Question about Nitrates in Tank

[SaphireFire]

So I let my 30 gallon SW go, and the nitrates are literally through the roof. So, I'm trying to get back on the band wagon and get things going before I kill my last clown fish. Starting two days ago, I've done a 5 gallon water change each day (so two thus far), and my nitrates are literally not moving anywhere. They are simply not going down. My question is, how long/how many water changes does it take for your nitrates to start going down once they have sky-rocketed? Can I be doing bigger water changes to make this go faster? I'm sure my fish and Kenya tree don't like being in water so crappy.

Thanks for your help!

 

[major fish]

Most people will tell you to do a large water change and it will drop. However it won't make too much difference to the nitrate levels.

Removing nitrate is not relative to percentage of water removed. So a 40% change will not lower them by 40%.

Nitrate removal is logarithmic and this means that to reduce by water change alone, will have to be done by a method known as 'a stepped water change'.

Not too sure what links I can or can't put in here, but if you google 'stepped water change' or 'multiple stepped water change' the info will come up about how to do one and what considerations to take into account and look out for.

 

[ddelozier]

Multiple small water changes, and maybe introduction of some form of micro algae, either a display algae, or through a sump system. Chaeto is very effective at combating nitrates.

 

[PSU4ME]

Think of it as cleaning.......get the flow in the tank up, blow off the rocks with a turkey baster.......do a water change, remove the crap. Don't overfeed. How much Live rock to you have? Macro algae like chaeto will help but I assume, as you pointed out, that "letting the tank go" for a bit is the major culprit. Get her moving again and you shoudl start seeing differences.

 

[SaphireFire]

Its only been two days, I'm just very impatient I guess. I will pick up some macro algae when I go into town tomorrow, and I'll keep up with the water changes. Might do a "stepped water change" this weekend. Have cleaned off all my live rock, siphoned the crushed coral. Its looking so much better, but the nitrates still suck. All other parameters are OK, except the pH which is a little low (will be fixing that with chemicals).

Thanks for your input guys!

 

[major fish]

If you do stepped water changes that will bring it right down. keep an eye on the ph whilst doing them.

The only quick solution is water changes, by stepped method.

partial daily changes will take ages to lower them and algae will not be a quick fix.

 

[steved13]

Most people will tell you to do a large water change and it will drop. However it won't make too much difference to the nitrate levels.

Removing nitrate is not relative to percentage of water removed. So a 40% change will not lower them by 40%.

Nitrate removal is logarithmic and this means that to reduce by water change alone, will have to be done by a method known as 'a stepped water change'.

Not too sure what links I can or can't put in here, but if you google 'stepped water change' or 'multiple stepped water change' the info will come up about how to do one and what considerations to take into account and look out for.

Id like to see some explanation of this. Nitrate is measured in PPM if you start with 100ppm and remove half and replace it with 0ppm the result has to be 50ppm. This is simple arithmetic. I've never heard of any logarithmic formula.

Now if the nitrates are actually off the scale we have no idea where a 50% change should end up.

This is the only thing I could find ( i only did a quick search, I may have missed what you are referring to) about a stepped water change, and it makes no mention of any logarithm, and actually speaks to...a 50% water change reduce nitrates by 50%....the article mentions other numbers in a confusing way but that's what it amounts to.

Animated Graphic of Rapid Nitrate Reduction


I would start with a 50% water change and see where that leads you.

 

[ddelozier]

im confused too. volume based math(assuming the nitrates are evenly spread in the water, which they should be if there is modest+ Flow in the tank). 50% water change removes 50% of the nitrates in the tank if the water going in is RO/DI 0ds water made fresh into SW and the mix has no nitrates in it. That brings the total ppm to half what they were. do another 50% water change, and you are at 25% of the nitrates from before. do another and you are at 12.5%.

100
50
25
12.5ppm

the math says 3 water changes will make the water safe, 4 will make the water close to pristine till some form of export can be setup.

btw i call a small waterchange, anything 50% or less.

 

[major fish]

logarithmic as in a 50% change will not drop the nitrate by 50%, it will drop it by a smaller percentage. My LFS has been at it over 40 years so if he tells me it is logirithmic, it is lol. I know what he means by the use of the term and in the context it is conveyed.

