Am I stripping out too many nutrients? SPS are Pale, but PO4 and N are slightly Elevated

[sgrosenb]

Hi all,

Fairly experienced reefer here with a tank that's been up for about 5 years. It's a 165g with Radion G4 LED / T5 combo light combo. Radions are run at the SPS AB+ spectrum, T5 are on for 6hr / day. I have an SPS-dominated tank with a medium-large fish load and bare bottom.

My PO4 remains elevated at ~0.30, but many of my corals are very pale and a few of them are dying. I'm confused as to how my corals are pale if my nutrients are elevated (N is 10-20ppm). As you can see by the pics below, I also have a bunch of colonies that seem fine. I lost a Homewrecker, Sunday Driver, multiple nice RRC frags, and a few others over the past 6 months. I can't seem to figure out how to lower my PO4 but also color up my corals.

PO4 has been a battle for pretty much the entire life of the tank; getting it down to the ~0.03 level (measured with Hanna ULR Phosphate Checker) has been nearly impossible unless I run GFO heavily (but slowly). If I run GFO, it always irritates my SPS corals and inevitably a few die. My PO4 hovers around 0.30, +/- 0.10 on any given week.

I'm wondering how I can lower my PO4 without hurting my SPS. I really don't like to use GFO - even when it's just a dribble output from the GFO reactor, it still irritates my coral. I've seen @SBB Corals and others theorize that GFO strips out other important "things" that SPS need, and it would seem that's my experience as well. I have no scientific evidence of this, just many years of observation of my SPS corals.

I have three main forms of nutrient export:

• Bubble King Mini 180 Protein Skimmer - I've tried running it 24/7 and for only 12 hours per day. Right now I'm 12hr / day
• Red Sea ReefMat 1200 - this thing is awesome by the way
• RowaPhos in a Reactor - I've tried running a lot of this with heavy throughput, which is not good. I've tried running a little bit with very light throughput - it can lower PO4, but it definitely pales out / eventually kills some of my SPS. I am not currently running any PO4.

Most other parameters are pretty well in-line with Reef Moonshiners numbers (attached is my most recent ICP-MS test - I get these done every month or two). They are all very stable historically.

Some extra info:

• Nitrate is generally 10-20ppm
• Currently just running the protein skimmer 12hr / day and the ReefMat fleece roller full time - no GFO
• I feed American Reef HPD, Nori, PE Mysis (1 cube), Rod's Fish Food (1 cube), and a few small pinches of pellets each day. I have 4x tangs, 1x Foxface, 4x lyretail anthias, 3x blue chromis, and a few other smaller fish.
• I feed Benepets BeneReef food once or twice per week
• Alkalinity remains steady at ~7.5 dKH via a Kalkwasser reactor, supplemented with B-Ionic ESV 2-part.
• Mag, Calcium, Salinity, Temperature, and other trace elements remain steady and in-line on a consistent basis
• I do 20% WC every 1-2 weeks with Tropic Marin Pro-Reef salt

I'm about as far from a chemist as you can get, but one theory I had was that, with my fleece roller and protein skimmer, somehow I'm not letting the fish waste run through the whole ammonia/nitrite/nitrate cycle, thus I am somewhat "starving" my corals. It would surprise me if that was the case, but I can't reconcile how I have N of 10-20 and PO4 of ~0.30, but yet many of my corals are very pale.

As a side note, I have let my PO4 rise to higher levels of ~0.50, but many of my corals slow down or stop growing and some start to turn brown-ish. Most of my corals also lack much pink at all.

Many thanks for any thoughts and advice.

-Scott

Pale/Discolored Corals:

JF Sunday Driver:

Vivid Rainbow Delight

JF Jolt

RRC LV:

Better looking corals:

Tyree Red Drago / Cali Tort

Walt Disney

Goldenrod

Oregon Tort

 

[jda]

You are looking to be able to keep the corals that are starting to suffer? Seems that way, but I am not sure. Is this the goal?

