Nitrate and Phosphate too high? What am I missing

nathancross3129 · Oct 5, 2023

Still having issues with high Nitrates and Phosphates. Just tested…
04 OCT @ 940pm
Nitrate: 35.6ppm
Phos: 0.19ppm
PH: 8.18
ALK: 11.4 Hanna
Added 100mL of NOPoX into the 5gal MAG every time I top it off. Doses 2800mL daily for MG stability
**did a 75gal water change last Friday. 5 days ago.

Tank system. Total water volume 475 gals.
300 gal display (mixed reef) 125gal (frag grow out tank), 150 gal sump, skimmer, filter socks x2, refugium, gfo container, carbon container, uV 60 watt,
This system set up has been running 10 months.

Rocks came from original tank 8 months ago and live rock (LFS bought) for rock scape in 300 and a few rocks in sump

I have recently (1 month) dosing phytoplankton daily. 10 oz daily.

I am not looking to get to zero, I just want it down near 10ppm Nitrate, 0.02ppm Phosphate.

What am I missing?

tbrown · Oct 5, 2023

nathancross3129 said:
Still having issues with high Nitrates and Phosphates. Just tested…
04 OCT @ 940pm
Nitrate: 35.6ppm
Phos: 0.19ppm
PH: 8.18
ALK: 11.4 Hanna
Added 100mL of NOPoX into the 5gal MAG every time I top it off. Doses 2800mL daily for MG stability
**did a 75gal water change last Friday. 5 days ago.

Tank system. Total water volume 475 gals.
300 gal display (mixed reef) 125gal (frag grow out tank), 150 gal sump, skimmer, filter socks x2, refugium, gfo container, carbon container, uV 60 watt,
This system set up has been running 10 months.

Rocks came from original tank 8 months ago and live rock (LFS bought) for rock scape in 300 and a few rocks in sump

I have recently (1 month) dosing phytoplankton daily. 10 oz daily.

I am not looking to get to zero, I just want it down near 10ppm Nitrate, 0.02ppm Phosphate.

What am I missing?

Those levels are "high" but not excessive. Any corals? Loads of algae? Besides the numbers, what is the issue they're causing?

Just a heads-up, 0.02 is within the margin of error on most at home kits so if you got down to 0.02 phosphates you potentially are at 0 which can be bad as well.

nathancross3129 · Oct 5, 2023

tbrown said:
Those levels are "high" but not excessive. Any corals? Loads of algae? Besides the numbers, what is the issue they're causing?

Just a heads-up, 0.02 is within the margin of error on most at home kits so if you got down to 0.02 phosphates you potentially are at 0 which can be bad as well.

Understood. Yes I have coral in both tanks. No full colonies but more than just little
Frags if that make senses. No issues with algae, just have to clean the glass daily.

No real issues, mainly corals seem to not be coloring up, none brown or bleach, just colors changed. Example is a mini colony I had was yellow and blue then changes green to blue.

Lavey29 · Oct 5, 2023

Your numbers are fine if your tank is happy. Don't chase...

nathancross3129 · Oct 5, 2023

Lavey29 said:
Your numbers are fine if your tank is happy. Don't chase..

Thanks

jda · Oct 5, 2023

There are plenty of corals that won't mind those no3 and po4 levels at all. There are also plenty that will not be at their best and would like them lower. The issue with people who have thriving corals at high levels is that most do not understand that they are in the first group. If you are happy, then just work on maintaining instead of lowering, but if you want corals in the second group, then you will have to do more work.

Do you have sand? If they depth is 2-3 inches and you leave it alone, the 10 month mark is around the time that the anoxic zones start to establish and they turn no3 into N gas. po4 can be harder - for a tank that size, filter socks and Lanthanum Chloride might be the cheapest and easiest way to go.

nathancross3129 · Oct 5, 2023

jda said:
There are plenty of corals that won't mind those no3 and po4 levels at all. There are also plenty that will not be at their best and would like them lower. The issue with people who have thriving corals at high levels is that most do not understand that they are in the first group. If you are happy, then just work on maintaining instead of lowering, but if you want corals in the second group, then you will have to do more work.

Do you have sand? If they depth is 2-3 inches and you leave it alone, the 10 month mark is around the time that the anoxic zones start to establish and they turn no3 into N gas. po4 can be harder - for a tank that size, filter socks and Lanthanum Chloride might be the cheapest and easiest way to go.

Thanks. I am trying to find a balance and to have coral colors pop more. I have sand/crushed coral substrate. Less than 2 inches in some spots. I have a sand shifting golbe that is kind of an butt.

I am using filter socks as well.

1ocean · Oct 31, 2023

This happend to me until I tested a fresh batch of water. Found out the RODI system was bad and needed to replace all the cartridges and once I did that. PO4 test was zero on the next batch of fresh water...

Randy Holmes-Farley · Nov 1, 2023

1ocean said:
This happend to me until I tested a fresh batch of water. Found out the RODI system was bad and needed to replace all the cartridges and once I did that. PO4 test was zero on the next batch of fresh water...

I don't know how much phosphate you detected, but I'll just add the comment that a little phosphate in top off water is not a significant concern:

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.

reefs.com

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the “crappy” RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let’s assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.

1ocean · Nov 1, 2023

Thanks Randy for taking time out to give me some advice and reading. Where I am in Arizona sometimes you can smell the chlorine and sometimes it has a rotten smell as my neighbors say. It is not so bad when that happens at my place as we have full water system. But the rodi for tank was coming from outside hose supply line. Anyway, when I did test the water BEFORE I changed all the cartridges in the rodi for the tank, Hanna check flashed 90 in the mixed salt. After I changed them all it was zero...So I guess either it was a bad supply of water from the city, a bad batch of water or the fact that the rodi system needed changing. Either way I will always test it before I make or add water to the 300 now. Lesson learned.