Should I Change My Water...or Leave It Alone?

Hi! I'm in Wk 10 of cycling my new 356 litre tank. All my water readings are perfect (ammonia 0, nitrate 0, nitrite 0, pH 7.3, temp 27.). The water is clean and sparkling. All my (35) fish seem happy and healthy and getting on together well - no bullying or fin nipping so far . I've read so much about the need for constant water changes - and there seems to be a lot of difference of opinion and controversy on the net about this issue - ranging from opinions like "I never, ever change my water - it's the filtering that's important" to "you must do a 50% water change at least once a week." My gut feeling is that if my water is perfect, all my fish are happy and the aquarium looks great, why mess with it? "If it ain't broke don't fix it!" May I throw this one out there and ask forum members their opinions about my situation? Should I change my water or not, and if so, how much and how often?

 

Obviously vacuuming the substrate is a must.

I am new to hobby myself but I personally let the water parameters dictate first and foremost. Secondly, strain or lift out any debris that is not caught by the filter.

Replenish the water removed when vacuuming the substrate and check the numbers.

Apologies for being a bit wordy.

 

I would ask what you are using to test with. Have all the fish been in there 10 weeks? As for my water change regiment I always do about a 20% weekly. Even if the Nitrates are low because minerals need to be replenished. That being said you definitely should be seeing some amount of Nitrates even in a heavily planted tank.

 

Obviously vacuuming the substrate is a must.

I am new to hobby myself but I personally let the water parameters dictate first and foremost. Secondly, strain or lift out any debris that is not caught by the filter.

Replenish the water removed when vacuuming the substrate and check the numbers.

Apologies for being a bit wordy.

Thanks for your advice Charlie's Dad. My coarse sand substrate looks very clean, so I think I will wait until there's visible signs of 'dirt' before vacumming. I have 4 Pepper Corys and a large (8cm?) Bristlenose, so perhaps they are doing the substrate cleaning for me?

I would ask what you are using to test with. Have all the fish been in there 10 weeks? As for my water change regiment I always do about a 20% weekly. Even if the Nitrates are low because minerals need to be replenished. That being said you definitely should be seeing some amount of Nitrates even in a heavily planted tank.

Hi! Thanks for reply. I gradually stocked my tank over a 10 week period. I initially filled it at the end of July, then when I had stabilised it I introduced 10 Neon Tetras. Eight days later came the Black Veil Tetras once my local aquarium shop had tested my water again for me, and confirmed all my parameters were good. I've been introducing more fish every week or so since then. I'm using ApI test kits - all brand new - and the first time I tested I took the same water samples to my aquarium shop, and they got the same results as me, so I'm fairly confident that my testing is correct. My tank doesn't have real plants - this is what it looks like.

So you think I should do a 20% water change in Week 11?

 

If using the apI liquid kit when testing for nitrate you really got to shake bottle number two. I mean shake the immortal life out of it. The reagents in that bottle have a tendency to crystallize when sitting. If you are using the apI test strips throw them away and but a different brand. Especially since you have no live plants there is definitely Nitrates in that tank. The only ways we have of removing Nitrates are through water changes or live plants processing them out. I would definitely encourage you to look up some videos on the Nitrogen cycle on YouTube.

 

It doesn't sound like your cycled if you don't have plive plants. The only way you shouod see 0 across the board is if you have enough live plants to use the ammonia before the bacteria can.

As for water changes I would still do partial about 20% every week to replenish minerals and to remove disolved protiens and organics from your tank.

 

99% of nitrate mis readings with the apI test kit say zero.
It is as stated because reagent bottle number two has not been shaken enough.
An 11 week old stocked tank with fake plants could not have zero nitrates with only 20% water changes...At least not without ammonia or nitrites ?
Once again another reason to skeptical of having the people that sell you fish test your water IMO..

 

50% water change is too much for me. 25% once a week is a must. If I didn't the nitrates would be too high. I test before each water change and they always rise by the end of the week. After each water change there's a huge improvement. Why do a water change you ask? Because your fish pee and poo in that water. That's why!

 

I really like how you have aquascaped your tank! Very very nice.....

 

That definitely looks like a fun tank!

 

Lovely tank! And great question.

I don't think there is any one size fits all minimum water change schedule. How much and how often generally comes down to a number of factors, including how heavily stocked the tank is, what it is stocked with, how much filtration you have, and how much you feed. Live plants can help with water quality as well. It's a closed system so any changes to it will impact it, but over time and as it matures you can get to know what works best for your particular tank.

