Phos-Feed - dosing in ULNS 3yo SPS only tank.

[MarcosB]

Hi!

I have 250gal reef full of SPS corals. I am dosing 7L of kalkwasser per day and also 350ml of each balling fluid per day.
If I calculate it properly daily KH drop without dosing is 1.8 dKH, so demand is high.

I am having problems with some sps species not growing and colors are very pale. I do not have problems increasing NO3, but my phosphates always show 0 or very very low. Max 10 ppb (Hanna ULR). Tank is 3 years old and all that time with very low phosphates. ICP tests also confirm that my phosphates are 0.01 or 0.02 , maximum 0.04 for last few months.
After 10 days of using Phos-Feed I still do not see ANY change in phosphate when testing. Im dosing 1 small measuring spoon per 50 US Gal per day.
I already see some minor color change on some corals and better polyp extension, I do see new growth tips on corals that stopped growing and I am very happy about that.

But my Hanna shows Phosphate - 0 still ;-). ( Checker is 2 months old as I supposed that maybe it is faulty, but it is not)

Should I wait with increasing dosage for those 4 weeks ?

Thank You for help.

 

[TangerineSpeedo]

I am getting my Phos feed on Thursday, so I haven’t tried it out yet. If I understand correctly you really should not be able to test for this because it is an organic phosphate. Give @Lou Ekus a shout, he probably can answer your ?

 

[Hans-Werner]

Phos-Feed is particulate phosphate that will not dissolve in the free water. It needs bacterial digestion to release its phosphate.

Since especially SPS but also LPS, gorgonians and soft corals are very efficient filter feeders, they will filter the particulate phosphate out of the water and bacteria in the slime and in den stomach of the corals will release the phosphate. This is why you see an effect in the corals but you can't find phosphate with testing in the water.

We made an interesting trial: Half an hour after dosing of Phos-Feed we took a sample of unfiltered aquarium water and a second sample filtered through a 0.2 µm syringe filter. The test "digested" the particulate phosphate because it uses very acidic reagents to lower pH of the sample. In the first unfiltered sample we found an increase in the phosphate concentration while in the second filtered sample we found no phosphate increase. The difference was the "particulate inorganic phosphate (PIP)" we suspended in the water by dosing Phos-Feed.

For corals the PIP is available through filtration and subsequent digestion.

 

[Pod_01]

It needs bacterial digestion to release its phosphate.

Just a quick question or two? What happens to any particulates that don’t get consumed by the bacteria?

Do they float harmless in the water or do they get skimmed out filtered out?

Also if the bacteria is not consumed by the coral because it is the biofilm on the rock or sand or glass. Could you end up with PO4 build up in the rock and sand that could lead to other issues down the line?

Just curious…

 

[Hans-Werner]

To the phosphate particulates that don't get filtered by corals the same as to particulate food happens. The particules settle or adhere to glasses and decoration where fish, polychaets and other detritus feeders may feed on them and in this way help to fulfil their phosphate needs, i. e. in fish for skeletal growth.

Another part of the particules may get skimmed out or filtered out.

If algae or cyanobacteria are in the tank also these may benefit from the phosphate particules, in our tanks to a lesser degree since I try to keep the algae nitrogen limited with very low nitrate concentrations.

Since the phosphate particules are insoluble in saltwater with its high pH, bacterial activity or low pH is necessary to release the phosphate from the particules. I am not sure if the phosphate gets into rocks and sand to a significant degree. However, it can enrich biofilms with phosphate and in this way have an effect that is a bit similar.

 

[Pod_01]

To the phosphate particulates that don't get filtered by corals the same as to particulate food happens. The particules settle or adhere to glasses and decoration where fish, polychaets and other detritus feeders may feed on them and in this way help to fulfil their phosphate needs, i. e. in fish for skeletal growth.

Another part of the particules may get skimmed out or filtered out.

If algae or cyanobacteria are in the tank also these may benefit from the phosphate particules, in our tanks to a lesser degree since I try to keep the algae nitrogen limited with very low nitrate concentrations.

Since the phosphate particules are insoluble in saltwater with its high pH, bacterial activity or low pH is necessary to release the phosphate from the particules. I am not sure if the phosphate gets into rocks and sand to a significant degree. However, it can enrich biofilms with phosphate and in this way have an effect that is a bit similar.

Thank you for the reply. Now for some more questions.
Do I use this when PO4 is below particular level? Let’s say below 0.05?

When used do I need to reduce other coral foods like Zootonic, Phyton, Amino-Organic etc…? Or reduce trace elements ? Or no adjustments required?

 

[Hans-Werner]

Do I use this when PO4 is below particular level? Let’s say below 0.05?

When used do I need to reduce other coral foods like Zootonic, Phyton, Amino-Organic etc…? Or reduce trace elements ? Or no adjustments required?

I recommend to use it if the phosphate concentrations are below 0.1 ppm. I expect you see a difference after a week.

