PO4 !!!! So frustrated

[BantyRooster97]

So I have been battling high PO4 for almost 2 months now. I made a bone head move & added some old rocks & crushed coral to my tank & it was loaded with PO4. I have since removed it but my #'s just won't stay down.

Friday last week it was .07 & had been there for about a week, not moving much. Today I test & it is .11! The only thing I have done is a small 5gal water change (I've already tested a new batch if water, 0 PO4, so that isn't it) & yesterday I fed 2 cubes of frozen food.

Would that have enough PO4 in it to make it raise .04 pts?

thx

 

[Brew12]

So I have been battling high PO4 for almost 2 months now. I made a bone head move & added some old rocks & crushed coral to my tank & it was loaded with PO4. I have since removed it but my #'s just won't stay down.

Friday last week it was .07 & had been there for about a week, not moving much. Today I test & it is .11! The only thing I have done is a small 5gal water change (I've already tested a new batch if water, 0 PO4, so that isn't it) & yesterday I fed 2 cubes of frozen food.

Would that have enough PO4 in it to make it raise .04 pts?

thx

Quantifying increases in PO4 is challenging. For instance, when you added the old rocks it raised the amount of PO4 in your water. Some of that PO4 was also absorbed by all of the rock in your tank. Even though you removed the worst of the rock, you need to let the PO4 in the remaining rock leach back out.

Fortunately, 0.11 shouldn't be too bad. It is something you will have to monitor until your system balances back out. Running GFO may be a good option for you, too.

 

[Jet915]

My initial test (hanna) test was 0.31. I had mostly softies and everything grew fine. I was planning on adding sps, so I got gfo/carbon dual reactor and now my phosphate is between 0 and 0.1. If it hits 0.1 or higher, i change the cartridge.

 

[BantyRooster97]

I’ve been trying to keep it below .1 and really hoping it would drop to .05.

I thought about running carbon or gfo but I don’t want to strip the water too fast. The few remaining sps I have are hanging in there and don’t want to shock them.

 

[Brew12]

I’ve been trying to keep it below .1 and really hoping it would drop to .05.

I thought about running carbon or gfo but I don’t want to strip the water too fast. The few remaining sps I have are hanging in there and don’t want to shock them.

I always recommend running carbon, but I understand your concern with GFO. First time I used GFO I killed every coral in my tank. Slow changes are best!

I'm not sure how high your PO4 was before you pulled the old rock back out, but your tank shouldn't rise above that number unless you are adding more PO4 than your tank is consuming.

 

[BantyRooster97]

PO4 got to .25 before I caught it (Stuff started to die). My mistake was going out & buying PO4 remover & dropping it super fast to below .1 in like 48 hrs. Then more stuff started to die.

Since then I removed all the bad rocks. I am guessing the other rocks absorbed the phosphate & is now releasing it. Just don't know why it would have released it so quickly in the past week.

How much PO4 is in frozen food?

 

[HolisticBear]

Friday last week it was .07 & had been there for about a week, not moving much. Today I test & it is .11! The only thing I have done is a small 5gal water change (I've already tested a new batch if water, 0 PO4, so that isn't it) & yesterday I fed 2 cubes of frozen food. Would that have enough PO4 in it to make it raise .04 pts?

Food is a major contributor to PO4.

PO4 content varies greatly depending on the food, but if you compared a reading in the morning before feeding and then another reading 3h after feeding, the food could easily make a 0.04 difference.

A huge quality of life improvement for me was to always test PO4 at the same time. For me, I test it before the first feeding of the day. That's probably the low point of PO4 in my tank. Only comparing readings from that period, made the numbers more consistent and easier to "dial in".

Randy has this article on phosphates in food, look at the some of the numbers: https://www.advancedaquarist.com/2012/3/chemistry

EDIT: Gross generalization, but the higher quality foods like LRS probably have a lower phosphate concentration that the poor quality foods. So besides reducing amount, changing brands/quality could help.

 

[jda]

Aragonite can be a huge reservoir for PO4. When you put the sand and rock it, it probably release a bunch to equilibrium with the water. This can happen fast. Then, the rock that you have soaked some up, lowering the water level and thus releasing more from the old rock. This can happen fast too.

Slow an consistent treatment with GFO is fine. Do not drop it too fast. It is possible that you might need gallons of GFO and that it might be exhausted in a few hours or overnight. What happens is that you put some GFO on the tank, tankwater is very low after a day, or so. When you take the GFO off, or it gets exhausted, then the PO4 will climb right back up to where it was (almost).