water changes are not lowering nitrates

[Narwhal72]

This is an interesting post. And it brings up some fun mathematics to do.

Q2: Are 2 x 30% water changes the same as a 60% water change?
A: No, A single 60% water change will remove 9% more nitrate than 2 x 30% water changes. Reason being is that the second 30% water change is actually removing some water that was added to the aquarium after the first water change.

Q2: Which is better 2 x 30% per week or 1 x 60% per week?
A: As explained in question 1, a 60% is more efficient at lowering nitrate levels than the 2 x 30%. It is also more efficient in the longer term at lowering nitrate levels. However the 60% water change will result in higher levels of nitrate between water changes than the more frequent smaller water changes.

Example: Aquarium A receives 10ppm nitrate every day from food additions.
At 3 days the nitrate concentration is 30ppm at which point a 30% water change is done. This lowers nitrate to 21ppm. After 4 more days the nitrate is 61ppm and a second water change is done. This lowers the nitrate to 42.7 ppm. After 3 more days the nitrate is 72.7 ppm and another water change is done which lowers it to 50.89 ppm. After 4 more days another 30% water change is done and brings it to 63.62 ppm.
Aquarium B receives the same daily increase in nitrogen. After 7 days a 60% water change is done bringing the nitrate to 28ppm. After 7 more days a second water change is done bringing the nitrate at the end of 2 weeks to 39.2 ppm.

Q3: Why aren't the nitrate levels lowering?
A. There are many reasons for this. It can be an inaccurate test kit, it can also be insoluble nitrate becoming soluble again after the water change. It should also be pointed out that neither water change plan will actually lower the nitrate levels or even maintain them at the same level long term. All they do is slow down the rate of increase.

My advice is to do the 60% water change weekly. Nitrate levels of around 60 ppm are not that problematic and your fish and plants will readily adapt to it. I would not put so much time or worry into getting the nitrates down and just concentrate on keeping the tank stable as opposed to some specific chemical parameters.

Andy

 

[p0tluck]

There's no need to shake bottle #1. The instructions say to vigorously shake bottle #2 for 30sec, but I've seen where salts settle out in bottle #2 if not used in a long time, requiring some serious shaking.

Again, sorry if I missed it, but what is the nitrate reading for your tap water?

My API master test kit is ~3.5yrs/old, but I did replace the nitrate bottles a year or so ago given I used up the originals. API puts an expiration date on each bottle. It's somewhere around 4yrs from the date of manufacture.

I know what I would do to try to 'reset' your nitrates. Take the water right down to where your fish, decor, and plants can safely make it through, refill and then do it again. If your nitrates tube isn't still yellow at that point, something is up with your source water or kit.

my source water is 5 ppm, i will go test it again by shaking the #2 bottle like i did in my video i shake it for 1 min to make sure i get it stirred good , if you dont shake it and the sediments are at the bottom the reading will read 0 not high, as when i first started my nitrates read 0 and someone told me i had to shake bottle 2 hard which i did not know as i was just beginning so i did that and wam it was at 80 - 100 i have managed to get it to 60ppm but no lower , my bottles are not expired i checked them yesterday however they could of went bad from sitting. i will do a short video of my tap bottle shaking included lol.

 

[p0tluck]

There's no need to shake bottle #1. The instructions say to vigorously shake bottle #2 for 30sec, but I've seen where salts settle out in bottle #2 if not used in a long time, requiring some serious shaking.

Again, sorry if I missed it, but what is the nitrate reading for your tap water?

My API master test kit is ~3.5yrs/old, but I did replace the nitrate bottles a year or so ago given I used up the originals. API puts an expiration date on each bottle. It's somewhere around 4yrs from the date of manufacture.

I know what I would do to try to 'reset' your nitrates. Take the water right down to where your fish, decor, and plants can safely make it through, refill and then do it again. If your nitrates tube isn't still yellow at that point, something is up with your source water or kit.

my source water is 5 ppm, i will go test it again by shaking the #2 bottle like i did in my video i shake it for 1 min to make sure i get it stirred good , if you dont shake it and the sediments are at the bottom the reading will read 0 not high, as when i first started my nitrates read 0 and someone told me i had to shake bottle 2 hard which i did not know as i was just beginning so i did that and wam it was at 80 - 100 i have managed to get it to 60ppm but no lower , my bottles are not expired i checked them yesterday however they could of went bad from sitting. i will do a short video of my tap bottle shaking included lol.

This is an interesting post. And it brings up some fun mathematics to do.

Q2: Are 2 x 30% water changes the same as a 60% water change?
A: No, A single 60% water change will remove 9% more nitrate than 2 x 30% water changes. Reason being is that the second 30% water change is actually removing some water that was added to the aquarium after the first water change.