If you have a 100 gallon tank with 60ppm nitrate and do a 50% water change then the nitrate will not drop to 30ppm.

you need to do repeated same percentage water changes over a period of time to bring it down or do stepped changes to get it down in a short space of time. both will work, one is quicker.

i normally do my levels before a water change but last week i did it before hand. 37 litre change on a 190 litre tank and nitrates dropped............virtually nil on the chuff chart but by colour of the test water, not too much in relation to the percentage of water changed out.

 

[major fish]

im confused too. volume based math(assuming the nitrates are evenly spread in the water, which they should be if there is modest+ Flow in the tank). 50% water change removes 50% of the nitrates in the tank if the water going in is RO/DI 0ds water made fresh into SW and the mix has no nitrates in it. That brings the total ppm to half what they were. do another 50% water change, and you are at 25% of the nitrates from before. do another and you are at 12.5%.

100
50
25
12.5ppm

the math says 3 water changes will make the water safe, 4 will make the water close to pristine till some form of export can be setup.

btw i call a small waterchange, anything 50% or less.

i know what you refer to by small water change now lol.

don't worry about the maths it doesn't work that way. i thought exactly the same thing.


In my LFS, nitrates have shot up. LFS advice, reactor. However I don't have a sump on that tank and am not whacking one on the floor.

I then think aloud to him.....big water change. Waste of time, it won't reduce it in proportion, trust me he says.

that is why I tested before last water change and after it. turned out he was right, it didn't impact the nitrate in direct proportion.

I also completely changed out the water and rinsed all media in one of my filters which are all oversized for the tank. i have plenty of flow too.

 

[major fish]

Might have had a brainstorm moment.

If you do a 50% water change then you do take 50% of the nitrate out but when you add the new water you dillute the remaining nitrate, hence why you will not get a reading of 50% less.

 

[lcstorc]

Where is Allen when I need him. He had a line in a signature that explained it. I'll see what I can find about the way the reduction works, but another thing to remember is that our fish and fish food are always adding to the bio-load/nitrates so some of what you take out is coming right back in.
I do remember from the math that a large water change will reduce them by more than several smaller water changes.

 

[TylerHaworth]

Oh, so if your LFS told you that putting bacon in your tank it would cause your Hogfish to incite an uprising you would believe that too, because he has 40 years of experience running a business?

My guess is that you don't understand what you're arguing.

Nitrate reduction is directly proportional to water change percentage. Period. Your/his logic defies both logic and the physical laws of our universe.The nitrates don't go into hiding when they see a water change bucket coming, lol.

Multiple water changes are logarithmic, but a single is not. 50% change is 50% reduction, however two 50% changes will be a 75% reduction from the original, a third will leave you with about 12.5% of the original, ad infinitum.

100 - 50 - 25 - 12.5 - 6.25 - 3.125

 

[steved13]

No it's simple arithmetic. I don't believe your LFS.

If it is a logarithm then what is it? A logarithm is fixed, so 50% gets you 5%...10%...25%...what does he say it is? What does he say a 50% water change reduce the nitrates by?

For what it's worth, it's simple arithmetic, but you do have to follow closely:

If I have 98 parts of water with 2 parts nitrate (2 part per hundred) if I remove half that leaves 49 parts water and 1 part nitrate (still 2 parts per hundred), I add 50 parts water I now have 99 parts water and 1 part nitrate (1 part per hundred)...I've gone from 2 parts per hundred to 1 part per hundred or 50% water change reduced the concentration by 50%.

Now unless you're testing with very good test gear, I'm not sure the color changes can tell you if you've reduced by half or not. I would trust the simple math above more than the test kit.

 

[steved13]

Nitrate reduction is directly proportional to water change percentage. Period. Your/his logic defies both logic and the physical laws of our universe.The nitrates don't go into hiding when they see a water change bucket coming, lol.

Multiple water changes are logarithmic, but a single is not. 50% change is 50% reduction, however two 50% changes will be a 75% reduction from the original, a third will leave you with about 12.5% of the original, ad infinitum.

100 - 50 - 25 - 12.5 - 6.25 - 3.125

Exactly, many people think "if I do 2 x 50% water changes that's 100%" and it doesn't work that way.

 

[steved13]

Where is Allen when I need him. He had a line in a signature that explained it. I'll see what I can find about the way the reduction works, but another thing to remember is that our fish and fish food are always adding to the bio-load/nitrates so some of what you take out is coming right back in.
I do remember from the math that a large water change will reduce them by more than several smaller water changes.

I found it for you Lynn
From Allen's signature:

Nitrate (NO3) reduction is directly proportional to percentage of Water Change.