I have 9 tanks from 10G to 55G and over time I've been able to stop testing as much and just do regular changes. I know my 10G with a single betta, heavy filtration, and lots of plants might make it longer between water changes but I have found all my fish generally more active if I do them regularly -- and honestly, it takes as long to test and shake the dang nitrate test as it would to just change 25-30% of the water so I just do them weekly. My one 29G tank with panda corys (among others), planted with a so-called 50 gallon filter plus a sponge filter rated for 50 gallons, I still do 25% about twice a week because the pandas are sensitive to water quality. The 55 is very lightly stocked and very heavily planted/over filtered so I can do that one about every 8 days. It's a bother to remember that, so I do that one with all the others -- happy water change day!

If you have a pleco there is no way your nitrates are at zero but you are pretty lightly stocked, so they could be reasonably low. BTW, plecos and corys don't "clean" the substrate of anything but uneaten food. Poop's gotta get vacuumed, and unless you have some serious powerheads moving your detritus around for the filter to pick up, you might be utterly shocked at what you find under the decor if you move it, lol. I'd rather vac the substrate than have my filters become nitrate factories by being overloaded quickly (I also have sponges over my intakes for the same reason and clean them weekly).

Not sure what all your 35 fish are (are they big fish, little fish?) but you can't go wrong with 20-25% weekly, especially with no live plants. Your fishies will thank you!

 

If using the apI liquid kit when testing for nitrate you really got to shake bottle number two. I mean shake the immortal life out of it. The reagents in that bottle have a tendency to crystallize when sitting. If you are using the apI test strips throw them away and but a different brand. Especially since you have no live plants there is definitely Nitrates in that tank. The only ways we have of removing Nitrates are through water changes or live plants processing them out. I would definitely encourage you to look up some videos on the Nitrogen cycle on YouTube.

Ah, OK, I'll shake the heck out of my No. 2 bottle and then re-test. Thanks for the advice! I may post my test colours just to get advice that I'm reading them correctly...although the difference will be minimal! Many thanks for your reply.

 

Lovely tank! And great question.

I don't think there is any one size fits all minimum water change schedule. How much and how often generally comes down to a number of factors, including how heavily stocked the tank is, what it is stocked with, how much filtration you have, and how much you feed. Live plants can help with water quality as well. It's a closed system so any changes to it will impact it, but over time and as it matures you can get to know what works best for your particular tank.

I have 9 tanks from 10G to 55G and over time I've been able to stop testing as much and just do regular changes. I know my 10G with a single betta, heavy filtration, and lots of plants might make it longer between water changes but I have found all my fish generally more active if I do them regularly -- and honestly, it takes as long to test and shake the dang nitrate test as it would to just change 25-30% of the water so I just do them weekly. My one 29G tank with panda corys (among others), planted with a so-called 50 gallon filter plus a sponge filter rated for 50 gallons, I still do 25% about twice a week because the pandas are sensitive to water quality. The 55 is very lightly stocked and very heavily planted/over filtered so I can do that one about every 8 days. It's a bother to remember that, so I do that one with all the others -- happy water change day!

If you have a pleco there is no way your nitrates are at zero but you are pretty lightly stocked, so they could be reasonably low. BTW, plecos and corys don't "clean" the substrate of anything but uneaten food. Poop's gotta get vacuumed, and unless you have some serious powerheads moving your detritus around for the filter to pick up, you might be utterly shocked at what you find under the decor if you move it, lol. I'd rather vac the substrate than have my filters become nitrate factories by being overloaded quickly (I also have sponges over my intakes for the same reason and clean them weekly).

Not sure what all your 35 fish are (are they big fish, little fish?) but you can't go wrong with 20-25% weekly, especially with no live plants. Your fishies will thank you!

Thanks for your detailed reply! If you are interested in all my aquarium details I have listed them in the profile section - but basically all my fish are juveniles except my female bristlenose, which is about 8cm. I think I agree that there's no 'one size fits all' answer to water changes - but as my tank is fairly lightly stocked, I have a 'bigger than necessary' external filter (which I've amended to be even more efficient...) and I've fed my fish lightly whilst cycling it, I think these factors account for my good water quality so far. But I do take your point about there will be lots of poop around - so I will do a water change shortly. And thanks for your compliment about my tank!

The 'Great Wall of China' came with my tank (I bought the whole set-up from an experienced guy...) and at first I thought it was a bit 'kitch.' But - it's actually very practical, because the 'wall' is hollow, and forms a long tunnel, with multiple entrances and exits through all the 'turrets' and windows. It provides so much safe hiding space for shy fish, and plenty of surface area for the corys to clean - which keeps them well occupied! I am thinking of introducing some real plants once my whole tank has settled...I'll post more pics when I change things around!

