10-20 ppm Nitrate, No Measureable Phosphate

MarshallB

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Hi gang,

Necessary parameter dump:

125 gallon tank
44 gallon sump
Phosphate 0
Nitrate 10-20 ppm
Salinity 35ppm
DKH 10
Calc 420
Ph 8.3-8.4
RODI water
Instant Ocean salt

So i've ran into a issue in the last few months. My nitrates are consistently measuring between 10-20 ppm using Nyos. I get 0 phosphate reading on my hana checker. I run a refugium and I didn't really think the nitrate was an issue. Corals are doing fine and my fish are healthy. Now however, Im getting GHA starting to explode inside the display tank.

I started the tank in June of last year, it is now 12 months old. I started dry sand and dry rock and have run into about every issue you can run into. I had a outbreak of Cyano which lead into a outbreak of Dynos. Those two issues seem solved, at least i don't see any anymore. I measure nutrients once a week. Phosphate has always shown 0. Every once in awhile ill get a 0.01-2 reading. Nitrates have been steady 10-20 ppm for months.

During the Dyno outbreak I was measuring near 0 nitrate and 0 phosphate. The only change I made was removing my filter sock to increase nutrients in the tank and I started dosing microbacter 7. It cleared up in a month. I also added a goby to keep the sand turned over. All has been well up until a month ago.

I always had GHA growing in the fuge with my chaeto. I clean out my sump once or twice a month. I scraped it out, net out as much as I can then put on a filter sock for a few days to catch anything else. I run high flow and high turn over so nothing really settles in the sand. I figured if GHA was trying to grow in the tank the tangs were taking care of it.

All seemed well for a few months. However, GHA is starting to take over my rock work in my display. Very little GHA in the sump now. But tangs dont touch it. It is rooted into the rocks and is very difficult to pull off.

I've increased the light time in my sump to 14 hours a day, up from 8. I've reduced the amount I feed. I feed DIY frozen food with a mix of frozen fish, dried mysis and krill, fish eggs, aminos, with some algae flakes and pellets mixed in. I was feeding about two thumb sized pieces a day for 15 fish. A sheet of Nori every other day. I've cut the food down to half, but haven't noticed a drop in nitrate or a reduction in GHA. It's still growing strong.

I'm thinking maybe crank up the fuge light to 18 hours a day and maybe start filter socking it daily again. I stopped with filter socks because 200 micron felt socks needed to be changed out daily due to the amount of turn over I run. Nitrates also were not rising, but staying steady. I figured the chaeto is being limited to the low amount of phosphate in the system. However, there has to be some amount of excess phosphate in order for the GHA to thrive. I've also noticed a small spot of bubble algae. The thing is my Chaeto has never grown very fast. I'm using a Kessil h380 to light it. I've also got a powerhead to keep the flow strong in the fuge and I flip the cheato rack once every 2 days.

Any advice? I'm pretty sure its GHA and not bryopsis, but here is a few photos to go along.

20210609_124006.jpg 20210609_123934.jpg 20210609_123959.jpg

Fuge:

20210609_123916.jpg
 
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vetteguy53081

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Assure you’re not getting false results and adding a pouch of chemipure blue will lower and keep nitrate in check
 

Uncle99

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The question is is it really zero?

When my phosphate bottomed out, corals started not to look fluffy, colour was there, but not as vibrant.
Also, pest algae’s started to appear coincidentally.
Dosed phosphate up to 0.08-.1ppm (stable nitrate at 10)ppm and within two weeks, a clear noticeable difference in extension and colour.
I have been dosing about 1ml of product every 4 hours 8n a 180g for 3 months now and the phosphate doesn’t move.
Pest algae’s just seemed to disappear over the following 4 weeks.
 
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ScottB

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It is always a tough spot, when PO4 is unmeasurable and GHA is growing. When faced with that dilemma, I just go by what the corals are telling me. And do as much manual removal as possible. Using Vibrant has some risks, but have used it in a few situations. Not to "get rid" of GHA, but to soften it up and make it easier to remove.

Having been through dinos, I personally would be dosing PO4. I will take GHA any day over dinos.
 
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MarshallB

MarshallB

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It is always a tough spot, when PO4 is unmeasurable and GHA is growing. When faced with that dilemma, I just go by what the corals are telling me. And do as much manual removal as possible. Using Vibrant has some risks, but have used it in a few situations. Not to "get rid" of GHA, but to soften it up and make it easier to remove.

Having been through dinos, I personally would be dosing PO4. I will take GHA any day over dinos.

Absolutely. I'm not super worried about it at this point. However it is spreading slowly and I'd like to prevent a complete tank takeover.

I will also add some months ago I did start feeding more until I could get a phosphate reading, but then all sorts of things started growing in the display and the chaeto was getting covered in GHA so I backed off.

The phosphate was reading 0 long before the GHA was showing in the display. In fact since I've had the tank up i've rarely had a phosphate reading. I'm not sure if its just the food im feeding that may have very low phosphate or what it is. From what i've read most people are trying to do anything they can to reduce phosphate and not raise it.

Since the phosphate is low I'm not sure if its a good idea to reduce the food input. I can see my zoas are not fully extending as they were so Im assuming the GHA and chaeto may be just sucking up all the available phosphate.

Man as soon as you think things are going good nature just back hands you and says NOT TODAY!
 

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