Nitrate/Phosphate Issue

[mcgyvr]

You might want to cut back on the attitude a bit there...
OR at least ask someone close for a hug.. You seem to be a bit short tempered here in your responses and as a new member asking for help thats not the best plan..
We are all just trying to help and sorry we aren't really taking it as serious as you seem to be.. Its a minor issue and fairly normal occurrence..

Its not to uncommon at all for some people to perform water changes and see little/no change in the nitrate levels.
For the most part the reason for that is unknown really..

One comment about testing in general....after doing a water change the new water has not had time to mix and dilute the existing water so you could be sampling from areas of not fully diluted areas thus measuring the same value..
With testing you should always wait a good 30 minutes or more before taking another sample to allow the new water to fully mix with the old water..

But again.. Some tanks just seem to get stuck at a certain nutrient level and we really don't have enough scientific date to tell you why..
Sorry if that answer isn't acceptable to you..

[nereefpat]

Originally Posted by WGT1014

ok, then by your "math", my nitrates should go from 16 to 12 with a 20 gallon water change. then why is it that after a month of being at 16 and still doing 20 gallon water changes weekly, I'm still at 16? What my tank "produces" does not matter here because as I said a few posts back, I check nitrate before and after the water changes...it's not user error as it's always the same color...If I'm reading it wrong, so be it BUT with each water change the color should get lighter and it's not...

Why is math in quotes? Are you implying that my calculations are wrong?

The difference is going to be small, and like I said, you won't be able to tell the difference. All aquarium nitrate test kits are color comparison kits. The kit doesn't give you a number as a result; it gives you a shade of pink that you have to interpret. 12 or 16 won't be distinguishable unless you were to use a spectrophotometer that you made a standard curve for.

I see this kit has a low range side. Perhaps, if you have the equipment and skills, you could make dilutions and use the low range to see if you can tell a difference.

Have you tested a freshly made batch of saltwater yet? Is it zero?

[reefgeezer]

You might be trying to see changes that are outside the kit's accuracy. I looked up a You Tube on the kit and it seems very good. BUT hobby grade test kits just aren't that accurate or repeatable. Don't confuse "accuracy" with "resolution". You may be able to identify color differences to very small numbers but that doesn't mean the kit's chemistry has the capability to actually produce measurements to those numbers... particularly at low levels.

Once you get below 20 ppm of nitrate you might need to do larger water changes (50%) to see a change. I might also suggest that fussing over exact numbers isn't productive. Look at trends.

[WGT1014]

Originally Posted by mcgyvr

You might want to cut back on the attitude a bit there...
OR at least ask someone close for a hug.. You seem to be a bit short tempered here in your responses and as a new member asking for help thats not the best plan..
We are all just trying to help and sorry we aren't really taking it as serious as you seem to be.. Its a minor issue and fairly normal occurrence..

Its not to uncommon at all for some people to perform water changes and see little/no change in the nitrate levels.
For the most part the reason for that is unknown really..

One comment about testing in general....after doing a water change the new water has not had time to mix and dilute the existing water so you could be sampling from areas of not fully diluted areas thus measuring the same value..
With testing you should always wait a good 30 minutes or more before taking another sample to allow the new water to fully mix with the old water..

But again.. Some tanks just seem to get stuck at a certain nutrient level and we really don't have enough scientific date to tell you why..
Sorry if that answer isn't acceptable to you..

Not stopping my attitude. I like it and that particular line of thinking will end there...Now, why didn't you say this to begin with? I'm not asking for help, merely asking for possible reasons why I'm experiencing something...being a "new member" as you say, doesn't really explain why I had so many answers unrelated to what I asked...I don't buy the 30 minute rule you mentioned...maybe I type too fast

[WGT1014]

Originally Posted by nereefpat

Why is math in quotes? Are you implying that my calculations are wrong?

The difference is going to be small, and like I said, you won't be able to tell the difference. All aquarium nitrate test kits are color comparison kits. The kit doesn't give you a number as a result; it gives you a shade of pink that you have to interpret. 12 or 16 won't be distinguishable unless you were to use a spectrophotometer that you made a standard curve for.

I see this kit has a low range side. Perhaps, if you have the equipment and skills, you could make dilutions and use the low range to see if you can tell a difference.

Have you tested a freshly made batch of saltwater yet? Is it zero?

What I'm IMPLYING is your "math" in no way is helping with what I asked about...good for you, you can deal with numbers! That means nothing to me...did not help with what I asked...sorry, gonna have to get your cookie from another member this time around...

[WGT1014]

Originally Posted by reefgeezer

You might be trying to see changes that are outside the kit's accuracy. I looked up a You Tube on the kit and it seems very good. BUT hobby grade test kits just aren't that accurate or repeatable. Don't confuse "accuracy" with "resolution". You may be able to identify color differences to very small numbers but that doesn't mean the kit's chemistry has the capability to actually produce measurements to those numbers... particularly at low levels.

Once you get below 20 ppm of nitrate you might need to do larger water changes (50%) to see a change. I might also suggest that fussing over exact numbers isn't productive. Look at trends.

Ok, this seems plausible but then how come people can use this kit and see changes down to less than 1.0? I do agree that fussing over EXACT numbers isnt productive. But I should see a difference in the color between 16 and 12, for example...thank you for the reply...maybe it's the test kit I'm using...very possible it's bad, I suppose...

[nereefpat]

Rock and sand can bind things like phosphate and some metals, making removal and testing difficult.

This isn't the case for nitrates. Removing nitrates by water changes is simple math. 50% water change will reduce nitrates by 50%.

If you aren't seeing this, then there are only two possibilities:
1. Nitrates in your make up water
2. Limitations or error of testing.

Both can be tested. Test your make up saltwater. And do a bigger water change to see a bigger difference.

[WGT1014]

Originally Posted by nereefpat

Rock and sand can bind things like phosphate and some metals, making removal and testing difficult.

This isn't the case for nitrates. Removing nitrates by water changes is simple math. 50% water change will reduce nitrates by 50%.

If you aren't seeing this, then there are only two possibilities:
1. Nitrates in your make up water
2. Limitations or error of testing.

Both can be tested. Test your make up saltwater. And do a bigger water change to see a bigger difference.

Now that's a related answer...thanks...nitrates in my w/c water was also mentioned by Lapin...I'll be doing a water change tomorrow and I will check this out. Testing errors are possible but I do the test the same way every time and the color stays the same...As far as test kit limitations, I don't think that's it. I use Red Sea Pro and I'm still doing the high range test because apparently anything over 4.0 nitrates needs to be read with the high range test. Hmmm, is it possible that maybe I should do the normal test? Maybe my issue is from just automatically doing the high range test? You've given me something to think about...