Rapid drop in nitrates

[ATXreefer]

A little background on the situation; My 29 gallon tank finished cycling about three weeks ago (fishless cycle), at which point I added 2 YWG, pistol shrimp, couple trochus snails and a mountain of red ogo. A week later, I added a pair of clowns and a handful of hermit crabs. I started testing nitrates every other day and they started above 50ppm the first day I added the ogo and first round of livestock. My nitrates were coming down consistently with weekly 25% water changes and presumably from the ogo consuming a good bit of it. In the last week, my nitrates went from about 25ppm to undetectable (using salifert nitrate test). I feed a moderate amount twice daily of mysis and PE pellets. Does this rapid drop in nitrates seem possible given the variables I shared? I tested twice just to make sure. Will be adding coral soon and am happy with low nitrates, but want to make sure this drop in nutrients is ok. Should I feed more to get numbers up slightly?

Thanks for chiming in.

 

[ATXreefer]

Apologies for the crap picture. Just wanted to try to give an idea of how much ogo is in the tank.

 

[Azedenkae]

A little background on the situation; My 29 gallon tank finished cycling about three weeks ago (fishless cycle), at which point I added 2 YWG, pistol shrimp, couple trochus snails and a mountain of red ogo. A week later, I added a pair of clowns and a handful of hermit crabs. I started testing nitrates every other day and they started above 50ppm the first day I added the ogo and first round of livestock. My nitrates were coming down consistently with weekly 25% water changes and presumably from the ogo consuming a good bit of it. In the last week, my nitrates went from about 25ppm to undetectable (using salifert nitrate test). I feed a moderate amount twice daily of mysis and PE pellets. Does this rapid drop in nitrates seem possible given the variables I shared? I tested twice just to make sure. Will be adding coral soon and am happy with low nitrates, but want to make sure this drop in nutrients is ok. Should I feed more to get numbers up slightly?

Thanks for chiming in.

Three things.

1. If there were any nitrites before, it could have caused the readings to be higher than expected. So if nitrite plateaus, your nitrates might suddenly just read wayyy lower.
2. When nitrates start to be consumed, they start to be consumed fast.
3. It is hard to say re: needing to feed more or not. The thing is, a lot of people will target some degree of measurable nitrate (with corals already in) to make sure there is enough nitrates for the corals. However, depending on the consumption rate, this may never happen. I have a 20 gallon tank and I feed a lot. Between 60 to 100 NLS regular sized pellets a day. Nitrates still read 0. Corals still look great and are growing great. It is just because my algae system consumes nitrates so well that yeah, I just can't register any nitrate, despite everything's fine. So yeah, conclusion is hard to say. Or more exactly, 'it depends'. XD

 

[ATXreefer]

Appreciate the response. I can confirm I have not tested for nitrites ever, so that may be the case. This is a good excuse to trim back some of the excess ogo that doesn't look so pretty!

 

[Randy Holmes-Farley]

Following up on the nitrite discussion, the rapid drop in "nitrate" might (25 ppm) have just been a small drop in nitrite. Say, 0.25 ppm to 0. Nitrite interferes with nitrate testing.

 

[ATXreefer]

Do you find it odd that the tank is developing GHA and other algae with such low nutrient levels? Especially since the ogo was added the same day lights came on.

 

[Azedenkae]

Do you find it odd that the tank is developing GHA and other algae with such low nutrient levels? Especially since the ogo was added the same day lights came on.

Or the reverse, GHA and other algae are taking up all the nutrients, hence nitrates is read low.

 

[Randy Holmes-Farley]

Or the reverse, GHA and other algae are taking up all the nutrients, hence nitrates is read low.

Right. That's the whole intent of growing macroalgae.

 

[Azedenkae]

Right. That's the whole intent of growing macroalgae.

Yes. I am just saying before the macroalgae managed to soak up all the nutrients, the GHA and other algae was able to compete for the nutrients and is probably the reason why op saw their growth.

 

[Rmckoy]

I always thought as long as the algae is in the water the nutrient levels will still be present .
it’s not until it’s harvested to see a lower value test result ?

 

[Randy Holmes-Farley]

I always thought as long as the algae is in the water the nutrient levels will still be present .
it’s not until it’s harvested to see a lower value test result ?

Undetectable with a kit doesn't ever mean zero. Algae and other organics can potentially drive down nutrients by taking them up.