LR leaching Phosphate

[rfurst]

I bleached LR but it was left in the bleach solution for about a week. It now leaches Phosphate. Why?

To test, I filled a 40g tank with the LR and newly made water with 0 phosphate using Hannah meter. I used two BRS media canisters using GFO, but it didn't help. I kept replacing the water but reading always shot up to .7 - 1 after a few days.


I have this LR in a 240g that I'm running as a FOWLER tank and I can get the phosphate to drop appreciably using Brightwell Phosphate-E but it won't stay lower without constant dosing.

I had been using this LR in a tank prior to bleaching ( I was starting up a new tank and wanted everything sterile to start with) without issues.

At this point, I am primarily interested in an explanation of why LR would start leaching Phosphate after being in bleach for prolonged period of time.

 

[penfold2]

Bleach will break down organics, but it does not dissolve phosphate that is chemically bound to rock. To do that you need to keep the rock in low phosphate water. A new equilibrium will be established as the high phosphate rock begins dissolving phosphate into the low phosphate water. But you need to continually remove phosphate from the water to drive that equilibrium. I did it with Phosphat-E and it took a good week of daily additions before the phosphate stopped rising. But it may take several weeks or even months depending on how much phosphate is bound in your rock.

 

[exnisstech]

What is your PO4 level at?

EDIT: I like the method @penfold2 described "snip"

 

[areefer01]

I bleached LR but it was left in the bleach solution for about a week. It now leaches Phosphate. Why?

To test, I filled a 40g tank with the LR and newly made water with 0 phosphate using Hannah meter. I used two BRS media canisters using GFO, but it didn't help. I kept replacing the water but reading always shot up to .7 - 1 after a few days.


I have this LR in a 240g that I'm running as a FOWLER tank and I can get the phosphate to drop appreciably using Brightwell Phosphate-E but it won't stay lower without constant dosing.

I had been using this LR in a tank prior to bleaching ( I was starting up a new tank and wanted everything sterile to start with) without issues.

At this point, I am primarily interested in an explanation of why LR would start leaching Phosphate after being in bleach for prolonged period of time.

You mentioned FOWLR so maybe just keep an eye on it unless you have a massive algae problem. I run my mixed reef with 40 ppm nitrate and 1.1 ppm phosphate without much concern. I've had phosphates as high as 1.9 ppm so your mileage may vary.

If you go the route with phosphate E or similar lanthanum chloride products be aware that some hobbyist have reported issues with tangs. Especially in the Genus of Zebrasoma. Yellow Tangs for example.

 

[rfurst]

Bleach will break down organics, but it does not dissolve phosphate that is chemically bound to rock. To do that you need to keep the rock in low phosphate water. A new equilibrium will be established as the high phosphate rock begins dissolving phosphate into the low phosphate water. But you need to continually remove phosphate from the water to drive that equilibrium. I did it with Phosphat-E and it took a good week of daily additions before the phosphate stopped rising. But it may take several weeks or even months depending on how much phosphate is bound in your rock.

I am curious, though, why the phosphate started leaching after the bleach treatment when it was not leaching before?

 

[VintageReefer]

Is the rock going in a different volume of water?

If you put the rock in water with less phosphate, or zero, it will unbind and release

 

[penfold2]

Bleach will break down organics, but it does not dissolve phosphate that is chemically bound to rock. To do that you need to keep the rock in low phosphate water. A new equilibrium will be established as the high phosphate rock begins dissolving phosphate into the low phosphate water. But you need to continually remove phosphate from the water to drive that equilibrium. I did it with Phosphat-E and it took a good week of daily additions before the phosphate stopped rising. But it may take several weeks or even months depending on how much phosphate is bound in your rock.

I am curious, though, why the phosphate started leaching after the bleach treatment when it was not leaching before?

If the rock is leaching that much phosphate now, I would think that it was in a high phosphate environment for some time. What were your phosphate levels in the old tank?

