Oddly high nutrients

[Heifinator]

Hey all. Have a 90 gallon cube sps tank (currently mostly frags) and am having some weird nutrient issues.

The tank has been up for about a year and I have fought with nutrients pretty much the entire time.

Currently the parameters are

SG: 1.025
Temp: 78-79
Calc: 420
Mag: 1300
Alk: 8.7dkh
Po4: 0.095ppm (hanna ULR Phosphorus)
No3: 10ppm (Salifert)


Lighting is provided via 4 ATI t5 and 6 nanobox led arrays at around 60%. Flow is provided by 2 MP40s.

Nuisance algae is under control but its almost everywhere. Short hair alage and cladophoropsis have the biggest presence.

Filtration is provided by filter socks, a bag of carbon, vertex 180i, GFO reactor, Cheato reactor, and No3Po4-X (9ml daily carbon dose).

There are ~9 fish in the system.

Water changes are done with Red Sea salt at ~35% weekly. Coral health is improved after a water change but after about a week it begins to decline again, hence the aggressive water changes.

I am looking for advice because I am at a loss with this system. Between extreme filtration and light feeding I expected some improvement but I have made no changes in the last 8-12 weeks and have seen no reduction in Po4 or No3. It is completely stable around 0.1ppm Po4 and 10pmm nitrate.

Any help would be appreciated, thanks!

[mcgyvr]

Thats not "high" by any means really nor odd..

But simply put your output is less than or equal to your input at this time ..

You GFO clearly is likely exhausted too and you are under the recommended dose of the nopox..
What is "light feeding" to you?
And how big are these 9 fish?

I personally would up the nopox dose..

How much rock do you have in the tank?
Sand bottom? how thick? what size grain?

[Heifinator]

Thats not "high" by any means really nor odd..

But simply put your output is less than or equal to your input at this time ..

You GFO clearly is likely exhausted too and you are under the recommended dose of the nopox..
What is "light feeding" to you?
And how big are these 9 fish?

I personally would up the nopox dose..

How much rock do you have in the tank?
Sand bottom? how thick? what size grain?

It is high enough to generate a substantial amount of nuisance algae and browning SPS corals.

GFO is changed bi-weekly. The system has around 80-85 gallons of water.
its 3/ml per 25 gallons so I went with 9ml. I can up it but Red Sea explicitly says not to go above the recommended dose. I could go to 10ml and still be at or under that.

3x Anthias, Kole tang, bluespot jawfish, 2 clowns, mystery wrasse, Single chromis.

Sand bottom is around 1/2" thick (siphoned with every water change) reef flakes (around 2-3mm size). Around 40-50lbs of reef saver dry rock seeded with 5lbs live rock during cycle / startup.

Thanks!

[Heifinator]

Also, light feeding is 1 cube mysis rinsed 3 days weekly and NLS pellets daily (single pinch ~30 - 40 pellets).

[mcgyvr]

You are pretty low on the amount of rock.. Not even close to 1lb per gallon.. and don't have much sand so you are likely "low" on the surface area compared to a tank with 100lbs of rock and a 2-3" sand bed..

Thats not really "light feeding" either IMO..

But statement still stands.. output is less than or equal to input..

[Heifinator]

You are pretty low on the amount of rock.. Not even close to 1lb per gallon.. and don't have much sand so you are likely "low" on the surface area compared to a tank with 100lbs of rock and a 2-3" sand bed..

Thats not really "light feeding" either IMO..

But statement still stands.. output is less than or equal to input..

I should disclose that I also have 4 1" marinepure ceramic bio media plates in my sump with flow moving through them.

I understand well the idea of import / export. I guess I wasn't clear in the OP. I'm looking on advice on potential solutions to this, not identifying the problem.

I already run what I feel is significant export (oversized skimmer, GFO, socks, cheato reactor, carbon dosing, large frequent water changes) and yet still have stable or slowly rising nutrient levels.

Thanks!

[mcgyvr]

Its just not enough export..

I'd stop the cube feeding personally.. or cut it way back...1cube a week if that..

And I'd also remove the filter socks.. I'd rather have food continually circulating to be used up vs just being stuck in a sock not doing anything..

I'd also probably remove the GFO and rely on the carbon dosing..

People put too much faith in skimmers/chaeto reactors.. They just aren't the magic people make them out to be..
I'd take 1lb of rock per gallon or more over a skimmer and reactor combo anyday..

[Heifinator]

Its just not enough export..

I'd stop the cube feeding personally.. or cut it way back...1cube a week if that..

And I'd also remove the filter socks.. I'd rather have food continually circulating to be used up vs just being stuck in a sock not doing anything..

