Water changes - what is "normal"?

[Byron]

Personally, I think you have to balance nitrates and kH. Do a water change if nitrates are over 20 (not possible for those wirh nitrate in the water though) or do a water change when kH drops to avoid a pH swing. I normally do 10% a month for my tanks, but they're essentially filterless still ponds, except for the goldfish one, lol.

Waiting until some test shows a problem is not a good way to maintain an aquarium. That is why several of us are recommending significant weekly (regular) water changes; this actual stabilizes the biological system preventing such issues, and prevention is always preferable to reaction.

If nitrate is only occurring within the tank (not in the source water) and it is say 10 ppm, and by the end of a week or two weeks it has risen, you have a problem. This does affect the fish. Yes, they will usually live through it (some species would not), but that does not mean they are not being impacted; they are. My nitrate is in the 0 to 5 ppm range in all my eight tanks, and it never rises and hasn't for over 20 years now. I don't test it often because I know there is no need; when I do it is always in this range. And I always test prior to the weekly water change so I see what occurs over the seven days since the last. Same with pH.

If KH is an issue, and assuming you have fish that this impacts, then you need to be doing something permanent to buffer the GH and KH. The KH in all my tanks is zero and always has been, but I have wild caught soft water fish that need zero GH and an acidic pH. I have never had pH issues either, though it stabilizes at different levels in different tanks. Maintaining fish requiring harder water and a basic pH above 7 is a different story.

 

[FishGuest5123]

I am so jealous of those of you that can keep your nitrates so low. The goldfish are always high by week end but I even have to do w/c’s everyday on my bettas. The tropical tank is my best with neon tetras, guppies, and platies. None are overstocked and I have cut way back on my feeding. Nothing helps. Ammmonia and nitrites are fine but nitrates always climb. Several of the tanks are well over a year to 2 years old. I have plants and pothos in all the tanks but of course the goldfish pull most of theirs up. Any other ideas?

 

[Cichlid4life]

A lot of people only change 25% a week and believe you risk cycle issues if you do anymore. I don’t see how on an established tank. On another forum I hear this quite often. However, I agree with Colin_T that it’s better to do a larger one, at least 50% to 75%.

i do a 30-45% WC every week.

 

[Byron]

I am so jealous of those of you that can keep your nitrates so low. The goldfish are always high by week end but I even have to do w/c’s everyday on my bettas. The tropical tank is my best with neon tetras, guppies, and platies. None are overstocked and I have cut way back on my feeding. Nothing helps. Ammmonia and nitrites are fine but nitrates always climb. Several of the tanks are well over a year to 2 years old. I have plants and pothos in all the tanks but of course the goldfish pull most of theirs up. Any other ideas?

I assume by "fine" the ammonia and nitrite is always zero.

"Pothos" are the tropical house plants? Are the roots in the aquarium? These are poisonous plants.

Goldfish are large waste machines so this is going to work against you unless they are in a very large tank.

Aquatic plants do not use much in the way of nitrates. Most species prefer ammonium as their form of nitrogen, and they can assimilate a great deal. This has the benefit of not producing nitrite, or then nitrate, so that helps. But high organics will still cause higher nitrates. I had this in my 90g and could not figure out why. But there were for some reason higher organics in this tank than any of the others, even though very heavily planted and the surface thick with Water Sprite, and nitrate ran at 10 ppm. It happens, and it can be seasonal too.

 

[FishGuest5123]

I don’t believe pothos are poisonous as many aquarist userhem to control nitrates. I’ll certainly look into it again though but they’vebeen In one over 2 years. My tank is a 55G with 3 goldies and a 29G with 2. The 29g ones are moving to a 45G as they have grown way too big. Even when they were tiny I still had nitrate issues. Just tested my Goldie’s and at 80 after a complete tank cleaning 3 days s ago. Going to do a water change. Thank God for my Python!

