For the last 6 weeks or so I have had an increasingly worsening problem with the green hair algae. I think the massive die off of flatworms during my Levamisole disaster started it by releasing all kinds of tasty nutrients into the water. I've been running more than sufficient amounts of GFO (from BRS), but my PO4 levels stayed between 0.06-0.09 as measured by the Hanna PO4 meter. I wanted to figure out where the PO4 was coming from as I currently have only 2 clowns in my 150 gallon tank and they get fed once per day to every other day with the small Hikari Seaweed Extreme pellets that I basically drop down one by one to make sure they get eaten immediately (for some reason my clowns won't eat them off the sand bed). I didn't think overfeeding was a problem. I had bought a couple of boxes of Hanna reagent and started a little investigation. Here are my findings:
1. Even though the TDS meter shows 0 TDS in my RO/DI water, Hanna Checker shows between 0.00 - 0.05 ppm (water is taken directly from the RO/DI unit and test tubes get flushed with the tested water 3 times). Obviouosly, the TDS meter doesn't have enough sensitivity to register such a small (but significant amount of PO4 in RO/DI water). I have found that packing the resin very tightly makes a big difference and increases contact time betwen the resin and water. PO4 don't get removed by the pre-filters and are only partially removed by the membrane leaving the resin to do most of the PO4 removal).
2. The grey Rubbermaid Brute trash cans release phosphates into the RO/DI water. After sitting in the container for a few days, my RO/DI water reads 0.09-0.12 of PO4. The 5 gallon white water jugs with a handle on top (sold by many LFS) don't leech out any PO4 as far as I can tell.
3. Seachem Marine Buffer is LOADED with phosphates. This is probably the major contributor to my GHA outbreak. I have been dosing the SMB for over a month to keep dKH between 9-10 by adding ~3 teaspoons per 5 gallon of top off RO/DI water (5 gallon lasts about 2 days). Checking the water with SMB showed phosphates between 1.90-2.35 ppm !!! Last week I switched to baked baking soda dissolved in RO/DI water (2 1/4 cups per gallon) and have been adding 30cc of the solution to my 5 gallon top off jugs. This have made dKH virtually unchanged for 1 week. The solution tests negative for any phosphates even in its concentrated form.
4. Hanna Checker has a resolution of 1 ppb (0.001 ppm) 0.01 ppm with accuracy of 10 ppb (0.01 ppm) 0.04 ppm per the manufacturer's website. R2R forum has several threads dedicated to Hanna Phos Checker and the accuracy seems to be much lower (+/- 0.03 ppm). Maybe they have improved the checker since its original release...
5. RowaPhos appears to be more effective in removing PO4 form water than the (regular) GFO from BRS. I replaced 2.5 cups of GFO with 350 grams of RowaPhos in my reactor (155 gallons of circulating volume in my system) 4 days ago and the phosphates have dropped form 0.07 to 0.03 ppm which is the lowest they have ever been. I have also added 150 grams of RowaPhos to my Rubbermaid RO/DI water storage tank to remove any phosphates form the water before I add it to my aquarium.
...to be continued.
Edited by Carlsson - March 22 2014 at 2:28pm