Up to 0.15 ppm phosphate I suggest to just give it a try and see if it improves color and growth of your corals. I expect this will turn out positive in more tanks than you might initially think.

In my eyes it is not necessary to use other coral foods when using Phos-Feed. However you can continue using other feeds if your corals look better in your eyes or you feel better.

In our tanks I try to get good colors, polyp extension and regular growth of corals. I want to achieve this goal with the smallest possible effort. For this I try to get the corals nitrogen limited and well supplied with phosphate. Since we have some fish in the tanks, the corals don't get bleached or particularily lightly colored but not dark either.

A good phosphate additive was one of the last jigsaw pieces to control tank nutrients according to my and your requirements. The goals may differ and also the number of fish and the nitrogen load in tanks may differ. I try to give you good tools, you need a plan what you want to build.

 

[MarcosB]

I do see some minor difference on coral colors, but still my phosphate reads - 0 PPB Already 10 days dosing regular dose. Should I increase ?

 

[Pod_01]

I do see some minor difference on coral colors, but still my phosphate reads - 0 PPB Already 10 days dosing regular dose. Should I increase ?

Knowing Hans-Werner preference I suspect the idea is for the P/PO4 to be available but not to pollute the water so most of it will be consumed by bacteria/ biofilm and the rest will be inert.

Since the phosphate particules are insoluble in saltwater with its high pH, bacterial activity or low pH is necessary to release the phosphate from the particules.

As long as your PO4 is below the stated level I would just keep dosing the recommended dose.

Up to 0.15 ppm phosphate I suggest to just give it a try and see if it improves color and growth of your corals.

Hopefully the corals keep growing.

 

[Hans-Werner]

Hopefully the corals keep growing.

I see no problem up to at least 0.5 ppm phosphate.

I suggest the following experiment: Don't check phosphate for some time. Try to see changes in your corals, hopefully improvements in colors and growth. Try to tell what your phosphate concentration has done. Did it rise or drop? Then check what you find. Did it do what you expected after your observations of the corals?

Repeat this experiment several times. Do you get better in predicting changes in phosphate concentrations?

 

[bandando]

To the phosphate particulates that don't get filtered by corals the same as to particulate food happens. The particules settle or adhere to glasses and decoration where fish, polychaets and other detritus feeders may feed on them and in this way help to fulfil their phosphate needs, i. e. in fish for skeletal growth.

Another part of the particules may get skimmed out or filtered out.

If algae or cyanobacteria are in the tank also these may benefit from the phosphate particules, in our tanks to a lesser degree since I try to keep the algae nitrogen limited with very low nitrate concentrations.

Since the phosphate particules are insoluble in saltwater with its high pH, bacterial activity or low pH is necessary to release the phosphate from the particules. I am not sure if the phosphate gets into rocks and sand to a significant degree. However, it can enrich biofilms with phosphate and in this way have an effect that is a bit similar.

Hello Hans-Werner,
my experience is different.

I had problems with low phosphate and I dosed Phos Feed.

For a long time PO4 was always to zero and after, in a few days, it rised to 0.4-0.5 mg/l.

I’ve already opened a new thread about this.

I had to dosed Elimini Phos Rapid for bring the value to 1.4-1.5 but the phosphate continue to rise when I stop it.

 

[Hans-Werner]

Hello Hans-Werner,
my experience is different.

I had problems with low phosphate and I dosed Phos Feed.

For a long time PO4 was always to zero and after, in a few days, it rised to 0.4-0.5 mg/l.

I’ve already opened a new thread about this.

I had to dosed Elimini Phos Rapid for bring the value to 1.4-1.5 but the phosphate continue to rise when I stop it.

Why do you want to dose Elimi-Phos Rapid? Do you see adverse effects of the higher phosphate concentrations oder do you want to do it just for the numbers?

 

[bandando]

Yes, with phosphate to 0,5 I didn’t have algae but the corals didn’t stay well, at my eyes obviously.

 

[MarcosB]

Ok My phosphates finally started to show up on my test. For last 2-3 weeks I have stable PO4 levels at 0.08 - 0.12 and I am pretty happy about it. Some acros really like higher PO4 levels.

My question is should I keep dosing Phos Feed ? I did not increase initial dosage - so for me it was enough.

 

[Hans-Werner]

Ok My phosphates finally started to show up on my test. For last 2-3 weeks I have stable PO4 levels at 0.08 - 0.12 and I am pretty happy about it. Some acros really like higher PO4 levels.

My question is should I keep dosing Phos Feed ? I did not increase initial dosage - so for me it was enough.

I recommend to adjust the dosing to the demand. I expect the phosphate concentration to be quite stable now since the particulate phosphates themselfes act as a kind of phosphate buffer and the rocks and sand are also loaded to buffer the concentration you find now. This means you can stop or pause dosing if phosphate concentration doesn't drop. Just dose if you want to increase the phosphate concentration.

 

[MarcosB]

Thank You for fast response. I think many people will find it very helpful.