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PO4 Nightmare


heifinator

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I have a tank that is about a year old and am having some serious nutrient issues that I can't track down. I thought some other opinions might be helpful!

 

Tank was setup last August and did really good up until around January at which point I started to notice algae growth (hair, and these little green flower polyp looking things that grow very close to the rock). The hair algae is limited but the little green polyps are everywhere.

 

I checked po4 and it read near zero on a hanna. I assumed the algae was taking it up but knew I had an issue. I checked my source RO/DI to ensure I wasn't importing anything. TDS is around 1.

 

I increased my skimming, and started running GFO at the recommended dosage in a reactor with a light tumble. I also did a large 80% water change matching salinity and temp.

 

After about two weeks I checked everything again and my algae problem has ~ doubled and my po4 now reads at 0.20 on a phosphorusULR hanna.

 

I've been fighting this cycle since January. I change GFO every 2 weeks, do a big water change, and test po4. It is always between 0.10 - 0.30. The algae isn't getting worse, but it isn't getting better and any stony coral frag I try to put in the system browns out immediately and then dies within a few weeks. My nano system using the same RODI water is doing fantastic and has zero issues keeping SPS and PO4 is undetectable in that system.

 

It is a 80 gallon tank and I am feeding a pinch of pellets daily with a supplement of a single mysis cube (rinsed) every other day. Bio load I would consider to be moderate, not high.

 

I have tried manual removal but the little flower looking algae is basically impossible to remove. Rock is reef saver from BRS, new with the tank, seeded with 3lb live rock.

 

Values.

 

Ph - don't know honestly.

Sg - 1.025

Temp - 78.5

Alk - 9

Calc - 440

Mag - 1350

Po4 - 0.10 - 0.30

Nitrate - 0

 

Lights- t5 with led (6 hours daily)

 

Thanks All!

 

 

 

 

 

 

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What is your sandbed like and what kind of maintenance do you do on the sandbed?

 

What things are different in this tank, compared to the other tank?

(even if it's simple)

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Appreciate the help.

 

The sandbed is tropiceden sand. It was new (rinsed) when I added it. It is about 1-1.5" deep and I siphon it with every water change.

 

The lighting is different, the other tank is pure LED while this is an ATI/LED hybrid. Bulbs are about 8 months old. The other tank doesn't run GFO while this one does. This tank has a skimmer, the nano tank doesn't.

 

Feeding is lighter on the problem tank and water changes more numerous.

 

I suspected my RODI water since I do more frequent and larger WC's on the problem tank. But it is testing at a TDS of 1 or 0. I will test PO4 on freshly mixed water, that is something I haven't done yet.

 

What is funny is I added cheato and a fuge light a few months ago to help and all the cheato started to die so I removed it before i released a bunch of po4. 

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I'll get a picture this afternoon.

 

The algae problem isn't catastrophic but there is a good amount. The bigger issue is the constant import of what seems to be loads of nutrients that are hurting or killing my corals.

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PE mysis cube every other day (rinsed with rodi) and then some pellets (small pinch) daily.

 

I am trying reallllly hard not to over feed.

 

 

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What is the filtration system?

 

You using any sponges? Carbon?

 

Do you use a turkey baster on the rocks?

 

I would feed frozen food lightly. Only 2 times a week.

 

Adding anything for corals like phytoplankton ot zooplankton?

 

What livestock is in this tank?

 

 

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80-100 total gallons of water

 

The tank has about 40lbs of BRS reef saver rock and a marine pure bio media slate (6" x 1") in the sump. The rocks are cleaned occasionally with a turkey baster but it doesn't get very much (2 MP40s no Nutrient export mode do a good job).

 

I add reef chili once weekly, very small amount.

 

Tank has

  • Kole Tang
  • Mystery Wrasse
  • Tri-Color Fairy Wrasse
  • 3 Dispar Anthias
  • Blue Spot Jawfish
  • Orange Spot Goby
  • Two Clowns
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17 hours ago, heifinator said:

Nitrate - 0

As far as a fuge goes, undetectable nitrate can be a limiting factor for algae growth.  You might want to supplement nitrate to get your fuge working.  However, low nitrate wouldn't stop GFO from working.

 

You're not carbon dosing are you?  You sometimes see 0 nitrate paired with phosphate when dosing vinegar (or another carbon source).

 

By increasing your nitrate, you might spark growth of the algae which is already established.  So care should be taken.

 

Maybe you need to solve the algae problem first, then get your fuge operational.  Maybe try fluconazole.  In the meantime, change out your GFO more frequently.  That can get a little expensive and it might affect alkalinity, so watch that.