 

[FishGuest5123]

I don’t believe pothos are poisonous as many aquarist userhem to control nitrates. I’ll certainly look into it again though but they’vebeen In one over 2 years. My tank is a 55G with 3 goldies and a 29G with 2. The 29g ones are moving to a 45G as they have grown way too big. Even when they were tiny I still had nitrate issues. Just tested my Goldie’s and at 80 after a complete tank cleaning 3 days s ago. Going to do a water change. Thank God for my Python!

I assume by "fine" the ammonia and nitrite is always zero.

"Pothos" are the tropical house plants? Are the roots in the aquarium? These are poisonous plants.

Goldfish are large waste machines so this is going to work against you unless they are in a very large tank.

Aquatic plants do not use much in the way of nitrates. Most species prefer ammonium as their form of nitrogen, and they can assimilate a great deal. This has the benefit of not producing nitrite, or then nitrate, so that helps. But high organics will still cause higher nitrates. I had this in my 90g and could not figure out why. But there were for some reason higher organics in this tank than any of the others, even though very heavily planted and the surface thick with Water Sprite, and nitrate ran at 10 ppm. It happens, and it can be seasonal too.

Ok, I checked again to be sure. Here’s what I found on Pothos... The Pothos vine will spread around the room, often dropping roots in other aquaria. Sometimes the roots can form quite a thicket in an aquarium, providing cover for small fish and a spawning substrate. Pothos are not poisonous to fish. Many people use them in terrariums with partial water, which fish inhabit.

 

[Byron]

OK, that may be a different plant from what I thought was Pothos. I found this earlier:

Are Pothos Plants Poisonous? While pothos plants are an easy to care for houseplant, you do need to be aware that they are poisonous. Though rarely fatal, the plant can cause irritation and vomiting if ingested due to the fact that it contains calcium oxalates. Even the sap from the plant may cause highly sensitive people to break out in a rash. It is considered toxic to cats, dogs and children, but as mentioned, it normally will make them very sick but will not kill them.

Read more at Gardening Know How: Information On Caring For Pothos Plants https://www.gardeningknowhow.com/houseplants/pothos/pothos-plant-care.htm

 

[Rtessy]

Waiting until some test shows a problem is not a good way to maintain an aquarium. That is why several of us are recommending significant weekly (regular) water changes; this actual stabilizes the biological system preventing such issues, and prevention is always preferable to reaction.

If nitrate is only occurring within the tank (not in the source water) and it is say 10 ppm, and by the end of a week or two weeks it has risen, you have a problem. This does affect the fish. Yes, they will usually live through it (some species would not), but that does not mean they are not being impacted; they are. My nitrate is in the 0 to 5 ppm range in all my eight tanks, and it never rises and hasn't for over 20 years now. I don't test it often because I know there is no need; when I do it is always in this range. And I always test prior to the weekly water change so I see what occurs over the seven days since the last. Same with pH.

If KH is an issue, and assuming you have fish that this impacts, then you need to be doing something permanent to buffer the GH and KH. The KH in all my tanks is zero and always has been, but I have wild caught soft water fish that need zero GH and an acidic pH. I have never had pH issues either, though it stabilizes at different levels in different tanks. Maintaining fish requiring harder water and a basic pH above 7 is a different story.

I don't wait till tests show a problem; I never get problems. All my tanks are 0/0/0 (the goldfish one was for nearly 7 months, recently got some nitrates). My tap water is essentially RO, 30TDS, 0kH. None at all! I was dealing with pH swing at first, one day 6.6, the next below 6 (luckily during fishless cycling). Took me a while to figure out the role that kH plays in pH, and how no buffering capacity is bad, lol.
I too have wild caught soft water fish, and normally I don't test my tanks, again, because I just haven't experienced problems. Actually, out of my 30+ fish, only two aren't softwater, not counting inverts. Gotta pick what matches your water, waaay easier than buffering the water every time, trust me!
Do my methods work for most? No, but my fish are healthy and happy, and part of the reason I do small changes is for my buffered tanks (shrimp) since my low TDS makes it nearly impossible to do large wstee changes if I have to keep it above 150 for my shrimp.
I wasn't trying to argue that nitrates, in any capacity, are good for fish, as it is my opinion that any amount of nitrates are harmful, since most water ways won't have any nitrates in them. IMO, 99% of aquarists don't have fully cycled tanks. The cycle is only truly completed once nitrates are converted back to nitrogen gas.
20 years is a long time to be in the hobby, I'm glad you were able to continue so long! Congrats!

