View Full Version : High phosphate, and the tank is doing well....???

09/13/2017, 08:00 AM
The phosphate and nitrate level have been climbing up since April. No live stock addition and nothing changed in my husbandry practice. 12% water change every 2 weeks, I don't overfeed, and the tank is under-stocked.

Nitrate climbed from 0 to 9ppm, but it has stabilized at that level for couple of months.
Phosphate climbed from .02 to .27 and it doesn't seem to be stabilizing. (I tested 3 times with two different test kits)

The tank is doing great, and the corals are thriving and growing - SPS and LPS

Should I do something about phosphate? I am hesitant to use GFO, because the tank is doing well.


09/13/2017, 08:43 AM
If you aren't having algae issues and everything is doing great then no.. don't mess with it..
But I would probably say that you do overfeed if your phosphate is at that point.. ;)

09/13/2017, 10:04 AM
I have even higher nitrate and phosphate levels with great growth and minimal algae. Been considering carbon dosing but afraid to mess with stable system. Will change all my RODI filters first in case that's causing any issues.

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09/13/2017, 03:57 PM
I largely agree with leaving well enough alone. As long as the corals are fine, I wouldn't do anything drastic. I might look into the feeding levels, though, as the nutrient levels might become an issue at some point. We don't have much data on how dissolved nutrients affect our corals, though.

09/13/2017, 05:46 PM
Just tested.
Phosphate .78
Nitrate >50.

Looking closely I think I'm seeing the beginning of cyno outbreak on back wall and sand. Will increase water changes, syphon, and feed less.

Here's a recent photo of reef.


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09/13/2017, 08:06 PM
Well, I'm sorry to hear about the outbreak, but those sound like reasonable steps to me.

09/14/2017, 08:54 AM
Thanks guys.

09/14/2017, 12:34 PM
You're welcome. Good luck!