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Now no nitrates?!

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So a few months ago I finally tossed the API kits that were saying my nitrates and phosphates were zero (Hanna had NO3 at 100+, and PO4 at 0.90). I almost tried NOPOX for the first time, but went with your recommendations to stick to the water changes and add some GFO.  I also added a "mini refugium", and it all seems to be working too well now.  I still need to bring my PO4 down a bit (.15 yesterday), but my nitrates have been 0.0 for a few weeks now.  I've had the skimmer off for a week, increased the fish feedings, and started dosing NeoNitro to try and get them up to around 10-15.  Nothing seems to work though.  I also tried dosing some AB+, but it started to crank up the green hair algae growth, so I stopped.  

I'm not chasing numbers, as half my softies don't seem to be doing well and are normally pretty hardy (GSP, Xenia, kalaidascope polyps, etc).  Anything else I could be missing?  I haven't done a water change in 2 weeks, as I'm hoping that may bring the NO3 up a bit.  However, I noticed it dropped my salinity down (1.022, where it's normally 1.026). Could that be part of the problem?  Other parameters include:

Alk: 8.6, Calc: 498, Mag: 1194, Ph: 8.1, temp: 79


Thanks for the advice!


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from my personal experience with Dino's... Stop the rocket fuel (any form of Amino's, eg: AB+) until after you're above zero on both NO3 and PO4.

If you've got to dose NeoNitro every day (matched with testing every day to monitor it), then do it.   Lots of people does NeoNitro.

Of course, be paranoid about your readings.   Borrow a friends test kit, try new reagents, ...    don't go off the deep end at once.

But I bottomed out my NO3 and PO4's a number of times in 2021, and it was a very bad and humbling experience.

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A couple of things to know.  If you using flake food, it has a lot of phos in it.  As does store bought frozen fish (most).  While food will certainly add nitrates, nitrate is primarily the by product of ammonia which comes from the gills of fish. I know, I know everyone thinks that ammonia comes from fish poop and pee but it doesn't. Feel free to google it.  Saltwater fish RARELY "pee", their environment is saltier than they are and they have processes to retain water, they don't actively expel it. 

Phosphorous is typically the limiting factor in algae growth.  If you have lots of algae growth, then your phos is high.  Yeah, the need nitrogen, but they need phos more.  This is a dramatic oversimplification but it serves the purpose of letting you get a feel for tank conditions based on observations. 

Having high phos with zero nitrates would be a VERY weird occurrence. If a hanna said your No3 was 100 then I would be willing to bet that you do not have zero nitrates.  Loosing nitrate through biological activity > conversion of nitrogen gas > and outgassing is  a slow process. 

I would suggest double checking your test results or take it to a LFS.  At the very least, give us some info on your tank. Gallons, fish, etc etc.  Not to dig on you, but if you let your salinity drop to 1.022, you need to apply a little more effort a be more cautious.  The only thing that will lower your salinity is improper mixing of fresh sea water (or a top off error).  Swinging your salinity does VERY BAD THINGS to the concentrations of important ions.  cal, alk, mag, well, everything actually (except waste numbers). 

Hope this is helpful. 


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