PO4 off the charts~

Re: PO4 off the charts~

You didn't mention CO2. Do you use pressurized CO2? Your KH and pH indicate you have around 20 ppm of CO2, but you probably have a lot less, so try jacking it up if you have it. The lack of or very low CO2 could cause both nitrates and phosphates to build up if you are dosing per EI recommendations, because plants won't be using it up.

 

Re: PO4 off the charts~

How do you know you can trust your PO4 test kit? From what I read, those are not accurate without very careful calibration.

 

Re: PO4 off the charts~

That is hardcore but unlikely. Contaminated Eco eventually stops leeching PO4 yeah? If you can do water changes to limit that, your high PO4 from tap doesn't matter. It is mind numbing, but the article linked here explains this: http://www.barrreport.com/forums/showthread.php?t=1074

Think of the PO4 introduced from tap as a dose, and whatever is leeched by the Eco as another dose. You could probably measure Eco's contribution (and if you have a contaminated bag) by putting an appropriate amount of substrate in RO/DI and measure the increase after a week, dependent on the accuracy of the test(s).

But if you have pearling now, that's good yeah? In my mind, I think increasing CO2 is fundamentally the same as increasing N to compensate for high PO4, only much more effective.

Just thoughts.

 

Re: PO4 off the charts~

I would do that fwiw. After the water change at the end of the week, I'd start dosing NO3 to moderate targets again.

 

Re: PO4 off the charts~

Just out of curiosity, if the PO4 were at 3 or 4 ppm, what problems might be expected?

Would high nitrate levels have any effects on that?

Bill

 

Re: PO4 off the charts~

How does your tank look? Algae?

I had this problem and brought down PO4 with water changes. Everything is doing much better now.

Here's a good article on the relationship between to two.

http://www.xs4all.nl/~buddendo/aquarium/redfield_eng.htm

Keith,

 

Re: PO4 off the charts~

I have tested the Hagen Nutrafin Phosphate test kit for use with dosing Seachem's Flourish Phosphorus. And the test kit read exactly what I expected it to. I mixed some bottles of Tap water, and some bottles distilled water with a small measured dose of Flourish Phosphorous. I then used the test kit to measure PO4 levels in each bottle.

The reason for using distilled water was to verify that the test kit read correctly without any contaminates messing up the results. The second test using tap water was to verify that there were no contaminates in my water source that messed up the measurements. The measurements of both water sources agreed well within acceptable levels. My water straight out of the tap has undetectable levels of PO4.

When I later switched to using Greg Watson's powdered KH2PO4, I dosed a measured amount into a newly set up tank and measured the PO4 level using the same test kit. Again the test kit read the amount I expected it to.

Lately I have been using the EI method, but I did use my calibrated test kits to check my math and verify the amounts I came up with to dose for a 180Gal tank were correct. Tom's dosing examples in his EI articles didn't list doses for very large tanks.

 

Re: PO4 off the charts~

Yeah, I've heard that PO4 doesn't cause algae. But its starting to be obvious to me that some sort of balance needs to be reached. My tank is 2.5 months old, and every time it starts two look great I think to myself " now is the time to increase light and do full EI. So far the algae loves my thinking I,m now looking to co2 as the limiting factor. My hardness is about 5.5 and my PH drops to around 6.8 every evening. I'm using a rex reactor and can't seem to dissolve enough co2 for my 135 gallon tank. So in my case I think the high PO4 Is a case of the plants are being limited by my CO2. So back to the drawing board!