My opinion is that your waste products are too high for some of your corals. If you have excess waste products, then there is little chance that you do not have enough building blocks in the tank. Not all acropora can handle po4 at .3, but some won't care at all - I think that you are seeing that.

IMO, you need to keep import the same and really increase export. I have never seen any need to feed any coral food, but I also feed my fish a lot. Fish waste is superior, IMO.

Do you have room to add another skimmer? It helps. At least run your current skimmer full-time. Larger fuge can help too once it gets going. Maybe put a deeper sandbed in there for some no3 reduction.

I have never had issues with GFO, but I have run small amounts changed daily. My experience is that the lowering po4 is not a problem, but doing it too fast can be. LC might be safer for corals, but it can be dangerous for fish unless you can catch most of the flocculant somehow - again, have to go slow.

I am not sure that some of what moonshiners suggests might not be an issue for your pinks. I have no trouble with pinks with a calcium reactor, water changes and fish food for traces.

I think that you would see some benefits to swapping the heavy lifting with your lights. Let the T5s run full cycle and move the Radions to less time. This is probably small, but nobody ever says that their T5s sucked at growing acropora. If the corals are the main thing, then let the better light pull the weight. If you like the programs, thunderstorms, etc. more, then don't change. Kinda like the excess building blocks, the light difference might not matter for all acros, but it does for some. Nuance is big time here and not all folks understand it. Don't believe the "they all do the same things" argument... maybe for easy corals or hobbyists that cannot tell a difference.

 

[Lavey29]

Have you done a recent ICP to check everything? Everything you mentioned seems pretty decent but doesn't rule out a bacteria infection either.

 

[joaocdestro]

I bet your corals are starved. You need to transform No3 + Po4 in some real food for your corals!

I would dose carbon, to transform no3 + po4 + carbon in bacterias, and this bakterioplankton will fed your corals.

 

[Pod_01]

Based on the ICP your PO4 is in the 0.16 range, not a bad value.

I agree with jda that fish poop is important and I suspect your roller removes most of it. I would take it off line for few months and see what happens. There is such a thing as too much of a good thing could be detrimental.

Also your PO4/NO3 does come from the frozen food, I had same issue. I switched to high quality pellets and it is mostly under control. I do have elevated PO4 in the 0.1 range but my NO3 in 1-2.

Also I use carbon dosing as mentioned to feed bacteria that hopefully feeds the corals. I use TM Bacto Ballance at 0.5ml per 50 gal. Something you could try, see if it brings the deeper colours.

Good luck

 

[Hans-Werner]

I fully agree with @Pod_01 . Fish poop is important and the roller may be taking out too much starving the corals.

 

[Spare time]

You can use a refugium or algae scrubber to lower nitrate and phosphate if that is an issue. I am not on board the train of corals can't use nitrate. If they are starving, consider using something like vitachem marine added to your fish food. The leftovers of it can be used by corals as food (amino acids and such). Maybe try that or a simple amino acid mixture (therefore having 0 phosphate in the additive).

 

[jda]

I am not sure how a tank with rising residual waste products can have starved corals... at least with building blocks. There are things building that are not being used or levels would be rising. Perhaps the corals is starved from not getting enough sugars from the zoox?

 

[sgrosenb]

You are looking to be able to keep the corals that are starting to suffer? Seems that way, but I am not sure. Is this the goal?

My opinion is that your waste products are too high for some of your corals. If you have excess waste products, then there is little chance that you do not have enough building blocks in the tank. Not all acropora can handle po4 at .3, but some won't care at all - I think that you are seeing that.

IMO, you need to keep import the same and really increase export. I have never seen any need to feed any coral food, but I also feed my fish a lot. Fish waste is superior, IMO.

Do you have room to add another skimmer? It helps. At least run your current skimmer full-time. Larger fuge can help too once it gets going. Maybe put a deeper sandbed in there for some no3 reduction.

I have never had issues with GFO, but I have run small amounts changed daily. My experience is that the lowering po4 is not a problem, but doing it too fast can be. LC might be safer for corals, but it can be dangerous for fish unless you can catch most of the flocculant somehow - again, have to go slow.