 

The browning can come from phosphate as well as weak lighting.  Do you know what the PAR levels are in your tank?  What are your light settings?

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I don't know the par values but I doubt lighting isn't sufficent.

 

The tank is a 93 gallon cube with a Nano Box ATI hybrid (4x24" T5 + 6 nanobox arrays). Running the LEDS at around 60% at peak day and the t5s kick on for 5 hours.

 

I am not vinegar dosing no but that is an interesting effect. I will change out my GFO weekly.

 

I have tested my source water for PO4 via a phosphorusULR hanna checker and it comes out as zero.

 

My issue that made me post is that even with the GFO + Large water changes my PO4 levels don't seem to be dropping, in fact they are at times slowly rising. I have concerns that my bio filter is insufficent. I don't have a huge amount of rock (~35-40lbs) as the tank has an open aquascape. I am thinking about adding a few more marinepur plates to my sump to increase surface area.

 

I don't have a lot of fish or heavy feeding habits but the PO4 is coming from somewhere and really the system obviously doesn't have the bio filter needed to deal with it. I'm kinda at a loss though. I thought surely a bunch of GFO would help but over 3 months it really hasn't done anything but keep things stable at 0.10-0.30

 

 

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31 minutes ago, heifinator said:

My issue that made me post is that even with the GFO + Large water changes my PO4 levels don't seem to be dropping, in fact they are at times slowly rising. I have concerns that my bio filter is insufficent. I don't have a huge amount of rock (~35-40lbs) as the tank has an open aquascape. I am thinking about adding a few more marinepur plates to my sump to increase surface area.

 

I don't have a lot of fish or heavy feeding habits but the PO4 is coming from somewhere and really the system obviously doesn't have the bio filter needed to deal with it. I'm kinda at a loss though. I thought surely a bunch of GFO would help but over 3 months it really hasn't done anything but keep things stable at 0.10-0.30

Your tank's biofilter does not process phosphate, period.  Keep up with your water changes and switch out GFO regularly.  With high phosphate levels, GFO loses effectiveness quickly.

 

A refugium might be a more natural and economic method of controlling phosphate.  However, in order to get it to work, you  will likely need higer nitrate levels (as I discussed above).

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Fair enough

 

I'm just confused as I've burned an entire bucket of salt in the last 30 days doing water changes. Thats ~150 gallons on a system with no more than 100 gallons of total volume and yet PO4 is just as high.

 

I'll switch GFO every week instead of every two weeks and continue doing 50%+ water changes weekly. Thanks!

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Phosphate binds to calcium (your rock and sand).  So it's not just in the water column like nitrate.  Therefore, you might not see the immediate results that you would when trying to reduce nitrate.

 

Short of replacing your rock and sand, you will just have to continue to export more than you import.  Eventually, the phosphate will quit leaching from the calcium carbonate, and you'll start to make more progress.

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I think I might have an idea as to what happened.

 

When the tank was new and leaching PO4 I did lots of water changes to combat the PO4, however I exported nitrate as well. The nitrate in the tank is undetectable most of the time while the PO4 is quite high. I think I may be stepping into redfield ratio territory here.

 

My research has taught me that zero nitrate actually inhibits the uptake conversion of PO4 causing a "zero nitrate high phosphate" situation.

 

I have added more GFO to aggressively remove PO4 and am going to keep feeding (without water changes) to get my nitrates into the 5-10 range and see if that helps prevent this cycle of extremely rapid PO4 increase.

 

Good news is there are no sensitive corals in the system so I am not super concerned about shocking the inhabitants with rapid PO4 changes.

 

Will report back on if a small nitrate increase is helping keep the situation in control.

 

http://www.bareefers.org/forum/attachments/rr_table-png.1572/

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Just now, heifinator said:

I think I might have an idea as to what happened.

 

When the tank was new and leaching PO4 I did lots of water changes to combat the PO4, however I exported nitrate as well. The nitrate in the tank is undetectable most of the time while the PO4 is quite high. I think I may be stepping into redfield ratio territory here.

 

My research has taught me that zero nitrate actually inhibits the uptake conversion of PO4 causing a "zero nitrate high phosphate" situation.

 

I have added more GFO to aggressively remove PO4 and am going to keep feeding (without water changes) to get my nitrates into the 5-10 range and see if that helps prevent this cycle of extremely rapid PO4 increase.

 

Good news is there are no sensitive corals in the system so I am not super concerned about shocking the inhabitants with rapid PO4 changes.

 

Will report back on if a small nitrate increase is helping keep the situation in control.

 

http://www.bareefers.org/forum/attachments/rr_table-png.1572/

 

I like where you're going with this. 

