Bleach vs Acid

Adding the rock back should be safe enough, as long as it's rinsed well and treated with a dechlorinator. It won't have any filtration capacity for a while, so I wouldn't use the treated rock to replace live rock, though.
 
omreardon - let us know how the process goes for you.

I'm going through the process again as I still have my algae problem. I'm also now thinking my shallow sand bed of argonite sand may be filled if phosphate.

bertoni, others - I'd like to use the same process on my live sand. but I'm afraid that the acid may actually dissolve my sand down to nothing? should I do a shorter, more diluted acid wash?
 
I don't think it's practical to treat sand. I don't know how to make sure that all the surfaces get adequately treated. It might be possible, though.
 
Hmmmm. yea, i agree. id hate to go through the process to find out it didnt work. ok. well, in other news i did just order a Hanna Low Phosphate checker to monitor phosphate as I go through each step.

Right now I have a layer of Cyano growing in my tank. I removed the rock again to see if there was a difference. It did seem like it improved after removing all live rock. So next step is to remove the live sand to a temp holding tank. Measure P04 before and after. Eventually I'll pinpoint the root. I do think its always been my live rock tho and now the sand is just overfilled with P04. And eventually I will clean the rock again, this time taking the time to leave it in fresh RODI and measure an leakage of P04.

Stay tuned...
 
Round 3...

Round 3...

An update to my above post, I'm just finishing my 3rd attempt at battling algae. These last two times its been cyano. Here's what I've done over the past few weeks:

- Removed all the live rock
- Remove all the live sand
- took a refugium with live sand offline
- took a DSB offline

So now I'm running just a bare tank and sump. In the meantime I've put the live rock through the same cycle:

- soaked in approx 3:1 bleach solution to kill off all organisms, dead or alive
- rinsed
- soaked all rock in RODI water with approx 10:1 solution of muriatic acid in attempt to burn off any layers of phosphate (again, all of these numbers are arbitrary and not positive of the perfect ratio)
- rinsed the rock in RODI water

So now I have all of the rock sitting in a clean tub with fresh RODI water and a power head.

GOAL: to determine if the rock is harboring any phosphate, will wait and see if any leeches out of the rock into the fresh RODI. I purchased a Hanna Phosphate checker which should do the trick.

How does this sound? I'm hoping (praying) that IF there is any Phosphate present it will 'show' itself eventually with this process. IF there is no evidence of Phosphate in the water I will have to go with the assumption the rock is 100% FREE of phosphate and....put it back into my tank (will seed it with the live sand in the fuge I took offline).

Hope that gives some good details. Will post pics and results soon.

Any comments welcome!
 
Update

Update

Let me first thanks all of the people who have contributed on this thread again. Never have I learned so much from beginning to end about a single topic I was clueless about before. I have a long update below and really need some guidance on how to move forward next. Now, for the big breakthrough...

As noted above, my most recent batch of clean rock has been sitting in pure RODI water for a few days now. Prior to putting the rock into the tub of RODI I tested the water and the P04 came back as 0.00 (hanna checker). Then, after two days I tested it again (fully expecting to get a reading of 0.00 and continue the mystery). But, to my delight (or dismay :rolleyes:) I was astonished to get a P04 reading of 0.13...meaning there IS still Phosphate in my rock, leeching out into the RODI over the last two days. Wow. Even though I have a long road ahead (below) I am thrilled to finally have an answer. All this time, through several staged of of rock "cooking" and then two separate cycles of Bleach and Acid over the past year or so only to once again battle nutrient issues in my tank, I finally learned that all this time there was most likely STILL P04 in my rock. Honestly, if it came back clean after sitting there for a few days I would be disappointed and still not sure why I've had so many problems over the years.

Next, what to do with the rock?

I've already decided for a couple of reasons to keep it. My tank is large (220g) and I can't afford to stock it with new rock. Also, I dont think there's anyway to sell this rock to anyone else in good conscious and for a good price. So right now I'm keeping it. So.....

What to do with it?

