Phosphate 0 problem?

[Danh Ngo]

my hannah checker (low range, not Ulr) alway show 0 phosphate. I’m running GFO (1/2 recommended amount). Could 0 phosphate make my acro unhappy? How to raise it up ?
No3 reading at 0.75
Vinegar dosing 1.5ml daily,
Dosing AA
Another thing to mention, I have 1 mille frag, doing well with polyps extend, and 1 mille colony was damaged by a crab- this one polyps do not extend much

 

[hijinks7]

Yes it seems the general thinking these days if you need a small bit of phosphate in the water.

I'd just remove the GFO and see what happens and keep adding small amounts till you hit your sweet spot

 

[homer1475]

If you have 0 PO4, why would you be running GFO? And yes the lack of nutrients will starve the coral to death, even if your manually feeding it.

Ask me how I know.....

I would also recommend the ULR kit. For a couple years I was testing 0 on the low range, got the ULR and I do indeed have PO4, albeit a slight amount, but it's still there. And whats recommended cannot be tested for on the regular low range kit.

 

[chipmunkofdoom2]

I would use the tank as your guide. As a general rule, the hobby seems to be discovering that no dissolved nitrates and phosphates can be a problem. But, keep in mind that the phosphates and nitrates in the ocean measure in the low parts per billion. If you're feeding small particulate food often, like the corals receive in the wild, then you may not need much dissolved nitrate and phosphate.

It seems like you have a pretty good handle on things. If the corals are healthy and have good color, I personally wouldn't change anything. Maybe try reducing the GFO and see how your tank responds. If you see an increase in coral health, stick with it. If you see an increase in nuisance algae growth maybe go back to where you were.

 

[Danh Ngo]

If you have 0 PO4, why would you be running GFO? And yes the lack of nutrients will starve the coral to death, even if your manually feeding it.

Ask me how I know.....

I would also recommend the ULR kit. For a couple years I was testing 0 on the low range, got the ULR and I do indeed have PO4, albeit a slight amount, but it's still there. And whats recommended cannot be tested for on the regular low range kit.

I have been running GFO for a year. Could it be the case that GFO reduce Po4 to 0?

 

[Danh Ngo]

I would use the tank as your guide. As a general rule, the hobby seems to be discovering that no dissolved nitrates and phosphates can be a problem. But, keep in mind that the phosphates and nitrates in the ocean measure in the low parts per billion. If you're feeding small particulate food often, like the corals receive in the wild, then you may not need much dissolved nitrate and phosphate.

It seems like you have a pretty good handle on things. If the corals are healthy and have good color, I personally wouldn't change anything. Maybe try reducing the GFO and see how your tank responds. If you see an increase in coral health, stick with it. If you see an increase in nuisance algae growth maybe go back to where you were.

I feed reef roid twice a week, and feed fishes once a day

 

[Danh Ngo]

If you have 0 PO4, why would you be running GFO? And yes the lack of nutrients will starve the coral to death, even if your manually feeding it.

Ask me how I know.....

I would also recommend the ULR kit. For a couple years I was testing 0 on the low range, got the ULR and I do indeed have PO4, albeit a slight amount, but it's still there. And whats recommended cannot be tested for on the regular low range kit.

For the ULR, I think the reading is not in ppm, right? Have you ever get reading like 0.01-0.02 from the Low rang checker - not ulr

 

[homer1475]

Yes it is not in PPM, but if you to hanna's website they have a conversion table you can download, and there is a simple calculation to convert it. But I just downloaded the table and printed it out.

Yes I have gotten a 0.01 from the low range. If i remember correctly the margin for error at such low ranges with the regular low range was something like .05 to 1.0 or something like that. It has a pretty bad accuracy range for low ranges we usually see in our tanks.

 

[cracker]

BRS have a video on the comparison of the 3 test kits,ULR & low range Hanna checkers & another brand. These were all compared with a high end,lab grade instrument. You might it find interesting.

 

[Greenstreet.1]

With the po4 checker is 0 really 0 ?

Look at the error range on the ulr

 

[rkpetersen]

If your phosphate is truly 0 you should not have any GFO running and I wouldn't recommend carbon dosing is that circumstance either. Techniques that reduce nutrients, in the absence of detectable nutrients, aren't generally a good idea. However, there is a difference between natural nutrient reduction techniques, like algae cultivation, vs artificial techniques like GFO; artificial techniques are quite capable of driving your phosphorus level down to 0.00, not even detectable on ICPOES testing; algae cultivation will usually leave some phosphorus in the water, even if the level is very low and undetectable by some hobbyist tests.

I also recommend the ULR phosphorus checker; the difference to your corals between an ULR reading of 0 and a reading of 10 can be substantial. Converting the displayed phosphorus level to the phosphate we're more familiar with is easy, you don't need tables, you can do it in your head. Multiple the phosphorus value by 3 and move the decimal point over 3 places. ULR checker reading of 10 phosphorus; x3 = 30; move decimal place = .03 phosphate.

 

[homer1475]

I knew there was some simple math to convert, I just couldn't remember what it was.

I just found it easier to print out the table and look up the number on the sheet.

 

[rkpetersen]

For the ULR, I think the reading is not in ppm, right? Have you ever get reading like 0.01-0.02 from the Low rang checker - not ulr

Yes, it will sometimes give you a measurement like that. But it's more likely to give you a false reading of 0 when the ULR checker reads 4, for example.

 

[rkpetersen]

I knew there was some simple math to convert, I just couldn't remember what it was.

I just found it easier to print out the table and look up the number on the sheet.

Yeah either way is fine. After awhile using phosphorus, I don't even think in terms of phosphate anymore. I shoot for a phosphorus in the 5-15 ppb range.

 

[Danh Ngo]

I just order ULR checker from brs, will check on that before making any changes to the system