Fun with Phosphates

[rworegon]

OK I have a 90 Gal mixed reef, 20 gal sump, 6 gal fuge with rock rubble and macro, oversized skimmer bla bla bla. System is about a year old. Here is the issue:

Phosphates have always been on the high side. Yes I probably overfeed. Water tests have always been pretty good. Nitrates are **** close to zero, no ammonia, alk runs between 8 and 9, sorry its an API test, Cal 440 to 460, Mag around 1400. These are what its been running on average over the past few months. Phosphates got as high as .35. I used some Kent Phosphate sponge and reduced it down to .25 while I waited for my BRS reactors to arrive. I got the reactors on line, one running GFO (3/4 cup to start) and carbon in the other. In 24 hours Phosphates went from .25 to .15. In the next 24 hours Phosphates went to .13. This is Hanna Checker.

This is my first reactor so I have no experience with running Gfo other than running Chemipure in the filter sock. So my question is, is it possible that the small amount of GFO I started the reactor with is already depleted? Should I run it for a couple more days and test again before worrying about changing it out? I know I don't want to completely eliminate Phosphates, or bring them down too quickly.

Looking for experience or suggestions.

Thanks.

 

[Reefing Madness]

If it hasn't taken anymore out of the system, I'd change it.

 

[rworegon]

Thats what I was thinking. Just didn't want to strip it out too fast.

 

[Reefing Madness]

System will stabilize pretty quick with it removed.

 

[rworegon]

Tested again last night and Hanna read .11. I would have changed it out last night but I needed the salt water I had mixed to do a water change in my 65 gal QT. Copper time is over for the tangs. I will mix more today. I just need some to flush the reactor of the fines. I run the ractors off a manifold and I need to replace the flush water with fresh saltwater.

 

[Reefing Madness]

 

[rworegon]

Well I tested again last night and phosphates actually climbed to .17. replaced the GFO and restarted the reactor. Can't wait till I get this stable.

 

[mcarroll]

Sounds like you are on the right track!

Just one or two suggestions since I didn't see anyone mention them.

Since you made your preference for over feeding known, why not consider scaling back your livestock just enough so you can still over feed, but without issues (or reactors)?

Doesn't sound like it would take much of an adjustment to balance things this way.

Also, it's possible the feeding itself might not be the issue. If enough of the by products are making it into your rocks and sand bed, they will definitely cause an issue like this. Use a powerhead or turkey baster on your rocks and swizzle a stick or your finger around in the sand (especially at the bases of rocks and under powerheads). If you see any detritus at all - even a faint tan color from the sand - you know what your issue is.

Let me know what you find!

-Matt

 

[rworegon]

I've already cut back on feeding a bit. I have to admit I haven't blasted my rockwork in a while. Thanks for the reminder. I run 2 mp-40's on opposite ends of a 4' tank so the flow is there. I just need to get the gunk up into the water column so it can go into the overflow. Been a while since I stirred up the sandbed too. I will to a bit of selective vacuuming at the next water change. I don't like to do too much stirring. I worry about the clams.

 

[MBG75]

You can test the phosphates coming out of the gfo reactor. If its lower than the tank phosphates, then the gfo is still working.

 

[mcarroll]

I've already cut back on feeding a bit. I have to admit I haven't blasted my rockwork in a while. Thanks for the reminder. I run 2 mp-40's on opposite ends of a 4' tank so the flow is there. I just need to get the gunk up into the water column so it can go into the overflow. Been a while since I stirred up the sandbed too. I will to a bit of selective vacuuming at the next water change. I don't like to do too much stirring. I worry about the clams.

It will only take a little stirring in 2-3 locations to determine if you have an issue. (You aren't trying to clean the sand bed here. Not the right approach - especially if there's an issue.)

-Matt

 

[rworegon]

Ok, if I do have an issue, what to do about it? If I stirr up the sand in a couple of places and I see the telltale cloudy mess, how would you suggest I go about dealing with it? My Pistol gets really PO'd when I start messing with the sand bed, especially around the base of the rocks.

 

[mcarroll]

I would remove the sand bed by siphoning during water changes. I'd remove no more than 1/4 at a time...you may have to avoid the shrimp's current area.

Your live rock should easily handle your filtration needs, so going bare bottomed except the shrimp area is one option. Fwiw, if they relocate during cleaning, remove their sand too - they'll technically be fine with shells and small rubble chunks as far as cave-building.

Putting new sand in - and how much - is completely optional.

-Matt

 

[rworegon]

OK, got them under control. Last nights testing showed .03 ppm Phosphates. Alk dropped a bit but have been manually dosing alk to handle that. Steady as she goes!

 

[Zero Nitrates]

OK, got them under control. Last nights testing showed .03 ppm Phosphates.

Great!