Does PO4=orthophosphate? - Fertilizing

**IUnknown** · 09-08-2004, 02:52 PM

Quote:

Greg, I received your request today. First, are you looking for just the reactive phosphorus (orthophosphate) in your sample or the total (ortho & meta)? If you want total we need to look at a different kit. If you do want just ortho, the kit that you mentioned would work just fine. Accuvacs are used instead of sample cells and powder pillows. They are vacuum pressured ampoules that already contain the reagent in them. You submerge the ampoule in your sample breaking the glass tip and the ampoule fills with your sample due to the vacuum pressure. This is a very easy way to do your testing but ends up costing a little more per test. Please let me know if you have any further questions or if I can create a quote or place an order for you. Thanks!

I'm trying to figure out which kit I need. What is the PO4 that we measure?
thanks,
Greg

**IUnknown** · 09-08-2004, 03:06 PM

Ok, looks like ortho,
http://fins.actwin.com/aquatic-plant.../msg00317.html

plantbrain · 09-10-2004, 10:44 AM

Ortho is the only form a plant will use, the organic fraction often appears on a GOOD total PO4 test kit as about 0.1-0.2ppm of PO4, this makes many assume they have PO4 present, when the plants are limited and at 0.0ppm of available PO4.

I typically advise higher PO4 levels for this reason that get beyond any organic residual floating around

Regards,
Tom Barr