 

[rfurst]

If the rock is leaching that much phosphate now, I would think that it was in a high phosphate environment for some time. What were your phosphate levels in the old tank?

The longer story is... I had a 240g and 125g tank, both were mixed reef with quite a bit of SPS, and both tied to the same 150g sump. So, probably 400g, or so, in the system. PO4 levels were generally below .1ppm with nitrate in the 20-30 ppm range. Then, I isolated the 240 from the system, took the LR out and bleached it. It sat for a while and then I put it back into the 240 g. After cycling, Nitrate was fine but PO4 was very high. I added fish and have been running as FOWLER ever since since I haven't been able to get PO4 down low enough. The 125g tank and sump with the original rock is fine although I have been running it with only coral and no fish so no reason for those parameters to be high.

So, original system was fine. Split the system in two with the 240G tank being emptied, cleaned, and restarted with the bleached rock. I've bleached LR many times in the past with no issues but this was the first time doing so for an extended period of time. This led me to believe, that something about the prolonged bleach period resulted in the LR now leaching PO4.

 

[Miami Reef]

Is the rock going in a different volume of water?

If you put the rock in water with less phosphate, or zero, it will unbind and release

Yes. I was thinking the same thing.

 

[BryanM]

Was the test only LR, or was there new substrate in that tank too?

 

[penfold2]

The longer story is... I had a 240g and 125g tank, both were mixed reef with quite a bit of SPS, and both tied to the same 150g sump. So, probably 400g, or so, in the system. PO4 levels were generally below .1ppm with nitrate in the 20-30 ppm range. Then, I isolated the 240 from the system, took the LR out and bleached it. It sat for a while and then I put it back into the 240 g. After cycling, Nitrate was fine but PO4 was very high. I added fish and have been running as FOWLER ever since since I haven't been able to get PO4 down low enough. The 125g tank and sump with the original rock is fine although I have been running it with only coral and no fish so no reason for those parameters to be high.

So, original system was fine. Split the system in two with the 240G tank being emptied, cleaned, and restarted with the bleached rock. I've bleached LR many times in the past with no issues but this was the first time doing so for an extended period of time. This led me to believe, that something about the prolonged bleach period resulted in the LR now leaching PO4.

I don't know of any reason why bleach (even prolonged) would cause rock to release phosphate at a higher concentration than it was previously exposed to. Is it possible that something other than straight bleach was used, like TSP?

 

[Randy Holmes-Farley Verified Community Expert]

I am curious, though, why the phosphate started leaching after the bleach treatment when it was not leaching before?

Why do you assume none came off into the bleach?

 

[Randy Holmes-Farley Verified Community Expert]

Extensive bleaching of organic matter will produce phosphate (and likely nitrate) by decomposing the rest of the organic and leaving behind the N and P.

 

[KrisReef]

Why do you assume none came off into the bleach?

I don’t think this is the right question (if I read the op’s question correctly?)

The guess I am thinking is that the op measured higher levels of P after bleaching, while expecting the levels would be lower.

Your comment about the dissolving of organics from the rocks in bleach, leaves me wondering if the freed P from the organics attached to the rocks and increased the amount that was left behind after bleaching, resulting in higher levels to dissolve into water after the bleach treatment?

I was thinking about this and hoping that you or someone would know if this is possible or likely?

 

[rfurst]

Why do you assume none came off into the bleach?

Randy, Yes, some PO4 could have come off during bleaching. I was thinking more in terms of what was happening in my tank. Is there anything about prolonged exposure to bleach that would initiate or accelerate the PO4 leaching?

 

[Randy Holmes-Farley Verified Community Expert]

Randy, Yes, some PO4 could have come off during bleaching. I was thinking more in terms of what was happening in my tank. Is there anything about prolonged exposure to bleach that would initiate or accelerate the PO4 leaching?

It may literally add phosphate, for the reason I suggested above. :)