Q2: Which is better 2 x 30% per week or 1 x 60% per week?
A: As explained in question 1, a 60% is more efficient at lowering nitrate levels than the 2 x 30%. It is also more efficient in the longer term at lowering nitrate levels. However the 60% water change will result in higher levels of nitrate between water changes than the more frequent smaller water changes.

Example: Aquarium A receives 10ppm nitrate every day from food additions.
At 3 days the nitrate concentration is 30ppm at which point a 30% water change is done. This lowers nitrate to 21ppm. After 4 more days the nitrate is 61ppm and a second water change is done. This lowers the nitrate to 42.7 ppm. After 3 more days the nitrate is 72.7 ppm and another water change is done which lowers it to 50.89 ppm. After 4 more days another 30% water change is done and brings it to 63.62 ppm.
Aquarium B receives the same daily increase in nitrogen. After 7 days a 60% water change is done bringing the nitrate to 28ppm. After 7 more days a second water change is done bringing the nitrate at the end of 2 weeks to 39.2 ppm.

Q3: Why aren't the nitrate levels lowering?
A. There are many reasons for this. It can be an inaccurate test kit, it can also be insoluble nitrate becoming soluble again after the water change. It should also be pointed out that neither water change plan will actually lower the nitrate levels or even maintain them at the same level long term. All they do is slow down the rate of increase.

My advice is to do the 60% water change weekly. Nitrate levels of around 60 ppm are not that problematic and your fish and plants will readily adapt to it. I would not put so much time or worry into getting the nitrates down and just concentrate on keeping the tank stable as opposed to some specific chemical parameters.

Andy

i agree 100% on not being problematic nor high as people with full planted tanks dose 30-40 ppm weekly, however it does indeed bug me when every post i make people tell me i need to lower my nitrates to sub 40%, with my anxiety and how tedious and thorough i am with tank maintenance it has me over thinking things instead of just watching & observing to see if my fish have any ill affects , i used to do 1 50% weekly but i was advised its better to do as less as possible as it doesnt stress fish ass bad as doing 2 smaller ones rather than one larger one , i dont know how the exact details of why they mentioned 2 smaller is better than one bigger one something to do with taking so much water out at one time.

as far as my source i just did a test its not even 5 thats why i said its <5
my feedings are multiple small per day like 1/2 teaspoon 2 x a day so 1 teaspoon per day if i had to measure it that way its very small twice a day.

what else doesnt make sense is i run matrix and nitrazorb in my aquaclear 70 and bio chem sorb with ceramic media in my aquaclear 110

 

[p0tluck]

here is my test in full detail from start to finish .. brb need a heat pack for my shoulder lol

 

[tommy d]

another thing you can do is not hold the bottles at an angle when you are adding the drops. Hold the bottle straight down into the test tube and squeeze very slowly. An angled drop gives you much more chemical.....And yes...shake, shake, shake

 

[p0tluck]

another thing you can do is not hold the bottles at an angle when you are adding the drops. Hold the bottle straight down into the test tube and squeeze very slowly. An angled drop gives you much more chemical.....And yes...shake, shake, shake

yeah its all good man i was just trying to make sure the camera was facing the tube its usually straight up and down.

 

[Narwhal72]

I have grown to discover that the whole (smaller water changes doesn't stress fish) concept is a bunch of hooey. I know discus breeders that do nearly 100% water changes daily and never have problem. I have seen the fish laying flat on the bottom waiting for the tank to refill. If that isn't stress then I don't know what is. And yet the fish have no problem and will continue breeding and raising fry right after the change.

I think the problem is people that don't change water often and then suddenly doing a big water change. If you go 6 months without changing water and then do a big water change then yes, your fish are probably going to freak out from the sudden and massive change in water chemistry.

But if you are doing regular changes that aren't spread out by months then the stress on the fish is likely minimal.

 

[FreshyFresh]

^^^ This.

If fish have somehow been able to adapt themselves and survive horrible water conditions and then are subjected to a large water change, that's where the problems arise.

Like I've mentioned elsewhere, on my 75g that contains an oscar and a severum, I dump the water right down to where they are flopped over onto their sides. The two goofs just stay put giving me the stink-eye until the refill, during which they're all frisky and energized.

Regardless of the type of fish, there's no debating the fact that high nitrates will effect them badly over time. 40-60ppm certainly isn't horrendous, especially if you keep up on water changes, but the lower the better. I personally cannot decipher the 3 shades of orange well on the API master test kit for nitrates. I've just never kept a tank in the red.

 

[SnakeIce]

He does use root tabs. Most of the time they don't affect water column nutrient levels especially if undisturbed. Could be the source of the extra nitrate though.

 

[FreshyFresh]

He does use root tabs. Most of the time they don't affect water column nutrient levels especially if undisturbed. Could be the source of the extra nitrate though.

True, especially given he also vacuums and I assume stirs up the substrate some in the process. I don't gravel vac rooted plant tanks at all.