 

[ddelozier]

I can understand where your LFS guy is trying to add complex math to something that isnt complex. If it was simple, he couldnt sell you a $150 Reactor to fix it. See, so it is complex math. He's trying to add to his bottom line, while you are trying to reduce your nitrates. That does equal a logritm. 50% water change reduces the physical amount of nitrates by 50% if its equally dispersed in the water collumn. I did fairly well in physics, and even better in chemistry. the entire reason we add flow to our tanks is to prevent a buildup of noxious chemicals in any given spot by spacing them out in the water column and moving them to where they can be processed. If you then add 50% sw without nitrates into the same space vacated, you still have 1/2 the amount of that chemical you started with, now dispersed into 2x as much water....its very simple 5th grade arithmetic. Now reducing the current amount of nitrates, and halting its production arent the same thing. The whole time you are doing water changes, the nitrate source is producing more. Thus why an export system is in place. If a stable system starts showing traces of nitrates or phosphates, it means quite simply that the measure being taken for the export of those two waste chemicals is not enough or something has changed and too muchis being added.

I mean no insult, so please dont take it that way. I ran a business for 7 years, and i know well the needs to add to the bottom line. If a customer asked me how they could obtain what i was selling more cheaply by bypassing me, I wouldnt tell them either. Its business

 

[major fish]

First thing first, my LFS don't sell things without reason to make a profit. A reactor was pointed out as a way forward whilst being told it was no quick fix, chemicals were also discussed as was the drawbacks and what could go wrong in using them. they advise and leave the decision to the customer.

First time I went there with the wife to get a tank, I walked out in disgust after 30 minutes and no service offered. I went back in after the wife explained that it was the same over 30 years ago when she used to go with her brother. If you want, then you ask but they aren't going to pester you.

Sometimes business is not all about profit in short term it is about business in the long term. mine has been going 24 years and i turn down contracts if they don't fit in with the standard of work that befits my company name, no matter what the profit is on them. Reputation breeds work and work breeds profit. Mind you it has been off and on whilst doing other work too, but when I pick it back up the response is over night.

I am not insulted by anyones remarks.....bit too old for that lol. It is what a forum is about...open discussion and different ways of thinking.

If you change 100% water in your display tank then you will still have nitrate and nobody has grasped the reason why. yet. because you are all concerned about maths and percentages.

extremely simple. 100% out of your tank still leaves a percentage of water in your filters or in your sump and this still has nitrate in it. what about the live rock in the tank and the sand. Will still contain nitrate, unless it is only water borne.

signatures are what they are. If I coin the correct phrase God is airborne, he couldn't pass the Royal Marines Commando Course. doesn't make it fact. Although it is very true, along with there is two types of marine in this world.....a submarine and a Royal Marine. ( thats for the Americans on here, you'll appreciate that one lol)

 

[steved13]

It's good that you trust your LFS, I have 1 that I trust very much also. It doesn't mean I can't misunderstand something they've said, nor does it mean they are 100% correct 100% of the time.

Your point about the water left behind, while is true in the way you phrased it, it has nothing to do with the points made above...a 50% water change is a 50% water change...if someone hasn't taken into account all factors properly then it wasn't a 50% water change, but whatever % it is will result in roughly the same percentage of nitrate reduction.

I am not in the group you describe as " because you are all concerned about maths and percentages" The math and percentages are for the benefit of others so that the process can be understood properly.

To say that a 50% water change won't reduce the concentration by 50% because it's a logarithm..just makes no sense, and flies in the face of the basic math. Had anyone said...hey don't forget about the water in the pumps and filters...then yes I would have to agree that may change the percentages...of both the water change and the nitrate reduction...however that has nothing to do with a logarithm.

I can't buy into this logarithm theory without more info to explain, why the simple math is wrong. So I guess we can agree to disagree.




The original post is asking "Can I be doing bigger water changes to make this go faster?"

The answer is yes as long as the pH and temp are appropriate. Some folks say dropping nitrate too fast can be detrimental. I've never seen this, someone may chime in who has with more info.

I'd recommend a 50% water change, see where that puts the numbers and then go from there.

 

[TylerHaworth]

extremely simple. 100% out of your tank still leaves a percentage of water in your filters or in your sump and this still has nitrate in it. what about the live rock in the tank and the sand. Will still contain nitrate, unless it is only water borne.

I literally lol'ed at that... You're still creating matter here... You can't take 100% away and have some left over...