my corys died off of I believe Ammonia poisoning, probably some nitrate too. My water was super cloudy, it went from lemon green to white. I have a heater that turns on automatically and in the dark when it turns on it almost looks like a lighthouse in the middle of a foggy night, not kidding. So before I changed all the water I replaced 25% of the water for almost a week and the cloudyness still persist, it was strong. I tested the water and my ammonia levels were to the roof. I'm talking about Dark Cyan, really dark. I thought "maybe it was the ammo lock and such things that are giving me these readings." but afterwards my Cory died and two days passed and decided to change the water and clean the gravel (Today). I will be going to the fishstore and get input from the people there as well, I might be buying Natural wood to stabilize Ph levels and all... I might even get a new filter cartridge..

What are your inputs on this??
 

DougieB

how long have you had the tank running. have you cycled your tank?
 

hm11

teh tank was running for like a bout a month, a friend of mine gave it to me since he was upgrading. The tank was in the midst of cyling through nitrate I believe.
 

Rivieraneo

Hello and good morning!

Please read and make yourself fond of the nitrogen cycle. Also, I believe you're a bit confused on your ammonia readings. The only test that would give you a cyan color reading would be your PH test or nitrite test, though nitrite would be a lighter tone of cyan. Please post all your water test results, ammonia, nitrite, nitrate, and PH so we can offer you better opinions.

The color in your water can either be an algae or bacterial bloom or foreign chemical that has been introduced into the aquarium. Unless you have a reputable LFS, I suggest you wait for advice from fellow fishlorians who love the hobby versus receiving bad advice from a sales person.
 

hm11

ahh I seee. I shal get a new test tube then.
 

Nikita

Hello again.

Please go and read the -> nitrogen cycle. It's essential to keeping an aquarium.

The cloudy water is most likely a bacterial bloom. They are common in new, uncycled tanks. In order to fix this, and for the safety of your fish, I would recommend doing daily partial water changes <25% - 50%> to keep your ammonia and nitrite levels down (at least below .25 ppm). Continue these daily water changes until your parameters are a constant 0, 0, 5 - 20 (ammonia, nitrite, nitrate).

To help cycle your tank and prevent you from tons of work, add a bacterial additive to the tank. I totally recommend using TSS as your bacterial additive, works great and others I've used have failed me in the past. If you are to use TSS, make sure to read the directions. Do not add when more than 1 ppm of ammonia or nitrite is present in the aquarium or under 24 hours of using a water conditioner (either or could affect the results of using TSS). Add the recommended dosage for your tank and wait! It will take around 14 days to cycle your tank with TSS. Within that time period do not do any water changes.

I would also recommend getting a liquid test kit to monitor your parameters (do not use test strips, they are highly inaccurate and give false results). Stop using the Ammo lock, it'll just do more harm than justice.

Do not replace your aquarium filter cartridge. The filter cartridge is where all the beneficial bacteria lies (the stuff that checks your tank stable), replacing it will only cause you to lose your cycle and start all over.
 

hm11

Sweet, Thanks Nikita!
All ihave to do now is keep the water changes going and get a new test tube for the test kit since it broke yesterday.
 

Ant

HI and welcome to fish lore. The other fishlorians are right. Keep coming back to the website and it will help you immensely with your fish. Salespeople at local fish stores know the bare minimum usually, just enough to sell you a lot of fish so they die off and you come back buying more.
 

slade

You've gotten good advice on the importance of cycling. The quickest way to get beneficial bacteria (BB) is if you are lucky enough to have a fellow aquarist willing to give you some used media from their tank.
Good luck, keep up with water changes.
 

Meeps83

Learning about the nitrogen cycle is the biggest obstacle to tackle. The rest will seem like a breeze once you have mastered it. If you do decide to do a fishless cycle (which we do not recommend here) Corys are not the fish to use. Also, lemon green water is not a good color for your tank either. It should be clear.
 

Tetra Guy

I don't think your tank is cycled yet. Another idea to speed up the process should be to put a shrimp in the tank. One that we humans wood eat. The bb would like that. Don't put fish in there until the cycle is complete. Some people will use a cheap feeder fish of some kind to help the cycle, I don't recommend this. It is torture for fish, very stressful.
 

hm11

what do you mean by used media???
 

Ant

It means if you can, find a friend who has an established tank and use the sponge from their filter and put in your filter along with your filter's sponge. The bacteria colony will help your tank. After your tank is cycled you can return the sponge. Some filters have 2 bays and makes this even more possible.
 

hm11

I will try that, since I do have a friend that has a fresjwater aquarium.
 

