Phosphates to blame?

[N2theUnknown]

Hey everyone I have a 40-50 gallon cube it's pushing 9 months old plus a month and a half cycle. I have a fairly large 9 head reverse hammer an 8 head just normal we I guess a 7 head Duncan, 50 cent sized acan and a 9 head torch. Got them all this size about 2 months ago. No growth at all. Hammers and torch look great. Duncan has never really had great extension but over the past few days the Duncan has been closed up tight. I got a phosphate checker. Checked it and read .23. checked the instruction and retested. Again I get .23 is this my cause?

Alk= 9.0 dkh red sea
Cal= 410 res sea
Mag=1380 red sea

Temp held at 77 via ink bird
And salinity is 1.025

I currently don't have a major algae problem just kinda the normal "new" stage stuff some film algae and just very light covering of brown which is vaccumed out 2 times a month during a 20% water change.

Curently only run mechanical and carbon. I do have phosepure on hand. But what else could be causing my Duncan to suddly close.

 

[CuzzA]

I would try to bring it down to around .1, but more likely a lack of nutrition. Do you target feed your LPS? Some species get by without feeding, but by and large most LPS need food if you want them to grow. Remember closed aquariums are food deficient since we don't have the luxury of volume, like the ocean. So I will feed my LPS a few times per week. If my po4 is low I will fed foods with high phosphorus, like ReefRoids or small fish breeding pellets. If they are high I will feed foods with low phosphorus, which will likely be mysis, clams and fish.

 

[N2theUnknown]

I would try to bring it down to around .1, but more likely a lack of nutrition. Do you target feed your LPS? Some species get by without feeding, but by and large most LPS need food if you want them to grow. Remember closed aquariums are food deficient since we don't have the luxury of volume, like the ocean. So I will feed my LPS a few times per week. If my po4 is low I will fed foods with high phosphorus, like ReefRoids or small fish breeding pellets. If they are high I will feed foods with low phosphorus, which will likely be mysis, clams and fish.

Ok so how do I lower it slowly? The directions on the bottle say 1 tblsp per 20 gallons so I would need alittle over 2 table spoons. But how fast will that lower it should I just run the reactor a few hours a day?

And I do feed reef roids and mysis both once a week. They are also sitting under a g5 around 100-120 par which is what they where under in the previous owners tank.

 

[CuzzA]

Well you'll need a reactor to put the GFO in and tumble it. Just test everyday until you're in range. I run GFO continuously because I'd rather be able to feed corals often and keep my PO4 from climbing to high. I test po4 as much as alk, which is around two to three times a week.

 

[SliceGolfer]

You don’t mention nitrate, which could lead to a nutrition issue. When did you last calibrate the Inkbird? I found mine to be off by 3.5 degrees and now check it monthly.

 

[EmdeReef]

I think you need to look for issues elsewhere. If anything LPS Prefer higher nutrient water. And 0.23 is not too bad even for sps... What are your nitrates at?
Start by checking if anything is corroding in or near the tank. Any chance fish or inverts bothering your corals? I would also send an ICP test ASAP.

 

[N2theUnknown]

I'll start with nitrates.... I may or may not have kinda forgot about them for a minute haha and ink bird I've only had for a month so I'll check it's callabration and I'm going to pull all pumps and check them over good. It's just weird that it's just my Duncan. Gsp is even doing great which I forgot to mention above. I know it's hardier but still it's growing great lol

 

[N2theUnknown]

Nitrates are somewhere in the range of 10ppm. With api test kit

 

[N2theUnknown]

Also the only fish I have inhere is a lone zebra barred dartfosh

 

[Ling_Thing]

Your parameters looks great to me that n03 is p04 is fine it’s better to have it higher than lower corals will appreciate that. Have you done icp? How old is the tank? Prob flow or light issue...

 

[N2theUnknown]

Tank is around 8ish months don't think it's light they are all sitting around 110-125 par flow hasn't changed since corals have been placed

 

[kevin_e]

Aren't duncuns notoriously challenging to keep? I honestly wouldn't make wholesale changes for one coral if everything else is fine. You have no algae and the other coral seem fine? I'd just suggest brining the phosphate down a hair before it becomes an issue. Call it preventative care.

 

[N2theUnknown]

I'd never heard of Duncan's being hard but never looked into it either