Do please keep us updated on how this goes. 

  • Like 1
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Just now, Weetabix7 said:

 

I like where you're going with this. 

Do please keep us updated on how this goes. 

Will do, the more I read about the redfield ratio and the kind of issues you see with a bad ratio it really is exactly what symptom my tank was presenting.

 

Will update in a week or so!

  • Like 1
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It certainly sounds like the redfield ratio issue.

You could try phosphate Rx which is lanthanum chloride or similar - it rapidly reduces phosphate. Melev's Reef has many posts and videos about it. I have used it also.

At the levels you experienced, the phosphate binds to the rocks (as Seabass mentioned). Water changes help but it takes a while. 

To see if your rocks are leeching, you can pull one out and place it in a bucket of fresh saltwater (test PO4 before) with a small powerhead and test the water after 24 hours.

 

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Microbialhydra

Just my 2 cents but when ever I have higher phosphates I just dose some flourish nitrogen which is basically potassium nitrate. I also dose red sea nopox and have a fuge and oversized skimmer so nitrates always drop fast

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Yes, the Redfield ratio is what I've been talking about (without providing the name).

 

If your goal is to lower phosphate without growing more algae, just adding nitrate won't accomplish this.  What it will do is remove the limiting factor (low nitrate) and allow algae to start growing.  Also, given that you already have some established algae, I would hesitate to reduce your water change routine.

 

On 7/18/2017 at 10:21 AM, heifinator said:

I started to notice algae growth (hair, and these little green flower polyp looking things that grow very close to the rock). The hair algae is limited but the little green polyps are everywhere.

This algae will start to take off, especially with high phosphate levels.  I'm not sure that's what you want.  Do you have a picture of this algae?  I would be inclined to try and remove this prior to increasing nitrate levels.

 

Now, if your goal is to establish a working refugium, then adding nitrate would make sense.  The same goes for carbon dosing, a limiting factor can stall the uptake of the other two (whether it be carbon, nitrogen or phosphorus).  However, due to the ratio, carbon dosing is more effective at lowering nitrate than lowering phosphate.

 

As Kat mentioned, lanthanum chloride will bind phosphate.  But you'll want to remove the resulting bound phosphorus.  They make filters for this, or you can DIY one.  Some people are reluctant to add lanthanum chloride into their reef due to not knowing if there may a potential harm (although no short term harm seems apparent).

 

You might even consider using another media like Phosguard to reduce phosphate.

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Its likely not as doable as with a smaller tank, but you might want to consider hitting your rocks with peroxide before bumping nitrates up. It will remove a lot of the established algae and whatever nutrients in that biomass. Then if you restart your fuge and bump nitrates, there will be fewer things in the display to start explosive growth before the fuge can yank everything back down.

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56 minutes ago, bob115 said:

Its likely not as doable as with a smaller tank, but you might want to consider hitting your rocks with peroxide before bumping nitrates up. It will remove a lot of the established algae and whatever nutrients in that biomass. Then if you restart your fuge and bump nitrates, there will be fewer things in the display to start explosive growth before the fuge can yank everything back down.

However, peroxide can kill off beneficial non-bacterial life (like pods).  But yeah, dealing with the algae in the display before increasing nitrate (the apparent limiting factor) to restart your refugium, makes sense.

 

You could also try to find a herbivore that eats it.  However, that is often more of a challenge in a nano tank.

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Dunno if it's been said. It if you can't find a reason it's probably leaching from your rocks. What rock did you use? Where was it from? Not saying it's your issue but i have seen this happen to quite a few people.

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  • 2 weeks later...

So it has been almost 3 weeks since I made some adjustments to my system in an effort to correct this Po4 issue. 

 

Here is what I did

  • Ran full dose GFO exchanging every 5-7 days.
  • Added a cheato reactor (large).
  • Added 2mg/l nitrate to the system.
  • Changed feeding to light 2x daily instead of heavier 1x daily feedings.
  • Added a small amount of lanthanum chloride daily directly to the skimmer (dose to reduce tank Po4 0.05 ppm daily). Have stopped this now since Po4 levels have improved.

 

My Po4 is now steady at around 0.045 ppm. It does not appear to be going down anymore which leads me to believe that the rock is leaching faster than I can pull it out at this point.

 

At one point I did a 40% water change and after 24hrs measured Po4 and it was right back up to around 0.045 ppm. 

 

The algae in the tank is starting to die off a little bit and the reactor cheato is taking off. My nitrate was undetectable but now is holding at around 1-2 mg/l. I am holding this nitrate level via dosing.

 

Things are looking up but time will tell. Thanks all! :D

 

 

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