Thanks again for your help and advice.

I really like how you have aquascaped your tank! Very very nice.....

Thank you so much for your kind words...and good advice too.

50% water change is too much for me. 25% once a week is a must. If I didn't the nitrates would be too high. I test before each water change and they always rise by the end of the week. After each water change there's a huge improvement. Why do a water change you ask? Because your fish pee and poo in that water. That's why!

I take your point - and I think I will do a water change shortly...thanks for your advice.

 

99% of nitrate mis readings with the apI test kit say zero.
It is as stated because reagent bottle number two has not been shaken enough.
An 11 week old stocked tank with fake plants could not have zero nitrates with only 20% water changes...At least not without ammonia or nitrites ?
Once again another reason to skeptical of having the people that sell you fish test your water IMO..

I have used a shop called Marine Plus Aquariums for all my advice and purchases of fish and food. They are salt water specialists who have an incredible range of live corals and living reefs - but they also do freshwater. They have a really good reputation in my area, and the shop is run by a lovely couple in their late 50's who have kept fish for decades...!

Although I didn't buy my aquarium from them, they gave me detailed week by week instructions on how to cycle it, and when I went in with about my 5th water sample, which they test for free, and said: "Please can I put some neon tetras in now?" - they said - "No! Sorry, you'll have to wait another week or so...there's still too much ammonia...be patient..." So they actually turned down a sale as they wanted to do the right thing by me and the fish...

I've also got my water tested by a second shop just to triple-check my results - not that I'm cynical, but I am thorough and wanted to be sure that I am getting correct advice. All three sources gave the same results from the same water (my own brand new test kits, plus two shop tests) so I'm quite confident in the accuracy of my test results.

Thanks for the advice - there's nothing wrong with being skeptical (until trust is established I suppose!).

 

I have used a shop called Marine Plus Aquariums for all my advice and purchases of fish and food. They are salt water specialists who have an incredible range of live corals and living reefs - but they also do freshwater. They have a really good reputation in my area, and the shop is run by a lovely couple in their late 50's who have kept fish for decades...!

Although I didn't buy my aquarium from them, they gave me detailed week by week instructions on how to cycle it, and when I went in with about my 5th water sample, which they test for free, and said: "Please can I put some neon tetras in now?" - they said - "No! Sorry, you'll have to wait another week or so...there's still too much ammonia...be patient..." So they actually turned down a sale as they wanted to do the right thing by me and the fish...

I've also got my water tested by a second shop just to triple-check my results - not that I'm cynical, but I am thorough and wanted to be sure that I am getting correct advice. All three sources gave the same results from the same water (my own brand new test kits, plus two shop tests) so I'm quite confident in the accuracy of my test results.

Thanks for the advice - there's nothing wrong with being skeptical (until trust is established I suppose!).

 

I have used a shop called Marine Plus Aquariums for all my advice and purchases of fish and food. They are salt water specialists who have an incredible range of live corals and living reefs - but they also do freshwater. They have a really good reputation in my area, and the shop is run by a lovely couple in their late 50's who have kept fish for decades...!

Although I didn't buy my aquarium from them, they gave me detailed week by week instructions on how to cycle it, and when I went in with about my 5th water sample, which they test for free, and said: "Please can I put some neon tetras in now?" - they said - "No! Sorry, you'll have to wait another week or so...there's still too much ammonia...be patient..." So they actually turned down a sale as they wanted to do the right thing by me and the fish...

I've also got my water tested by a second shop just to triple-check my results - not that I'm cynical, but I am thorough and wanted to be sure that I am getting correct advice. All three sources gave the same results from the same water (my own brand new test kits, plus two shop tests) so I'm quite confident in the accuracy of my test results.

Thanks for the advice - there's nothing wrong with being skeptical (until trust is established I suppose!).

Update - 4 hours later! I tested my water again, showed no nitrates (pale yellow water). So then I shook the **** out of my reagent bottles for about 3 minutes - and tested again. This time the water went a deep orange. So then I tested for ammonia, nitrites and ph having thoroughly shaken all my test bottles. It showed my pH was a little too high (about 7.6, usually about 7.4), a little ammonia and some nitrites. Just to be convinced, I took a water sample to my aquarium shop, and they confirmed nitrates at about 20-30ppm. So I immediately did a 25% water change.

So, you've taught me a very valuable lesson ie. shake reagent bottles really thoroughly...and I will do another 20% or so water change in a couple of days. Thank you! Your advice was really valuable. Much appreciated!