Phosphate Checker = Junk?

[mtrcyclefish]

So let me start with a bit of background. A few years ago my tank was extremely successful. I had very good coral growth and color. Then I went on vacation and returned to a pump that had leaked, a top off system that had gone crazy, and a tank that looked, and smelled, like thick clam chowder. Needless to say it was a complete loss. I cleaned the rocks and restarted the system from scratch using the same rocks and sand. Since then no corals will grow or thrive in my tank. Everything will survive, but no growth, no color, no PE. Algae grows very well. The tank was moved almost 2 years ago and during that I replaced the sand and acid washed all of the rock. For about 3 months things were improved. Still very little growth and brown corals, but at least the algae issue seemed to subside. All during this time I was testing phosphate with a Hannah Phosphate checker and ALWAYS got a 0 reading. I even bought a calibration set for the Checker thinking that it was not working and it was spot on.

As a bit of an experiment I bought some Lanthanum Chloride because I suspected that the tank had high phosphate. I put about 1 ml of LC into a liter of water and dripped a few drops into the tank. It looked like I had dripped a quart of milk into the tank.

So here are my questions. Is it possible that my rocks became completely saturated with phosphate when my tank crashed and turned into clam chowder and have been leaching it back into my system for all these years? I know the Checker only tests for a certain type of phosphate so has it been missing this issue all along? I run GFO but could my system be so overwhelmed with phosphate that the GFO doesn't stand a chance? Will dripping the LC slowly over a couple of weeks help resolve the phosphate saturation issues?

I should mention that I currently only have 4 fish and I feed very lightly. The tank is 115 gallons with about 60 in the sump. All other params are where they need to be.

 

[madjoe]

Mine always reads zero to lol and im over stocked and havent done a w/c in 3 months oh and run a super skimmer so id say those test t pos

 

[jrpark22000]

The checker I had wasn't junk, but I was never happy with the results. While it did read zero too often, more often it did show values. My problem with it was it was never consistant test to test, or reagent lot to reagent lot.

It could be possile the test reads low as the growth in the tank is using the free po4 being leached from the rocks keeping the free po4 in the water low.

 

[Volcano1]

LC is the only cost effective way I've found to lower high levels of phosphate.I do drip mine through a 5 micron sock, with a slow feed and drip rate 2-3 seconds. With a high level it will clog the sock pretty quickly. I went through around 6-7 in a day or so, dripping 2-3 liters of water, with 5ml per liter. It did take a while, the rock will leach for a few weeks.It seemed to take a very low level of phosphate in the tank water to pull it out of the rock. Keep an eye on your alk, LC my cause it to drop. If you bring levels down to quick it can stress some corals. There have been some reports that some fish my be sensitive to LC. I always did mine through a sock and had no fish issues.
I went through this last year ,after a crash, and that is how i attacked it. HTH's.

 

[mtrcyclefish]

Where did you get the 5 micron sock?

 

[Volcano1]

Supplier near the city, I'll see if I can find them, they had the smallest quantities to order, Zorro ?

 

[Volcano1]

http://www.zoro.com/value-brand-filter-bag-felt-poly-90-gpm-5m-pk5-1eux8/i/G1000352/

Think these are the ones.
I used a ro canister filter wrench for the sock holder, they do get heavy full of water,you may find smaller ones if need be.

 

[Volcano1]

http://www.thecarystore.com/containers-catalog/industrial-filtration-liquid-filter-bags-size-1-polyester-felt-filter-bags/pe5p1p-filter-bag-21WCAL

Another place mentioned on RC, never used them though.

 

[Volcano1]

http://www.thecarystore.com/containers-catalog/industrial-filtration-liquid-filter-bags-size-1-polyester-felt-filter-bags/pe5p1p-filter-bag-21WCAL

Another place mentioned on RC, never used them though.

 

[mtrcyclefish]

Thanks for the links. I have read about some people having success with dripping the LC directly into their skimmer. Have you ever tried that method?

 

[Volcano1]

No, but you will get a white film on anything the where you have LC and tank water with phosphate meeting.It's a little sticky to remove.

 

[Volcano1]

There is a huge thread on RC about LC, pack a lunch if you want to read the whole thing.

 

[EricTheRed]

I would have thought that acid washing the rocks and removing the surface layer would have removed any absorbed phosphates from your crash. However, perhaps the acid wash exposed the interior of rock that was naturally high in phosphate. Some rock is known to hold phosphate so maybe by burning off the top layer you exposed a fresh layer and it leached...? But even if that did happen it shouldn't still be leaching years later.