I am not sure that some of what moonshiners suggests might not be an issue for your pinks. I have no trouble with pinks with a calcium reactor, water changes and fish food for traces.

I think that you would see some benefits to swapping the heavy lifting with your lights. Let the T5s run full cycle and move the Radions to less time. This is probably small, but nobody ever says that their T5s sucked at growing acropora. If the corals are the main thing, then let the better light pull the weight. If you like the programs, thunderstorms, etc. more, then don't change. Kinda like the excess building blocks, the light difference might not matter for all acros, but it does for some. Nuance is big time here and not all folks understand it. Don't believe the "they all do the same things" argument... maybe for easy corals or hobbyists that cannot tell a difference.

Thank you all for the valuable input. @jda I would tend to agree with you - if the Roller Mat was pulling out too much fish poop, how are my residual PO4 and NO3 levels high? I would be more tempted to try some type of carbon dosing, and possibly LC (very carefully and heavily filtered) to see if those combined can bring down my nutrients without upsetting my corals.

I will report back once I try a few things. In the meantime, I appreciate all the input and thoughts. @Hans-Werner do you have any further thoughts on how my roller could be pulling out too much "food" when my nutrients continue to rise?

 

[TCK Corals]

The sunday driver and the Lv photographed have that telltale look of white bugs. Check at night with a flashlight about an hour after lights go out

 

[bobnicaragua]

JDA is spot on like usual. I don’t follow the logic that your corals are starving when you have high nutrients.

 

[jda]

I like to have lower turnover throughout the sump to keep fish waste in the tank for a while. Each consumer only uses about 25-33% and the rest gets moved on to the next consumer... so the next fish that eat the poop, hermit, crab, etc can also produce waste for the corals too. In all honesty, other than surface oils, not much is making it into the sump anyway.

I believe that you have a window with some things in fish waste, like polyphosphates, organically bound phosphate and ammonia. After that window, they become residual waste in orthophosphate and no3. While some corals can covert no3 back into ammoni[a,um] and use ortho, the are not going to if the available forms are available, IMO.

Since I have seen some corals suffer with elevated no3 and po4, I want mine fairly low. I know that many corals do not care, but I want more than that subset... any coral at any time. I have never seen a detriment of having low residual waste products levels as long as I feed my fish a lot... ever. Calcification is faster too. The ONLY downside is that coralline grows SOOOO fast.

Building blocks of organic tissue (nitrogen, phosphorous, sulfur, etc.) are different than energy (carbon). Most energy comes from the lights through the zoox. It always amazes me that people focus so much on organic tissue building blocks and then want the least amount of quality and quantity of light as possible.

 

[jda]

As said above, pests can always be a problem so look like 5 times with an open mind. Some corals are not bothered by pests at all and some can get hammered... so don't expect to see a uniform reaction.

 

[sgrosenb]

Thanks all. @TCK Corals I will definitely check it out after dark. When you say "telltale signs", what in the pictures I posted made you think it might be pests? Thanks for any further detail - it may help me with other things I see in the tank.

 

[Hans-Werner]

@Hans-Werner do you have any further thoughts on how my roller could be pulling out too much "food" when my nutrients continue to rise?

Not really, but there is older scientific research of the Institute Oceanographique de Monaco which shows that corals react differently to feeding than to dissolved nutrients if I recall this right.

Viewing this more generally they seem to prefer particulate phosphate over dissolved phosphate, maybe because of regulation of the transfer between coral host and zooxanthellae. My personal experience is that feeding of fish, kind of food and particulate phosphate seem to play quite important roles for corals. So it seems logical that pulling out all of the particulate coral nutrients is not good for them, even when nutrient concentrations are a bit elevated.

This could also be an underinvestigated nutrient source in coral reefs which may explain how coral reefs can thrive in low nutrient seawater. Feeding on organisms only may not be the whole truth since the nutrients aquired this way may not be sufficient.