Inconsistent Phosphates

[straightrazorguy]

I've been battling high phosphates ever since starting the current tank (18 months ago). I bought the whole setup from another reefer, who (I believe) neglected it for months. Not knowing any better, I used everything: his rock, his sand, etc. When I first started it, in Nov 2012, the phosphates were over 1 ppm. Over time I brought them down to below 0.1 ppm, by keeping to a rigorous water changing schedule and running ROWAphos.

What irritates me is the swings in phosphate levels that I noticed over time. Below is a table showing the results over the past couple of months. I test using a Hanna Colorimeter.
*



DATE Phosphate Levels
13-Mar-14 0.15

15-Mar-14 0.17

16-Mar-14 0.11

18-Mar-14 0.1

21-Mar-14 0.08

25-Mar-14 0.12

27-Mar-14 0.13

30-Mar-14 0.13 Changed ROWAphos 2-Apr-14 0.31

3-Apr-14 0.08

6-Apr-14 0.04

10-Apr-14 0.06

15-Apr-14 0.09 Changed ROWAphos 17-Apr-14 0.3

20-Apr-14 0.1

22-Apr-14 0.3

24-Apr-14 0.1

29-Apr-14 0.06

30-Apr-14 0.05 After Shanging ROWAphos 4-May-14 0.06

7-May-14 0.48


I am totally puzzled. Any ideas/suggestions?

[straightrazorguy]

I forgot to mention I've had a refugium full of macroalgae and a turf algae scrubber for months. I also started running biopellets on April 1 and have been dosing kalk automatically since January. I don't have a high bioload (6 2-3 inch fish in a 55 gal with a 33 in-line refugium).

[Ryanerickson]

Phosphate test kit inconsistent maybe ?

[gregzz4]

Sounds like possibly the LR you got with the setup is packed and leaching - Old Tank Syndrome

You may want to consider buying some replacement LR, cure/cook it in a tub until it's clean, and then swap it all
Then you can cure the old LR and sell it

A Guide - Live rock; Curing & Cooking, and Tank Cycling

[toytech]

Might want to change out the sand too , could be full of crud . I reused my sand and my skimmers been pulling nasty gunk for 5 months now with no bioload.

[gregzz4]

Originally Posted by toytech

Might want to change out the sand too , could be full of crud . I reused my sand and my skimmers been pulling nasty gunk for 5 months now with no bioload.

+1
I missed that part

[mark]

extremes can probably throw out as a botched test, then device is only good for +- 0.04ppm

[straightrazorguy]

Originally Posted by toytech

Might want to change out the sand too , could be full of crud . I reused my sand and my skimmers been pulling nasty gunk for 5 months now with no bioload.

I'm about to do an upgrade, and I will be replacing the sand.

Still, has anybody encountered this level of inconsistency? From 0.05 to 0.5 within a couple of weeks? And then back to below 0.1 ppm?

[Maverick00]

I know people on here that love the phosphate hanna checker but Ive always had varying results when using it. May not be whats going on here but it annoyed me to the point where i dont use it anymore. Im also battling a phosphate issue and started losing some of my sps after I hooked up a GFO Reactor. Frustrating as hell.

[Masonjames]

Originally Posted by straightrazorguy

I'm about to do an upgrade, and I will be replacing the sand.

Still, has anybody encountered this level of inconsistency? From 0.05 to 0.5 within a couple of weeks? And then back to below 0.1 ppm?

Seeing as a system is bacterial driven its not alarming to see levels fluctuate depending on the bacterial processing working within. I do agree with the information and suggestions others have provided, but additionally the constant inconsistency and fluctuations you report makes me wonder if you have a nutrient imbalance which is making reducing your p levels a real challenge. What is your no3 at? I'm curious to know if you are nitrate limited? Your system could just be extremely efficient at processing no3 as It was a pre established system, being lightly stocked, and some of the means you are employing to control nutrient levels. This could also line up with the fluctuations you are seeing and a heavy feeding a few days before you test or slack on cleanings could actually result in decreased levels of po4. Whereas in an attempt to keep po4 low you reduce and limit feeding or do an aggressive cleaning etc. on a given day which could result in an increased level of po4. No3 must be present to reduce po4, bacterial speaking. Limited N to process, limited P being processed. No extra N to process, no more P being processed. But If you do have elevated nitrate levels then the above should not be an issue and you should continue to aggressively go after p just as you are and if you follow the advice others have given you will slowly get levels where you want them. If you are nitrate limited then you may have to make additional changes elsewhere along with what was suggested by others.