Anyone ever hear of nitrates dropping 90ppm in a day?

[Amnestia]

Yesterday night I did a run of tests on my tank (just finished cycling and such for a couple of weeks now). Did a 15% water change a few hours before I ran the tests. It's a 55gallon tank.

Salifert test kits
Phosphates 0
Ammonia 0
Nitrite 0
Nitrates 100ppm or more (tested it twice to be sure of the intensely dark purple color) NOTE Nitrates were also 100+ppm before the water change.
Temperature 78

Then 24 hours later (tonight) I tested nitrates again, it's down to about 10ppm, retested twice to be sure.

Anyone ever have this happen? I have a DSB running in my refugium for about 1.5 weeks now, it's 24"L x 12"W with 5-6" bed of sand. Also 120 or so lbs of live rock and 40lbs live sand in the main tank. The skimmer (Bermuda-3c) produced about 1/4th cup of wet skimmy since yesterday.

I find it hard to believe that the tank can process that much nitrate in a single day. Any thoughts?

 

[cbrownfish]

What kind of test kit are you using? I have to believe that the first sample was tainted or the test kit is simply bad and giving inconsistent results.

 

[BigAl07]

I have to agree with cbrownfish. Unless there is something happening we can't picture in our heads, there is no way for that to happen especially in a new/young system. Nitrates are reduced via water changes and they are in direct proportion to percentage of water change. In order to reduce your nitrates by 90% you'd have to change approximately 90% of your total tank volume and I wouldn't suggest that except for a MAJOR emergency.

Take your tank water to a LFS and have them run a whole series of tests to confirm/deny all of your test results.

Test kits are dated and do have a "Shelf Life". It's possible something is wrong with your test kit.

Good luck and I hope the 2nd test results are the ones that are accurate

Allen

 

[BigJay]

not unless you had the worlds worst cyano outbreak overnight. I've seen systems drop 20 points with cyano outbreak over a 24-48 hour period.

 

[Amnestia]

There is a 7x7 inch patch of diatoms that is growing on the deep sand bed?

The test kits are Salifert with expiration date for 06/10. I'm starting to think I somehow messed up the first batch of tests. I top off my water/supplement drip at night and I did switch from water store bought water(which turned out to be loaded with nitrates) to LFS ro/di water that same day.

Brought to LFS today to pickup some clowns and get water tested. Nitrates are indeed at ZERO!!! Looks like the 2nd test came out accurate.

Also bought a bag full of red gracilaria for my fuge and future tangs.