 

[FishGuest5123]

OK, that may be a different plant from what I thought was Pothos. I found this earlier:

Are Pothos Plants Poisonous? While pothos plants are an easy to care for houseplant, you do need to be aware that they are poisonous. Though rarely fatal, the plant can cause irritation and vomiting if ingested due to the fact that it contains calcium oxalates. Even the sap from the plant may cause highly sensitive people to break out in a rash. It is considered toxic to cats, dogs and children, but as mentioned, it normally will make them very sick but will not kill them.

Read more at Gardening Know How: Information On Caring For Pothos Plants https://www.gardeningknowhow.com/houseplants/pothos/pothos-plant-care.htm

You’re correct. You should keep them away from children and dogs.

 

[sparkyjf]

if your nitrates are that high, how come your fish aren't dead? what kind of test kit are you using? teststrips are not accurate and liquid test always are if you follow the directions.

I think it's fair to say their life expectancy is nothing like it should be, even though they do live on. I'm using a liquid test kit from API, which I believe to be ok but open to comments on that

 

[sparkyjf]

What is your nitrate reading out of the tap? Its worth checking. Mine is 50 ppm and for years I did everything to avoid it ever going higher. The fish all "appeared" fine but I suspect their life expectancy was reduced. For the last year or so I have been actively reducing nitrates before adding the water to my tank. Of course its much too early to tell the long term effect on my fish - but I feel better for doing it.

Do you know, I never thought to check that - I just automatically assumed the starting level would be low. Now that you've said, I'll test and report back. I should have thought of that!

 

[sparkyjf]

Thank you everyone for your really informative and helpful comments - I'm really glad to have joined this forum! In answer to a few of the questions I've been asked (I'll try and address all of them but if I've missed anything forgive me):

Nitrate level at the end of 1 week after 50% water change is somewhere in the region of 80-160ppm (the two colour bands indicated at top of end of my API liquid test kit). I have not thought to measure the starting level, or the tap water level so will get this done.

Life expectancy of the fish is generally poor hence my question. I've established now that I need to do a water change at least weekly, and am now doing more like 75% every week. I do a gravel vac too which seems to be a big help.

I think my originating question was simply - is it expected to have to change the water weekly, but it seems conclusive to me that you do - in fact for some people more often than that! It sounds like I have a couple of things to go away and measure (latent nitrate level in tap water, start of week levels).

Week end Ammonia levels are showing around 0.25ppm, and 0.25ppm for Nitrite as well - they're not quite zero, but they are the lowest distinguishable level I can read on the test kit. I presume this is ok?

I've had problems with biological waste/microorganisms in the tank before which have caused problems but more thorough cleaning has solved that one.

On my Welcome thread, someone recommended a pump to help with the cleaning process. What does everyone use? I have a little hand pump that relies mostly on gravity (i.e. a siphon) but again wonder if there's something better that would make the job easier?

Thanks again everyone!

 

[NickAu]

I wouldn't have Pothos with plant eaters and I probably wouldn't want my Betta chomping on the roots.

Yes my Betta eats plant roots.

 

[seangee]

Do you know, I never thought to check that - I just automatically assumed the starting level would be low. Now that you've said, I'll test and report back. I should have thought of that!

If your tap water is much lower than your tank don't try to fix out all at once as that could send your fish into shock. This is one case where a series of 10 or 20% changes is better than a big change because, strange as it seems, your fish actually need to acclimate to clean water.

 

[Cichlid4life]

a lot of photos plant species, some could be safe and others not, who knows?