Phosphorus levels completely unstable

[Sebae]

Hello,

I think I've asked this question before elsewhere months ago yet I am still at a loss. I have had SPS success in the past without issue. This time around has been different. I could not get my SPS to grow in the slightest and they would slowly fizzle out and die over a period of weeks. I dosed nitrate (stump remover) and phosphate (Brightwell NeoPhos) to get the levels up to a detectable amount. This did nothing. I tried low but detectable levels but also high levels (25 ppm nitrate, 0.5 ppm phosphate).

I added live rock in an attempt to do... something? as I always had started with live rock in the past. I did experience a boom in growth and coloration shortly after that lasted for a couple of weeks then fizzled out (I don't know how to explain this). Growth and coloration was amazing for approximately two weeks.

Through all of this, my phosphate levels will not remain elevated and drop quickly. For example, on 1/29 phosphate was 0.34 ppm, on 1/30 0.29 ppm, and on 2/1 0.12 ppm. I am not using GFO or carbon dosing and am feeding the fish heavily.

The general parameters have been consistent: Alk 9.5, Ca 420, Mg 1400 although I was originally running an alk closer to 11 and have since dropped it slowly.

If anyone has any advice, I would greatly appreciate it.

Sincerely

 

[anthonys51]

I am not a expert in chemistry but fir your phosphates to go from .29 to .12 in 2 days without Gfo I would say is a testing error Don’t think it’s possible. Also you say growth was excellent for 2 weeks then nothing. I don’t understand Unless your measuring them. I can’t see how you noticed growth in 2 weeks.


On a side note. I never like dosing nutrients What ever you dose you have the capability to over dose in a very short time period. Why not simple get more fish. Over time nutrients will build up.

 

[Sebae]

I have strong doubts it is testing error as if the level gets close to 0 I see a lot of polyp retraction and tissue necrosis.

The growth in 2 weeks was noticeable without measuring.

I have tried adding fish. When I say I was feeding heavy, I really mean that. 6 or so cubes of frozen + some dry feeds in a ~70 gallon system. Phos will not remain elevated.

 

[anthonys51]

In 48 hours for your phosphates to go down .17 you would need a monster refugium and your nitrates would have to be very high
Corals and macro algae simple doesn’t use phosphates that fast.

Also for a 10 cm coral to grow to 11 in 2 weeks is fast. If you can eye the difference from 10 cm to 11 cm without comparing it side by side to something you got a super power

 

[cmcoker]

Noticeable without measuring could mean he saw new branches, growth tips, etc.
I've notice growth in a birdsnest over a couple weeks because of the amount of new branches that started appearing...

OP, How are you measuring phosphate?

 

[anthonys51]

I just think the op is all over the place. Needs to slow down. Not sure of the right way to say it. Too much info left out to really give the op an informed response.

 

[cmcoker]

I just think the op is all over the place. Needs to slow down. Not sure of the right way to say it. Too much info left out to really give the op an informed response.

Understood. I would also like to know more about how and when he is testing.
I've been experiencing some low phosphates myself. Got a 000 on hannah ulr checker several times. Bought some phosphate, and I guess my tank just needed to be threatened with the bottle because the readings went up to 0.031 after I bought the additive. Haha

 

[Sebae]

I'm using a Hanna ULR checker for phosphorus and then using their formula to convert it to phosphate.

 

[anthonys51]

Understood. I would also like to know more about how and when he is testing.
I've been experiencing some low phosphates myself. Got a 000 on hannah ulr checker several times. Bought some phosphate, and I guess my tank just needed to be threatened with the bottle because the readings went up to 0.031 after I bought the additive. Haha

No disputing that phosphates can go up and down .17 in a day. Heck with Gfo I bet I can do it in an hour but naturally in 48 it couldn’t deplete that much in a Reef tank naturally

 

[cmcoker]

I'm using a Hanna ULR checker for phosphorus and then using their formula to convert it to phosphate.

Are you performing the test in the same way every time? What is your test procedure, exactly as described in instructions? checking for smudges on the test vial? Placing the vial in the checker oriented the same way when doing the blank and test?
Is you feeding routine the same daily? Amounts and time?
Is the test sometime before a big feeding, sometime after?

There can be a lot of variables in test procedure, combined with the margin of error that could be contributing to these numbers. So, it may be that some changes in the routine could provide more expected variances.

 

[Sebae]

Fill the vial with 10 ml of sample water. Wipe with a kimwipe. Rotate to remove bubbles on the sides. Place in the vial and zero. Remove and fill with reagent. Shake to mix, wipe, remove bubble, insert and let run for 3 min.

Feedings do vary in amount and time but I would say its consistently high. Testing time is also varied but it never goes up after a feeding. Only after manually dosing phosphorus.

For what its worth, I don't have this weird phosphorus issue in my display, only in the frag tank. In the display, phosphorus is consistent or increases over time.

 

[Randy Holmes-Farley Verified Community Expert]

I don't see anything particular unusual in the chemistry or the changes in phosphate over time (it can drop fast after artificially raising it), but I'm not sure why the corals are not doing well.