Leeching Phosphate

[ZCape35]

Hi everyone.
I took over a 6 year old tank and it had been neglected. The Nitrates were over 160 and the Phos was at 4. Yes 4.
I have slowly brought them down. Due to cleaning and water changes I have the nitrates at 25.
The Phos has been brought from 4 to now .1
The catch is that it must be leeching from the old rock. (New sand and clean sump). It currently leeches .1 Phos every day. I lowered it using Phosphat-e. Should I just keep dosing this until the leeching stops? I need to dose 10 ML to lower the Phos .1.
I do have a GFO reactor but feel like it’ll get used up rapidly at that rate.
I just started NoPox the other day but I believe that’s mainly for the Nitrate.
Thanks!
Fwiw I’ve only been feeding frozen food and Nori. No reefroids or anything like that.

 

[Randy Holmes-Farley Verified Community Expert]

All foods contain phosphate, and frozen foods can contain a lot. Two Prime reef Cubes in 100 gallons of seawater would add the 0.1 ppm you mention.

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.

reefs.com

But the rock is also expected to be holding a lot as you try to bring levels down. It will take a while to deplete that.

 

[ZCape35]

Thank you for that link, I read it all and understood most of it.
I’m surprised that my feeding is likely the biggest cause! I also see that I shouldn’t be overly concerned with numbers.

My main concern is that I still would like my Po4 in a good range for my SPS corals. How do others that feed frozen cubes (Hikari in my case) maintain low Po4 numbers?
If food is a big factor (which I now know) how does everyone do it?

 

[ZCape35]

I think I will try to cut back on the food by 50% and see how that affects Po4. Over the next few days.
I have 16 fish with 2 of them being 6” long Tangs. The rest are all medium to small.

Those 2 6” Tang
2 3” tangs
Couple clowns
Couple Anthia
5 Chromis
Royal Gramma
Lawnmower Blenny
Melanurus Wrasse
I was feeding 6 Hikari cubes and 1/2 sheet Nori daily. All food was eaten and gone in probably 30 seconds. I’ll cut back and see how that goes.

 

[jmichaelh7]

I think I will try to cut back on the food by 50% and see how that affects Po4. Over the next few days.
I have 16 fish with 2 of them being 6” long Tangs. The rest are all medium to small.

Those 2 6” Tang
2 3” tangs
Couple clowns
Couple Anthia
5 Chromis
Royal Gramma
Lawnmower Blenny
Melanurus Wrasse
I was feeding 6 Hikari cubes and 1/2 sheet Nori daily. All food was eaten and gone in probably 30 seconds. I’ll cut back and see how that goes.

I’m in the same boat brotha. How long did it take for rocks to stop leeching? It’s been a month and half I might pull the rocks today

 

[Superlightman]

not starve your fish because of your rock leaching phosphate. Tropic marin elimin phos rapid is a cheaper way than phosphate absorber to bring it down. Nopox is good for nitrate and phosphate, maybe it could also work.

 

[Randy Holmes-Farley Verified Community Expert]

not starve your fish because of your rock leaching phosphate. Tropic marin elimin phos rapid is a cheaper way than phosphate absorber to bring it down. Nopox is good for nitrate and phosphate, maybe it could also work.

In general, NOPOX isn't a good bet, IMO, to solve phosphate problems, and like all organic carbon dosing, is more geared to lowering elevated nitrate (or beign dosed for reasons unrelated to nutrients, such as generating food for filter feeders).

The Tropic Marin product is a brand of lanthanum. There are many brands that will essentially be equivalent and some may cost less than the Tropic Marin.

 

[Superlightman]

In general, NOPOX isn't a good bet, IMO, to solve phosphate problems, and like all organic carbon dosing, is more geared to lowering elevated nitrate (or beign dosed for reasons unrelated to nutrients, such as generating food for filter feeders).

The Tropic Marin product is a brand of lanthanum. There are many brands that will essentially be equivalent and some may cost less than the Tropic Marin.

well for me it seems to lower more the phosphate, I also use the product from zeovit which smell same vinegar. I think the most cheap and effective would maybe to use directly vinegar?

 

[Randy Holmes-Farley Verified Community Expert]

well for me it seems to lower more the phosphate, I also use the product from zeovit which smell same vinegar. I think the most cheap and effective would maybe to use directly vinegar?

I used vinegar only and thought it worked well for what I wanted. I personally do not see a reason to use commercial organic mixes.

The reason organics can drop nitrate more than phosphate is that denitrification is a process that consumes organics and nitrate, but not phosphate. There's no similar process that drops nitrate and not phosphate.

 

[ReefGeezer]

The rock will continue to leach P for a long time. Lanthanum chloride is the most efficient & cheapest method to reduce it. It's not a forever thing. You just use it until the rock has given up most of the phosphate it that bound to it. Besides the expensive aquarium hobby brands, pool supply houses & websites carry big jugs of it for cheap. There's plenty of threads showing how to employ it here on R2R.