Questions for those running GFO

[Northstar24]

In early November, I purchased a GFO reactor and some of the high capacity GFO from BRS. I got it online, and after about 48 hours, I stopped getting the film algae build up on my glass, and the little bit of Cyano that I had on two of my rocks finally dissapeared. Approximately 3 weeks after setting this reactor up, I started noticing the film algae coming back, and the cyano has appeared on the same two rocks again.

After seeing this, I replaced the GFO in the reactor, I figured the first few changes would exhaust the media quickly because of the rocks holding phosphate and leeching it out. With the second round of GFO, I have not seen any decrease in algae, and it actually appears that the cyano has gotten worse

Is it normal to see rapid improvements when first starting GFO and then nothing after? I'm going to go broke if I have to change out this high capactiy GFO every two weeks, that stuff is not cheap. If that is the case, would I be better off using standard GFO for a while until all the stuff leeches out of my rock? Any idea on how long that would take?

I'm sure you'll all ask for feeding regimen and current water tests. I feed about a half cube of frozen every third day, and on one of the off days in between the tangs get some nori

As far as water parameters go:
Alk 9
Cal 400
Nitrates 0 (Obviously i have some nitrates or I wouldnt have algae, I get film growth on the glass, some cyano, and growth of caulerpa / chaeto in the fuge)
Nitrites 0
Ammonia 0

Water changes are 10% weekly

I have a brain coral and a duncan that were added about a month ago, and both are doing well, which is progress for me. Something in my well water was making it through my filters and into the tank (iron and phosphates I suspect) and it was causing a LOT of issues for me

 

[poksal]

Are you running a RODI filter set in your filtering system? It doesn't sound like it. If so, are you running the waste water tube at the bottom of the RO membrane canister? Also, sometimes people do not get the membrane pushed all the way into the RO canister and water bypasses the membrane... when this happens you will see the color of the DI material change quickly. You should not be getting iron and phosphate out your RODI.

If you do not have a RODI.. wow.. I'd make that my next investment and project!

YES, well water is often very high in iron and phosphates..... as well as can have several other heavy metals and elements.

 

[Northstar24]

I was running on well water previously, and the RO/DI unit and all of the lines were full of a rust colored buildup, which I can only assume is iron (what else is rust colored)

I trashed that RO/DI unit and bought a new one and hooked it up to my municipal water I've got a TDS of 2 before the DI resin, and 0 afterwards

That being said, I was using the water from the well for the first two years that the tank was set up. I never really could keep corals and I was having constant cyano issues. As it turns out, iron in the water will promote the growth of cyano. After I lost several fish in a short span I went through everything and determined that some sort of contamination was coming from the well water. I recently switched over to municipal water with a new RO/DI unit, and started running GFO in a reactor as well as a little carbon (not in the same reactor)

 

[poksal]

I run my GFO coupled to a carbon reactors when I think I need to. I never see any "instant" visual changes.. other than found through testing. ..shrugg.... But... I don't have a serious phosphorous problem.. I just run them mostly to make sure I don't have any stray chemicals still in my tank from when I had some bad rock.