SO far I see a few options and I'd REALLY like some feedback to help me decide the next step. Here's the different approaches I've come up with:

1) Let the rock sit in clean RODI until all po4 leeches out. Means continuous water changes until i get a reading of 0.00. Problem is that I don't know how long that would take. Could be a month. Could be a year. Could be never? And I'm assuming I need to do water changes b/c the p04 and RODI must come to some sort of equilibrium.

2) Let the rock sit and hook up the tub to my GFO reactor to physically pull the p04 out of the water. Just thought of this one today :-) . Again, not sure how long it would take but would mean less water changes (about 35 gallons per change). Also has the potential of using alot of GFO.

3) Finally, just continuing the Acid Bath cycle. I dont mind buying the Muriatic Acid b/c its not expensive. but its a big deal to make the RODI, bathe the rocks in acid, drain the tub, rinse, repeat until I get a 0.00 reading. while this is the most effort I think it would be the quickest.

3b) One other problem with the above is I dont know which rocks really have the p04 in them. So I keep bathing the entire batch. So maybe I make up a series of smaller containers and do the rocks in batches, maybe to isolate the problem better.

And of course I could go back to the other option of just ditching the rock if its too far gone. Would hate to do that.

Anyway sorry for the long update. Very excited and feel like I'm close to solving this problem I've been dealing with for years.

Hoping to get some good feedback and advice to what has become such an informative thread!
 
I would run a gfo reactor until I got a consistent reading of 0.00, then take reactor off line and let rock circulate in ro/di water for several days then test for PO4 again. If still 0.00 rock is good to go, if you get a higher reading run some more gfo.
 
Also, something I found that confuses me a bit...

So, since I put the rock into the fresh RODI I've measured the p04 starting from day two. Here's what I've found:

Day 1 - rock sits in RODI
Day 2 - measured P04 at 0.13
Day 3 - measured P04 at 0.08
Day 4 - measured P04 at... 0.00

Yes, I said it exactly like Dean Wormer there. I was a little confused why it went down on day 3. But baffled at why it read 0.00 last night?

So, maybe, after equilibrium has been reached, its leeching back INTO the rock??
 
Something, like bacteria, might be consuming the phosphate from the water. I'm not sure what's happening, but I wouldn't worry about it.
 
Something, like bacteria, might be consuming the phosphate from the water. I'm not sure what's happening, but I wouldn't worry about it.

Ok thanks. Very strange. Last night I measured and it was back to the exact original measurement from Day Two: 0.13. So it seems like its fluctuating back and forth.
 
So, still trying to decide the next step with this rock, since I decided to keep it:

1) Let the rock sit in clean RODI until all po4 leeches out. Means continuous water changes until i get a reading of 0.00. Problem is that I don't know how long that would take. Could be a month. Could be a year. Could be never? And I'm assuming I need to do water changes b/c the p04 and RODI must come to some sort of equilibrium.

2) Let the rock sit and hook up the tub to my GFO reactor to physically pull the p04 out of the water. Just thought of this one today :-) . Again, not sure how long it would take but would mean less water changes (about 35 gallons per change). Also has the potential of using alot of GFO.

3) Finally, just continuing the Acid Bath cycle. I dont mind buying the Muriatic Acid b/c its not expensive. but its a big deal to make the RODI, bathe the rocks in acid, drain the tub, rinse, repeat until I get a 0.00 reading. while this is the most effort I think it would be the quickest.

I'm leaning towards trying to pull it out with GFO.
 
I'm not sure why the phosphate level would change like that. Any of those approaches would work. It's a personal choice.
 
I was thinking, some sort of imbalance causes the phosphate to leech "out" of the rock, right? Could something cause it to be "absorbed" by the rock? Guess it has to get in there, somehow, to begin with.

1) Pure RODI water with 0.00 P04 causes P04 to leech "out" of the rock and into the water.
2) Then equilibrium is reached
3) Then higher P04 in water causes rock to "absorb" P04?

I'm so not a chemist so just throwing that out there.

I will be hooking my dual GFO reactor up to the rock in the next few days and take approach #2.
 
That scenario can't be quite right. A phosphate higher phosphate level will encourage the rock to adsorb more phosphate, but it'll only go to equilibrium, which should be higher than zero.
 
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