I have a 90 gallon system with refugium, nearly non existent nitrate at .2 and for the past few days have been reading .36 phosphate and starting to grow diotom algea on my rock and specially on the bare bottom. Started running RowaPHOS about two weeks ago when it started elevating and gave it some time to see if it decreases, however, if anything it has gone up since. I Did a water change this past Sunday and yesterday started seeing a big spread of algea, like I said, specially diotom. I’m concerned that maybe my ro water could be the cause. Question? , if my TDS meter reads 0, could it be producing phosphate anyways, not sure how that works or if possible. Will appreciate anyone that has had the same issue or may have more experience to share his or her knowledge
High phosphate, low nitrates???
- Thread starter ToneReef
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hyprc
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You need nitrate to facilitate uptake of phosphate. Have you considered dosing NaNo3?
You could test your ro water and/or mixed saltwater for phosphate just like you do your aquarium to determine if it's coming from topoff/salt.
You could test your ro water and/or mixed saltwater for phosphate just like you do your aquarium to determine if it's coming from topoff/salt.
Little_Red_Ryan_Hood
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My first thought after reading your description was that you have dino not diatoms. Are you sure that your phosphate test is accurate. Having a refugium and running rowaphos should be effective at removing phosphate. Low nitrate and phosphate can result in a dino outbreak. Do you have another way to test phosphate or calibration fluid for your checker?
Scrubber_steve
2500 Club Member
I have the opposite problem, somewhat.
Run an algae scrubber; PO4 typically 0.02ppm. Even on a shortened scrubber photo-period, which results in a rise of NO3, PO4 stays the same. I just dose Potassium Phosphate occasionally.
Try dosing nitrate. @Subsea doses ammonia - ends up with the same result.
Run an algae scrubber; PO4 typically 0.02ppm. Even on a shortened scrubber photo-period, which results in a rise of NO3, PO4 stays the same. I just dose Potassium Phosphate occasionally.
Try dosing nitrate. @Subsea doses ammonia - ends up with the same result.
Little_Red_Ryan_Hood
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Do you have DI resin on your RO unit?
Little_Red_Ryan_Hood
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Maybe you should test the water coming out of the RO unit.
gotmesalty77
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i have the same issue i used gfo to bring down my po4 a bit and then took it offline. my nitrates are 10 to 20 ppm and everything is pretty happy around there. i think i shocked the system a bit by dropping the po4 much to fast. hard to find a balance for me it seems
Initially, when I started running Chaeto refugium thought about having to dose NO3 and PO4 because both of them where so low.. suddenly, high phosphate. I thought maybe I was reading the test wrong or just confusing the blues on the salifer test kit, so, by the time I received my Hanna,( today) it confirmed it, high phosphate and extremely low nitrates. But aren’t they suppose to pretty much work together, or maybe I’m wrong...
Yeah just started mixing a new batch to see if it’s my ro...
Little_Red_Ryan_Hood
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How healthy does you macro algae look? Is it dying and releasing nutrients back into the system?
gotmesalty77
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i found out i had ski high PO4 awhile back but i didnt see the algae outbreaks that was fore told by the elders. In fact i saw no negatives at all. it got a little too high so i lowered with gfo maybe a bit to fast. my fuge is rocking though. kessil h380 with chaeto and dragons breath
I’m on the same boat, but, my nitrates have neeeeeever gone up that high, however my corals don’t look bad, not that many, but have a few SPS and are pretty happy, it’s just that algea that concerns me, cause meaybe they’re looking good right now, but who know what I’ll happen in a week or two if I let it continue... that brown bare bottom is driving me crazy, lol
No, it actually looks good, nice and bright green. Coming to think about it, it all started when I cut about a 1/2 or a maybe a 1/4, I don’t remember, out, cause it was getting a bit huge. After that now that I think about, it’s when I started reading a bit higher PO4....
Scrubber_steve
2500 Club Member
I grow a species of Ulva in my scrubber, & have no hands on experience with chaeto in a fuge. I don't know if its because chaeto doesn't assimilate PO4 as highly as Ulva? Is any of your chaeto dying off & leeching po4?
What blue range on your Salifert did you get? I use too use Salifert, but I had to compare the test result against another vial filled with plain tank water to even tell the test solution had a faint bluish tint (approx 0.02ppm).
I started using Red Sea PO4 - very good low reading test - easy to read unlike salifert, but the test results was the same.
hyprc
Well-Known Member
Tough balance for a lot of us starting out. I had to go through a few methods of phosphate control before I found something that worked well consistently for me and my system. I'm sure I'll come across a system that challenges me to use another method in the future.
I have the same nitrite phosphate imbalance issue. I run large cheato refugium and heavy carbon dosing (vinegar) that brings nitrates to zero but doesn’t control my phosphates. Gfo never seemed to be able to keep up. I started nitrate dosing but it still isn’t enough.
If you’re not scared of potential for aluminum leaching, brightwell extraxphos worked way better for me than gfo to get my levels down quick. Very cost effective.
But I didn’t want to keep with that long term because I was afraid my toadstool leather might react poorly to aluminum. So I switched to lanthanum chloride dosing in the form of highly diluted (29:1) two little fishies phosban-L on a dosing pump that feeds into my skimmer neck. Has been brings my levels down slowly but I’m pretty sure all the rock in my system is still leaching phosphate since my system was at a high phosphate level for so long. If other methods of phosphate control aren’t working you might want to research lanthanum chloride. Just make sure you take it extremely slow if you choose this route and test often. With the potential for overdoes it’s not the most beginner friendly method, but probably one of the cheapest for a large system.
If you’re not scared of potential for aluminum leaching, brightwell extraxphos worked way better for me than gfo to get my levels down quick. Very cost effective.
But I didn’t want to keep with that long term because I was afraid my toadstool leather might react poorly to aluminum. So I switched to lanthanum chloride dosing in the form of highly diluted (29:1) two little fishies phosban-L on a dosing pump that feeds into my skimmer neck. Has been brings my levels down slowly but I’m pretty sure all the rock in my system is still leaching phosphate since my system was at a high phosphate level for so long. If other methods of phosphate control aren’t working you might want to research lanthanum chloride. Just make sure you take it extremely slow if you choose this route and test often. With the potential for overdoes it’s not the most beginner friendly method, but probably one of the cheapest for a large system.
gotmesalty77
Well-Known Member
I've been reefing since 2012 but this system has been challenging for me though. Ive been running high nutrients and everything has loved it. All about stability. I shouldn't of tried to come down.
That I can see, there’s no Chaeto dying At all, it’s actually growing pretty good and wouldnt know if it’s leeching phosphate. The shade of blue on salifer was between .1 and .25 so I got me a hanna checker, received it yesterday and it confirmed my worries, .36...
I’ll be looking in to that method. I thru in som chemi pure elite yesterday to see if anything happens.. I’ll give it some time and if nothing, will be looking at other options.. I definitely have to make a few adjustments because since a few weeks back I had such low nutrients was kind of feeding a bit extra, fish and coral.. and all of a sudden, the PO4 spike... since I wasn’t sure about the accuracy of the reading and since all corals looked good I continued going at it, until this week that the algea started spreading across my bare bottom and tested with Hanna. Tss