Teleil

Welcome to fishlore.

You said that the acquarist friend gave you the tank, did you get the tank only or the used filter and gravel/decor?

I suppose you got the tank right after he upgraded? Just want to know this becouse if it happens to be the case then might be something else wrong.
But if you only got the tank and used new filter, gravel, decor then its most likely NC not done yet.

Anyways follow the instructions provided and you'll get it established in no time
 

6037201

I have sand substrate but I don't like it, I don't even know why I got it in the first place. The things I hate about it are it makes the water smells, every time I moved something in the tank the sand would come up too and the water would get little cloudy, its super hard to clean using vacuum cuz I would be sucking the sand up too and its really dirty to dealt with. So basically, I want to switch substrate to something like marble glass, rock shape like.. But the problem is if I'm gonna do that then I'll have to do a 100% water change cuz I need to remove the sand and all. I have a betta and a nerite in the tank right now. I just want to know if its safe to perform such water change.

This is the pic of the sand
 

Bbarb27

Before you distrurb/remove your sand, can you siphon off the tank water into several clean buckets and save it? You'll likely want to remove the water that gets dirty when you remove the sand, but saving some of the water pre-removal could avoid a 100% water change, which could be hard on the fish and snail.

I'm sorry you don't like the sand though. Did you rinse it really well before putting it in the tank?
 

6037201

Before you distrurb/remove your sand, can you siphon off the tank water into several clean buckets and save it? You'll likely want to remove the water that gets dirty when you remove the sand, but saving some of the water pre-removal could avoid a 100% water change, which could be hard on the fish and snail.

I'm sorry you don't like the sand though. Did you rinse it really well before putting it in the tank?

Keep how much water tho? So I just pour the small of amount of water back into the tank right? after I removed the sand



Plz help me out with this
 

el337

What kind of sand do you have and how deep is it? You shouldn't need to stick your siphon into it when vacuuming as all the debris/detritus sits right on top. Just swirl your siphon a couple of inches above the substrate and everything just gets sucked right up. You could stir it once in a while but that shouldn't cause any odors.
 

6037201

What kind of sand do you have and how deep is it? You shouldn't need to stick your siphon into it when vacuuming as all the debris/detritus sits right on top. Just swirl your siphon a couple of inches above the substrate and everything just gets sucked right up. You could stir it once in a while but that shouldn't cause any odors.

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I have sand substrate but I don't like it, I don't even know why I got it in the first place. The things I hate about it are it makes the water smells, every time I moved something in the tank the sand would come up too and the water would get little cloudy, its super hard to clean using vacuum cuz I would be sucking the sand up too and its really dirty to dealt with. So basically, I want to switch substrate to something like marble glass, rock shape like.. But the problem is if I'm gonna do that then I'll have to do a 100% water change cuz I need to remove the sand and all. I have a betta and a nerite in the tank right now. I just want to know if its safe to perform such water change.

This is the pic of the sand
 

el337

I'm not able to view the link.
 

el337

It doesn't appear to be very deep so if you're stirring it enough, it shouldn't cause gas pockets which would be the cause of any odors. What kind of sand is it? It appears very fine but still shouldn't be an issue for any permanent cloudiness. How often and how large are your water changes? Put in some activated carbon if you want to get rid of any odors in the tank.
 

CindiL

As long as you match ph and temperature (check your tap and tank both for ph) its fine to do 100% water change. And also as long as you haven't let nitrates get really high in the aquarium. So check all your parameters first. I have switched fish numerous times into totally new tanks/water and these are the important parameters to check.

Also, I do agree that you don't need to stick the siphon into the sand, just swirl above it. I love my sand tanks. There should be no odor from the sand either. If there is a smell its something else. How big and how often are your water changes? How long has this tank been running?
 

Civanna

Is it safe to do this once in a while?
The quality is perfect but it looks so DUSTY inside.
The sight of it is annoying me
 

Fanatic

What size is your tank?
I only recommend doing it if there's a absolute need to do it. Such as an illness outbreak in the tank, otherwise it's a no.
 

James17

Please don't it's not necessary, 25% water changes are usually enough, If you'd like you can just do them more often.
 

AllieSten

Yes it is safe to do it once in awhile. But I would try to solve the problem another way, First.

Do you have carbon in your filter? This will give your water a more sparkling appearance. It acts as a polish. So that may help. Also using filter floss will help get all those tiny particles out of your water.

Are you sure it isn't the film on the inside of your glass? It can make the water appear as if it has a dusty quality.

