Running gfo but phos keep rising

[bglegs]

I started running gfo reactor.First before before using I got a reading of .12 (hanna ).I ran for reactor for 48hrs and checked level .03 so I thought I was on the right path so I changed out again and checked the reading was higher.I have been changing out gfo every 48hrs for two weeks.My recent reading was .23.I"m wondering if the hanna meter is off.Although I checked ro water and that reads .00. I recently replaced all my ro/di filters including two membranes.I don't have an algae problem so I'm really confused.Could the live rock be leaching phos.Any advice will be appreciated..

[fishchef]

I have a Checker also and recently I used the other vial it came with. Wow, what a crazy high reading! So then I did a second test with the other vial. Now I got a .02 instead of .65.The lower reading was more in line with the LFS. My results have always compared with my friends Lab Hanna at his LFS. He told me to use the vial that mostly compares in results to his unit. Now my tests are more consistent. I've had my Checker for almost 2 years and I knew the cleanliness of the vials was critical. The shape of the glass also effects readings. Probably why you get two.

[ColaAddict]

Phosphate testers are known for being very unreliable. The best thing you can do is a visual check of your aquarium, if there is no algae growing, then you are good. If you have SPS and they are showing growth, then you are also good.

[fishchef]

Visual is tough. I need some kind of guide. Switching out GFO too often can be expensive and bad for your corals. Yes, PO4 can be absorbed into your LR if you haven't been using it and then released back into your system. My local water Guru says no more than evey 3 weeks. It took me over a year to get my PO4 down to below .55 changing the GFO every 3-4 weeks. I didn't have algae either, just that pesty cyno. The aftermath of using a poorly designed test kit. Phosphate is a building block of coral growth and stripping it out to quickly can damage health.