I'd also probably remove the GFO and rely on the carbon dosing..

People put too much faith in skimmers/chaeto reactors.. They just aren't the magic people make them out to be..
I'd take 1lb of rock per gallon or more over a skimmer and reactor combo anyday..

I was always under the impression that rinsed frozen was WAY lower in Po4 binders than flake or pellet. Is that an incorrect assumption?

Had the skimmer since day 1 but recently added the reactor, its actually the one thing that has made a reasonable improvement. The Po4 has been steady since adding that instead of slowly increasing, go figure.

What is the logic behind removing an export method such as GFO if I have higher than acceptable Po4? Thanks for all the help!

[Dan_P]

Some thoughts on your situation.

The large water change schedule seems excessive. Not sure what you mean by coral health decline but something might be going on here. You shouldn't need to change the water that much to keep coral looking healthy.

No changes in nitrate or phosphate level could mean export = import. If levels are not changing, one could say that your system is at steady state. To reduce nitrate and phosphate level, the system needs to assimilate more nutrients. GFO can aggressively remove phosphate. I would check your GFO reactor. Maybe the flow is too low or it's clogged. Also, does your nitrate levels drop with each water change? If not, you might have an issue with the new salt water or RO/DI. Does the nitrate level decline after a water change and pop up immediately?

Aggressive vacuuming of substrate could inhibit denitrification. With only a 1/2 inch of sand that is vacuumed weekly, you might be harming your biofilter

What is in the aquarium to eat algae? Nutrient control is important for algae control but are you also using predation to fight the issue?

[bertoni]

Given the amount of food going into the system, I agree that the nutrient level is reasonable. Rinsing frozen food will remove any surface layer of phosphate, which will reduce the amount of phosphate dumped into the water immediately, but it's not going to do much else unless you're throwing away a good portion of the food. In order to be nutritious, food needs a lot of phosphate in it. Rinsing whole food items like mysid or brine shrimp makes sense, but it's not going to make the food phosphate-free. Personally, I never bothered, but my feeding levels were much lower.

I don't know how much live rock the MarinePure plates can replaced, but if the system were live rock only, I might add 75 lbs or more of live rock. Were the plates added recently? Maybe they haven't ramped up yet.

The GFO might be able to cut back on the algal growth, but you will need to ramp up the quantity. Once the water out of the reactor matches the level in the tank, the media is shot. That might take only a few hours, unfortunately. If GFO seems to expensive, then lanthanum chloride is a cheaper solution for high phosphate levels. At this point, I'd expect that the live rock and sand are leaching phosphate as the GFO removes it, so reducing the level might take a lot of media.

Given the small depth of sand, I don't think it'l do much denitrification. What does the sand look like if you don't vacuum for a few days or so?

I agree that some herbivorous snails might help, too.

[bif24701]

What is your skimmer? Does it seem to skim well?

How effective is the chaeto reactor? How long does it take to double the amount of chaeto after a harvest? In two weeks my fuge goes from this:
https://uploads.tapatalk-cdn.com/20170928/7722f1693057ce1572b2acd70d2af384.jpg
To this:
https://uploads.tapatalk-cdn.com/20170928/15c50b4b9bc5920fc28ff222f8d9420e.jpg
And I harvest this:
https://uploads.tapatalk-cdn.com/20170928/7288a7cc0ec09fcf7d2cadfe6402a9a7.png
About every two weeks.

Your reactor should have explosive chaeto growth with those nutrients. That is if you have enough flow and light.

Reduce input, no pellets, clean high quality frozen. Clean/change filtration at least every 2-3 days! I'm talking about your skimmer, filter socks, chaeto, and any other physical filtration. Longer than three days and any particles trapped will break down into PO4 and NO3. Once it's PO4 and NO3 it's much harder to remove.

Removing PO4 in order of effectiveness: GFO, WC, chaeto, carbon dosing.

NO3 removal: WC, carbon dosing, natural denitrification in rock/sand/MarinePure blocks etc......

I can help you though. Over dosing organic carbon. Dose carbon like nuts bro! Slowly increase over several days but not so much you can not actually see through the water but you will certainly see snot, cloudy water, everything covered in white film, that sort of thing, if you do it right. Monitor your NO3 and when it starts to actually drop some then you can back off a little until it's low (<1ppm). This can be risky if you do not have good gas exchange, but if you have good flow and a skimmer then you will be fine.


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[tkeracer619]

The phosphate could be leaching from the rock. In time it should slow down. I wouldn't worry so much at this point unless something is being harmed and keep doing what you're doing. It doesn't seem that abnormal to me all things considered.