If you are going to do a 100% water change I would probably get some bottled bacteria. That way you can add a capful to the filter. It isn't absolutely necessary, and is completely optional, but it won't hurt anything. I usually add a capful of Stability for any water changes over 60%. But I am paranoid about losing my cycle. Lol
 

Civanna

Yes it is safe to do it once in awhile. But I would try to solve the problem another way, First.

Do you have carbon in your filter? This will give your water a more sparkling appearance. It acts as a polish. So that may help. Also using filter floss will help get all those tiny particles out of your water.

Are you sure it isn't the film on the inside of your glass? It can make the water appear as if it has a dusty quality.

If you are going to do a 100% water change I would probably get some bottled bacteria. That way you can add a capful to the filter. It isn't absolutely necessary, and is completely optional, but it won't hurt anything. I usually add a capful of Stability for any water changes over 60%. But I am paranoid about losing my cycle. Lol

I do have carbon in my filter!

And omg what's filter floss? I need some ASAP!

Yeah it's those little particles in my precious water that drive me MAD!

I want it to be pristine like it was when it was first filled.
 

BottomDweller

It's safe but in this case unnecessary
 

Discusluv

I do have carbon in my filter!

And omg what's filter floss? I need some ASAP!

Yeah it's those little particles in my precious water that drive me MAD!

I want it to be pristine like it was when it was first filled.

If your water parameters are stable, ph within .4 and temperature within 2 degrees it is great for fish ( I would do 90% -not 100%- until the fish lay on their sides and circle)- there are no downsides. I have done this frequently in my years of raising discus, it may temporarily stress fish but the benefits of clean healthy water are ten-fold. Your fish will not die or succumb to illness due to these large water changes in either the short-term or the long-term if you are doing them correctly.
 

Civanna

If your water parameters are stable, ph within .4 and temperature within 2 degrees it is great for fish ( I would do 90% until the fish lay on their sides and circle)- there are no downsides. I have done this frequently in my years of raising discus, it may temporarily stress fish but the benefits of clean healthy water are ten-fold. Your fish will not die or succumb to illness due to these large water changes in either the short-term or the long-term if you are doing them correctly.

What does it mean if the fish lay on their sides & circle?
 

Discusluv

If your tank is set up for longer than six months, and you have not lost any of your bacteria to meds, etc... a 90% water change every once in a while will not make you lose your cycle. But, if it helps you psychologically, by all means use a bacterial supplement.
 

Nada Mucho

I don't agree that it's safe. You have to do something with your stock and that "something" entails risks. Fish that are dropped, stressed or shocked by the transfer. I feel that putting your stock through that kind of stress just so you can have less particles in your water is a bad trade off. However it's your tank and you can do what you like.. .just one opinion. Good luck either way.
 

Discusluv

What does it mean if the fish lay on their sides & circle?
Good question, that wouldn't be the case for all fish, my fish are between 7" and 5.5", when I do a 90% water change, they will lie on their sides because they are deep bodied, your fish may not need to do this if they are small with a 90% change.
 

Civanna

I don't agree that it's safe. You have to do something with your stock and that "something" entails risks. Fish that are dropped, stressed or shocked by the transfer. I feel that putting your stock through that kind of stress just so you can have less particles in your water is a bad trade off. However it's your tank and you can do what you like.. .just one opinion. Good luck either way.

The reason I asked the question is because I didn't know the answer. I'm still learning. If it's not safe, I'm not gonna do it.
Someone mentioned filter floss so I'll try that.
 

AllieSten

Filter floss is literally pillow stuffing you buy at the craft store. You can purchase the spendy aquarium stuff, but why? My bag cost $1.99 and I have replaced my floss every week in 3 tanks for the last 4 months and still have more than half a bag left. You want to be sure the filter floss is NOT treated with the fire retardant chemicals. It will say so right on the bag. Be sure to double check. You will just take a handful and stick it inside your filter.

If you look on YouTube it will show you exactly how to use it. But it is literally grabbing a handful of the batting and shoving it into your filter. Super easy.
 

Nada Mucho

The reason I asked the question is because I didn't know the answer. I'm still learning. If it's not safe, I'm not gonna do it.
Someone mentioned filter floss so I'll try that.

The reason I gave an answer is because you asked the question. Good luck.
 

AllieSten

Oh and you should be replacing your carbon once a month. So if it has been longer than that, it may be time for new carbon.
 

Civanna

Oh and you should be replacing your carbon once a month. So if it has been longer than that, it may be time for new carbon.

It's been 4. That's how long I've had these lil fishes. Is it dangerous to not change?
 

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