My journey with high nitrates and low phosphates

MetallicInk

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im posting this more to share my journey, granted it may be more of a on going story and be added to in the future, basically ive had this tank set up for 5
+ years and have continuously dealt with this issue and this is more for information to help those who are dealing with this same issue and the frustration that comes with it.
redsea reefer 250 (older model) so 2022 i began my journey with this tank trying everything to try to keep nitrates in check, from microbacter to other additives, any sort of nitrate removal from stocking the tank full of rock to adding pourous nitrate plates and bio balls, as well as changing out the sump to something larger that i could fit a refugium, after all the defeats i took a hiatus but have recently returned with a renewed determination to resolve this
march 14 : nitrates-75ppm phospates-0.00
march 15: 20g water change nitrates-47.2 ppm phos-0.09
march 17: nitrates 66.7ppm phos-0.05
march 19: nitrates 63.ppm
march 20: nitrates 58.4ppm
march 21:nitrates 26ppm phos- 0.00 (after two 10 gallon water changes from the sump taking as much detritus as i could find)(the last of my redsea coral pro salt)
march 22: nitrates 49.2ppm phos-0.00 (began dosing phos and nopox)
march 23: nitrates 42.5ppm phos-0.01
march 24: nitrates 47.6ppm phos-0.00
march 25: nitrates 38.7 ppm phos-0.06
march 26: nitrates 67.1ppm phos-0.01(bacteria bloom appears) (i do not have a uv on system so decided to just hold out, luckily it wasnt too cloudy)
switch salts to tropic marine coral pro
march 27: (20 gallon water change with new salt pulling as much out of display as well as any empty snail shells as i could find as i used to leave them for blue and red legged hermet crabs that used to be in tank) nitrates-9.4ppm phos-0.02
march 28: nitrates-14.3ppm phos-0.02

we continue as needed, basically i'm not sure as to the direct reason i have gotten the nitrates low enough to manage as i had multiple factors at play. the main ones i contribute to the success were large water changes (which are not easy for me as i have to haul 5 gallon buckets from my basement up stairs to where the display is) or a form of carbon dosing while keeping phosphates high enough for the bacteria to work, or pulling water diliberately from detritus areas like the fuge, sump or under the rocks in display.
 
I had similar results in my old 125. For about 2 years I was actively dosing phosphates to get detectable levels with my Hanna ULR.
 
I have struggled with this issue for years and have spent so much of my limited budget fighting nitrates, my tank would fluctuate so much in terms of nutrients and now over the last few days it appears to be stabilizing , I'll continue to post my test results.
march 29: nitrate - 14.2 phos - 0.04


ps- I have a lot of respect for you randy, I see you posting on a lot of posts here on r2r and taking the time to share some of your experience and knowledge with a random nobody, thank you
 
march 30: nitrate - 13.5 phos - 0.02
march 31: nitrate - 13.6 phos- 0.03
i almost feel like i should have posted my alkalinity with these numbers since that will be the next parameter i need to get more stable. any tips will be appreciated i will now post my results from the current time period for reference as well as calc and mag

---------------------------nitrate--------phosphate-----alkalinity----calcium-----magnesium
march 15 2026:------47.2--------------0.09------------------------------360-------------1110
march 17 2026:------66.7--------------0.19--------------8.0------------375-------------1140
march 19 2026:------63.9--------------0.05--------------8.2------------370-------------1110
march 20 2026:------58.4----------------------------------------------------------------------------
march 21 2026:------26.0--------------0.00--------------9.1------------370-------------1110
march 22 2026:------49.2--------------0.00--------------9.3--------------------------------------
march 23 2026:------42.5--------------0.01--------------9.1------------380-------------1140
march 24 2026:------47.6--------------0.00--------------9.3--------------------------------------
march 25 2026:------38.7--------------0.06--------------9.2--------------------------------------
march 26 2026:------67.1--------------0.01--------------9.2--------------------------------------
march 27 2026:--------9.4--------------0.02--------------9.4------------360-------------1125
march 28 2026:-------14.3-------------0.02--------------8.7--------------------------------------
march 29 2026:-------14.2-------------0.04--------------8.6--------------------------------------
march 30 2026:-------13.5-------------0.02--------------8.7--------------------------------------
march 31 2026:-------13.6-------------0.03--------------8.4--------------------------------------
 
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