Po4 reading 0 wtf really?
- Thread starter 09bumblebee
- Start date
IME the Hanna HI-713 is very inaccurate. I too would get results all over the board from .00 to .08 and such test after test. At the low ranges we test for I would recommend the HI-736. It measures ultra low range phosphorous in the PPB. You just take the result number and multiply it by 3.044 and then divide that number by 1000. It has been consistent for me every time, test after test, even right after each other. IMO the 713 is junk for low range testing.
Also, what is your reasoning in keeping PO4 at .04? I know personally I like a measurable amount of phosphate to keep my macros growing but with a coral only system I am not sure there is a benefit. NSW is typically ~.005. Most systems that run GFO and change out when exhausted never have a measurable amount of PO4 without issue. I know we run GFO on all of our maintenance accounts and change regularly without issue and almost all of our systems have a 0 reading for PO4 at any given point.
Also, what is your reasoning in keeping PO4 at .04? I know personally I like a measurable amount of phosphate to keep my macros growing but with a coral only system I am not sure there is a benefit. NSW is typically ~.005. Most systems that run GFO and change out when exhausted never have a measurable amount of PO4 without issue. I know we run GFO on all of our maintenance accounts and change regularly without issue and almost all of our systems have a 0 reading for PO4 at any given point.
Because everyone tells me that po4 below .04 can be detrimental to the system and corals can be affected by that low of po4. Chris at AA experienced this in his frag system. The corals started loosing color and stony's lost PE. I'm no expert in levels nor have I experienced this but this is just what I've been told.
I know the Hanna Calcium checker is a complete nightmare as well....the Hanna PO4 seems to be ok for me. But you make a good point about the PO4. I've been told by many people around here store owners etc that these zoas/palys etc like a tiny measurable amount of PO4 in the system .03 to .01. I had an experience where I left my fuge light on 24hrs for a few weeks and accidently eliminated all the "measurable form" of PO4 and in doing so caused a slow mini tank crash where I lost lots of zoas....but maybe not afterall. So how does everyone run their tank? Do u keep Measurable amounts of PO4 or do u use GFO to keep it low or at 0?
*Measurable Form of Phosphate is inorganic orthophosphate
Aquarists can readily test for inorganic orthophosphate using a standard aquarium phosphate test kit, but testing for organic phosphorus compounds is considerably more tedious. http://reefkeeping.com/issues/2006-09/rhf/index.php
*Measurable Form of Phosphate is inorganic orthophosphate
Aquarists can readily test for inorganic orthophosphate using a standard aquarium phosphate test kit, but testing for organic phosphorus compounds is considerably more tedious. http://reefkeeping.com/issues/2006-09/rhf/index.php
Here is a good read:
http://reefkeeping.com/issues/2006-09/rhf/index.php
And another:
http://www.advancedaquarist.com/2002/4/chemistry
IIRC noticeable inhibition of calcification starts around .01ppm PO4 and the inhibition drastically increases as PO4 levels rise. In layman's terms, the more phosphate you have in your system the slower your stony corals will grow.
The train of thought is with zoanthids softies and some LPS is that they prefer "dirtier" water. IMO I think most confuse dirty with elevated nutrient levels where higher NO3 & PO4 are generally acceptable. The truth of the matter is that these organisms can tolerate higher levels but I believe they don't necessarily thrive or require this level. I believe dirty water needs to be looked at as having a higher DOC and/or a healthy microfauna population, not increased nutrient levels. Also, like anything saltwater related these animals are very sensitive to change and if they are used to being in elevated nutrient levels then a sudden drop can cause harm, hence why it is recommended to slowly start GFO and ramp up gradually so you dont drop your levels too fast. I am not aware of any studies that show a need for a PO4 level greater than .01 for reef invertebrates, if there is one I would love to read it
IME the most colorful reef home aquaria I have seen keep their nutrient levels unmeasurable. Not only does this keep the zooxanthellae in check it also helps keep nuisance algae at bay. I have also witnessed this with my home aquarium. When my PO4 levels rise above .03-.04 I notice my SPS starting to brown out.
To answer your question coloagro - I change out my GFO every 2 weeks. After 1 week I get a 0 reading for PO4. After week 2 I strive for it to be .001-.02 but sometimes it jumps up to .03 if I am not consistent with my feedings or I just trimmed a bunch of macros back. I only care to have a reading >0 because of my macro algaes. If I didn't have macros I would probably use more GFO at a time, change it out less and strive to keep my PO4 0 at all times. When my PO4 bottoms out I have not noticed any ill effects with any of my corals and my zoas grow just fine.
btw, if you are using GFO as directed its almost impossible not to bottom out your phosphate unless you are really overfeeding or have a new system with Pukani rock which is known to leach phosphates into a system, then your GFO will exhaust very rapidly. GFO is VERY efficient at binding phosphate from the water column.
Just my 2 cents.
http://reefkeeping.com/issues/2006-09/rhf/index.php
And another:
http://www.advancedaquarist.com/2002/4/chemistry
IIRC noticeable inhibition of calcification starts around .01ppm PO4 and the inhibition drastically increases as PO4 levels rise. In layman's terms, the more phosphate you have in your system the slower your stony corals will grow.
The train of thought is with zoanthids softies and some LPS is that they prefer "dirtier" water. IMO I think most confuse dirty with elevated nutrient levels where higher NO3 & PO4 are generally acceptable. The truth of the matter is that these organisms can tolerate higher levels but I believe they don't necessarily thrive or require this level. I believe dirty water needs to be looked at as having a higher DOC and/or a healthy microfauna population, not increased nutrient levels. Also, like anything saltwater related these animals are very sensitive to change and if they are used to being in elevated nutrient levels then a sudden drop can cause harm, hence why it is recommended to slowly start GFO and ramp up gradually so you dont drop your levels too fast. I am not aware of any studies that show a need for a PO4 level greater than .01 for reef invertebrates, if there is one I would love to read it
IME the most colorful reef home aquaria I have seen keep their nutrient levels unmeasurable. Not only does this keep the zooxanthellae in check it also helps keep nuisance algae at bay. I have also witnessed this with my home aquarium. When my PO4 levels rise above .03-.04 I notice my SPS starting to brown out.
To answer your question coloagro - I change out my GFO every 2 weeks. After 1 week I get a 0 reading for PO4. After week 2 I strive for it to be .001-.02 but sometimes it jumps up to .03 if I am not consistent with my feedings or I just trimmed a bunch of macros back. I only care to have a reading >0 because of my macro algaes. If I didn't have macros I would probably use more GFO at a time, change it out less and strive to keep my PO4 0 at all times. When my PO4 bottoms out I have not noticed any ill effects with any of my corals and my zoas grow just fine.
btw, if you are using GFO as directed its almost impossible not to bottom out your phosphate unless you are really overfeeding or have a new system with Pukani rock which is known to leach phosphates into a system, then your GFO will exhaust very rapidly. GFO is VERY efficient at binding phosphate from the water column.
Just my 2 cents.
All my corals were used to having po4 higher around 1 yes it was high dropping it to .04 over the last month I noticed some color change and left it at .05 until everything adjusted I've since dropped it to .03 and am seeing great results in all my corals. I do not run gfo at all just dose the red sea. Over the next few weeks I'll continue to drop to .01 to see what happens.