Insane po4 consumption

[troublemaker]

Any advice or input is appreciated.

Currently dosing 0.32 ppm of po4 per day and cannot get po4 above 0 for more than a day. use Hanna phosphate ulr to check and icp’s agree that it’s around 0.01
System is 500g, about 10 years old with 6 year old sandbed and pretty acro dominant. Guessing 250 lbs of rock, seeded with ocean rock. I feed about 200g of frozen food a week along with 20ish grams of dried coral foods a week. Skimmer is sized for a 250g and skims pretty dry. There are 14 fish, a lot of 5-7” tangs/foxfaces.
No contaminants noticed on icp’s.

 

[troublemaker]

Also forgot to add, alk comes mostly from kalk, ph is 8.5-8.8.

 

[Justfebreezeit]

Interesting dilemma.

You feed plenty of Nori?

 

[troublemaker]

Interesting dilemma.

You feed plenty of Nori?

Definitely interesting but hard to keep acros consistently happy when nutrients are this low.

Usually around 8 sheets a week. Soaked in vitamin-x from reefmoonshiners and selcon.

 

[Randy Holmes-Farley Verified Community Expert]

Phosphate reversibly binds to calcium carbonate surfaces. Once it gets very low (or high) it takes a lot of addition (or export) to change it.

What are you using to dose?

It may just take a lot more. Bare rock in a bucket can take up many ppm of phosphate.

 

[troublemaker]

Phosphate reversibly binds to calcium carbonate surfaces. Once it gets very low (or high) it takes a lot of addition (or export) to change it.

What are you using to dose?

It may just take a lot more. Bare rock in a bucket can take up many ppm of phosphate.

DIY trisodium phosphate, 32g/liter and I dose 32ml a day. I’ve been upwards of 20ml a day for the past year or more. Each ml should be about 0.01ppm po4 in 500 gallons

 

[Randy Holmes-Farley Verified Community Expert]

It is worth testing the kit, if you have not. Try a small amount in some new or old salt water and see if you get something close to the expected result.

 

[troublemaker]

It is worth testing the kit, if you have not. Try a small amount in some new or old salt water and see if you get something close to the expected result.

I did, and got 0.02

 

[Dan_P]

Any advice or input is appreciated.

Currently dosing 0.32 ppm of po4 per day and cannot get po4 above 0 for more than a day. use Hanna phosphate ulr to check and icp’s agree that it’s around 0.01
System is 500g, about 10 years old with 6 year old sandbed and pretty acro dominant. Guessing 250 lbs of rock, seeded with ocean rock. I feed about 200g of frozen food a week along with 20ish grams of dried coral foods a week. Skimmer is sized for a 250g and skims pretty dry. There are 14 fish, a lot of 5-7” tangs/foxfaces.
No contaminants noticed on icp’s.

Would you comment on photosynthetic organism growth in your system? Macro and micro algae, cyanobacteria, etc.

 

[Randy Holmes-Farley Verified Community Expert]

I did, and got 0.02

What value were you expecting to get? That value might be fine if you expected 0.02 ppm and not fine if you expected 0.2 ppm. :)

 

[troublemaker]

What value were you expecting to get? That value might be fine if you expected 0.02 ppm and not fine if you expected 0.2 ppm. :)

I believe Red Sea salt should be less than 0.03, so it’s expected. And icp matches up as well.

Would you comment on photosynthetic organism growth in your system? Macro and micro algae, cyanobacteria, etc.

Cyano in a new tank that was added 5 months ago but is clearing up as I dose more po4. Have a smallish macro algae in an anemone tank that I can definitely trim. Bubble algae issue that is mostly cleared up at this point. Glass gets a green film in the oldest tank in the system in about 3 days, but not as bad in the other 4 tanks.

Some acros are starting to look pale and have reduced polyp extension as time goes on, with a couple losses.

 

[Dan_P]

I believe Red Sea salt should be less than 0.03, so it’s expected. And icp matches up as well.


Cyano in a new tank that was added 5 months ago but is clearing up as I dose more po4. Have a smallish macro algae in an anemone tank that I can definitely trim. Bubble algae issue that is mostly cleared up at this point. Glass gets a green film in the oldest tank in the system in about 3 days, but not as bad in the other 4 tanks.

Some acros are starting to look pale and have reduced polyp extension as time goes on, with a couple losses.

Is the 500 gallon system five interconnected aquaria, one of which is new?

 

[Randy Holmes-Farley Verified Community Expert]

I believe Red Sea salt should be less than 0.03, so it’s expected. And icp matches up as well.


Cyano in a new tank that was added 5 months ago but is clearing up as I dose more po4. Have a smallish macro algae in an anemone tank that I can definitely trim. Bubble algae issue that is mostly cleared up at this point. Glass gets a green film in the oldest tank in the system in about 3 days, but not as bad in the other 4 tanks.

Some acros are starting to look pale and have reduced polyp extension as time goes on, with a couple losses.

That’s not the sort of test I was suggesting as a standard.

 

[troublemaker]

Is the 500 gallon system five interconnected aquaria, one of which is new?

Yes, it is all one system tied together, and has two new tanks. First 200g is 10 years old, another 100g is 20 months old, and the last 200g was added 5 months ago.

 

[troublemaker]

That’s not the sort of test I was suggesting as a standard.

Sorry, I’ve tested compared to icp’s and freshly made saltwater. Are you suggesting adding some trisodium phosphate to a sample of tank water and seeing if test comes close to that?

 

[Dan_P]

Yes, it is all one system tied together, and has two new tanks. First 200g is 10 years old, another 100g is 20 months old, and the last 200g was added 5 months ago.

Do you think Randy’s idea that aragonite is adsorbing the phosphate might be happening in the new systems and bringing down the entire system’s phosphate?

 

[troublemaker]

Do you think Randy’s idea that aragonite is adsorbing the phosphate might be happening in the new systems and bringing down the entire system’s phosphate?

Possible but they are both bare bottom, and the 100g has no rock. The most recent 200 gallons has new rock, but issue predates that. I think I’ll just keep dosing and see what comes of it. Will also try to see if I can make stock solution to find testing error. Thank you for help.

 

[Randy Holmes-Farley Verified Community Expert]

Sorry, I’ve tested compared to icp’s and freshly made saltwater. Are you suggesting adding some trisodium phosphate to a sample of tank water and seeing if test comes close to that?

That's what I was suggesting, but if you have compared to a quality, filtered icp (such as Oceamo does), that's also fine.

 

[Randy Holmes-Farley Verified Community Expert]

Possible but they are both bare bottom, and the 100g has no rock. The most recent 200 gallons has new rock, but issue predates that. I think I’ll just keep dosing and see what comes of it. Will also try to see if I can make stock solution to find testing error. Thank you for help.

Is the 100 g a reef tank? Not really seen one with no rock or sand.

 

[troublemaker]

That's what I was suggesting, but if you have compared to a quality, filtered icp (such as Oceamo does), that's also fine.

I’ll do this test as well, but my Hanna test normally reads slightly above oceamo icp-ms.

Is the 100 g a reef tank? Not really seen one with no rock or sand.

It is a frag/grow out tank so mostly frag racks, tiles, and some detritus that settles on the bottom.