Very low Nitrate / Elevated Phos - seeking opinions

guylaga

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Hello Everyone

Want to get thoughts on how to proceed onwards with the situation I am facing with my tank, with very low Nitrate but higher than optimal Phosphate. Below is as much background info as I can think, so apologies if this is long winded.

Tank information: Standard 125 gallon using Reefbreeder Photon V1s with standard 29 gallon sump, Reef Octopus 200 classical internal skimmer. About 100lbs of Macro Rocks and 80lbs + or - 10lbs of sand. Use Reef Crystals salt, BRS 6 stage RODI.

Current Livestock: 1 Yellow Tank (6 y/o) 1 Cherub Angel (6 y/o) 1 Marron Clown (6 y/o) 5 Azure Damsels (5 y/o) + Added 1 Starry Blenny and 1 Red Line Wrasse in December 2020 + Added 14 heads of Hammer Coral Jan 2021 and 1 each frags of M. Cap last week and M. Stellata about two weeks ago.

Currently about feed 1.5 cube to 2 cubes worth alternating LRS / Rods Food / PE Mysis / Enriched Brine Shrimp / Whole Clam + 1/8 strip of Nori daily.

Background Info: Originally set up late 2013, dry rock from Macro and dry Caribe sand, ran as a SPS ULNS until mid 2017 when I lost all my corals due to a heater being stuck on and so busy with work I didnt catch that tank had been running in the high 80s for several days. From mid 2017 to end of 2020 I let the tank run as FOWLR with only some GSP that survived the high temperature spike. No additional corals nor fish where added in those three years, as I got pretty down after losing most of very nice acros and montis, and I got lax on doing water changes as well.

During the FOWLR period I fed very lightly as I knew eventually I would get back into corals and did not want the rocks to start absorbing phosphate, I also turned my LEDs way down ( maybe 20% max) to avoid encouraging any algae growth due to my lack of regular maintenance.

Enter December 2020 when I got the itch again, I did weekly 20% water changes + started stirring the sand up small patches at a time. I also added a baseball sized clump of Chateo to the sump mid January which is now about softball sized.

All of my test kits had expired reagents so I ordered new ones, Once I was able to start testing again in mid January my Nitrates (Red Sea) where in the 5-10 ppm range while Phosphate was checked via Hanna was .44-47 ppm.

The addition of the Hammer Corals prompted me to increase lighting to 50% Blues / 30% Whites and subsequent Montipora additions I again increased lighting to 80% Blues / 60% Whites for 5 hours in the morning and gives me about 275-300 Par on the very tops of my rock work and 100ish on the sand bed. I also got a second hand Kessel Amazon Sun and have that running over the Cheato on an opposite schedule from the display lights.

With the increase in lighting I started to see very slight turf algae development, mostly on the rock work that has the highest amount of flow hitting it which does not get grazed on by the YT.

Starting February 9th I put my old BRS media reactor online with 1 cup high capacity GFO and 1 cup ROX Carbon. I started to track phosphate closely and got the following results

2/9 Phos .46ppm / Nitrate at 5ppm / dkh 10 (Hanna)
2/10 Phos .16 ppm
2/12 Phos .09 ppm
2/13 Phos .09 ppm
2/14 Phos .03 ppm
2/22 Phos .10 ppm / dkh 9.1 / Nitrate less that 5ppm - I noticed reduced flow through the reactor, so I shook up the GFO and Carbon but did not replace yet.
2/23 Phos .06 ppm / dkh 9.4
2/25 Phos .05 ppm / dkh 9.1 / Nitrate appears to be 0 ppm

I have not tested today, but will when I get home after work.

Now my future tank goals are to go SPS acro heavy again, I feel that Phosphate is coming in line but worried with the lack of Nitrates, especially since Reef Crystals mixes so high on Alkalinity and want to avoid burnt tips.

So in order to get my Nitrates up, but keep on the path to lower phosphates what should be the best course of action moving on?

Feed more food or increase live stock? (All fish are very plump but do plan to add a CBB and likely another wrasse down the road)
Dose Nitrate? (worried that I might see increase in algae in the display)
Decrease photo period for the chateo? (Is it sucking up all the Nitrate?)
Run the skimmer on a reduced schedule?

Do something else that I am not thinking of, or am I just over thinking all of it?

tl:dr - My nitrates are very low, phosphates on the high side, what to do?
 

laverda

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I would not consider. 05 high for phosphates. What are you aiming for? Personaly i would remove the GFO at this point before you phosphate gets too low. Yes your nitrates are low. I would reduce the light cycle on your cheeto to increase nitrates. If need be I believe people use stump killer to increase nitrates. Do a search in this forum.
 
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guylaga

guylaga

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Trying to shoot for less than .03 Phos and at least 5 on the Nitrates.

Like I said maybe I am just over thinking all of it?
 
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guylaga

guylaga

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Well tested Phosphate three times this evening, got .11, .12 , and .08.

Shook up the GFO canister, will run it overnight and test again in the morning.

Also will reduce the Chateo photo period from 12 hrs to 8 hours.
 
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guylaga

guylaga

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Phosphate up to .15ppm this morning. So I guess that the GFO reached capacity.

Going to change out my GFO but only add 1/2 cup instead of the full cup I used last time.

Nitrates still tested to be 0 or maybe 1ppm, will keep testing daily to track how reducing the light schedule on the Cheato helps.

Will also increase feeding a bit, until I get closer to 5ppm Nitrate.
 
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