Phosphate question

[Engloid]

I absolutely hate the Salifert test kit for phosphate. I can mix up the reagents and water, put it on the card for comparison, and it seems that if I move it an inch, thanges in light and shadows can drastically affect the way I interpret the results. I can hold it one way and it shows 1ppm, give slight movement under the light and show .1. It's as if I can move it and get any result I want to show. I think I am going to have to get a meter and ditch this crappy kit.

Anyway...best I can figure, my phosphate is showing .5ppm...which I know is high. Even when I use GFO, it seems like I never get any reduction. Out of curiosity, and for comparison, I tested some of my tap water and read ZERO!! hmmm.. Opinions?

With 0ppm phosphates in the tap water, it is tempting to bypass the RO and just try tap water for a while.

 

[vasinvictor]

Your tap water will have other stuff in it that is not desirable. You can get a cheap Hanna meter for less than $50.

 

[EvilMel]

I don't measure phosphate because it can be problematic even when it's not registering on a test kit.

Also, sounds like your kit isn't working.

 

[caudill187]

I battled phosphate for a long time in my first tank and finally changed the substrate, which eliminated the problem. How much GFO do you run, how big is your tank, and how often do you change it?

I wouldn't use the tap water.

 

[Engloid]

I run probably 1/2 gallon of GFO at a time, and don't change it like I should...and honestly don't plan to. I want to fix the problem, rather than pay money to absorb it. Not only that, but even putting in fresh GFO doesn't seem to drop the phosphate at all.

I think I will slowly phase out the bit of lava rock I have in the tank. I may take a piece out, soak it, rinse it, dry it, etc... then put it in with some plain RO water, and see if it leeches out phosphate.

 

[TriMax]

sounds like a plan.

 

[EvilMel]

...and let me add: I hate all test kits. hah hah.

Spencer, back when I was at the reef Randy said something to me about lava rock leeching out SOMETHING but I cannot remember what it was. I thought it was metals, for some reason but maybe it was phosphate. Also, let me ask, did you get a bunch of their dry base rock by any chance? That white stuff that was in the boxes near the vats.

 

[TriMax]

Spenser

I a BRS Hanna Checker Phosphate PO4 Colorimeter that you can borrow if you want.

Eddie

 

[EvilMel]

What's the lowest value that thing will read, Eddie?

 

[cee]

There have been bad reviews on the Hanna cheaper photometers. Try to get one of the Deltec/Merck kits cause it goes down to 0.008 but I'm not sure it is still available. Most others are garbage. Also, the phosphate is likely trapped in the LR so the water parameters don't necessarily reflect the phosphate available to nuisence algae.

 

[EvilMel]

Also, the phosphate is likely trapped in the LR so the water parameters don't necessarily reflect the phosphate available to nuisence algae.

That's a good point. In addition, if there is detritus on the rock (as happens when you don't have enough flow and/or don't blow off your rocks) it can degrade on the rocks, creating micro-environments of higher nutrients that may slowly leech out into the water.

Under all my cyanobacteria on my rocks lies a mat (biofilm) of degrading crud, which is the major reason why the cyano irritates me...not just because it looks really red in the tank.