Does this test prove that my rocks are leaching phosphate?

[QuinnLee512]

I took this Caribsea Liferock dry rock from my tank and put it in this bucket of rodi water. The rodi water had .03 phosphates. I let the rock sit in the bucket for 2 days. The water had .07 phosphates after 2 days. I checked using a Hanna checker.

 

[ilyad]

It looks like there's plenty of life on your rocks... which needs saltwater to live. If you took it out and put it in RODI water, you would have killed a lot of it, which would cause a spike in Phosphates. If you want to test if your rocks are leeching, you'd have to keep the tested water at temp and salinity level that would not cause die off.

 

[EeyoreIsMySpiritAnimal]

I don't believe saltwater test kits will accurately detect phosphates in RODI water, but could be mistaken.

 

[QuinnLee512]

Oh darn. I guess I should have used saltwater.

 

[Randy Holmes-Farley Verified Community Expert]

Assuming that’s all the rise you get from seawater, it’s not much.

 

[QuinnLee512]

Right. I was wondering if maybe in my display tank where there's a lot more rock if it's leaching a lot more. Also someone had said that dry rock does not leach so I wanted to prove/disprove that statement.

 

[QuinnLee512]

I've been living phosphate hell for the past 3 months. Just took a reading and it's .28. Nitrate at 9. I am not overfeeding. I actually haven't fed in 4 days to see if food is the source. Rocks and sand is the only thing that I can think of.

 

[Randy Holmes-Farley Verified Community Expert]

Right. I was wondering if maybe in my display tank where there's a lot more rock if it's leaching a lot more. Also someone had said that dry rock does not leach so I wanted to prove/disprove that statement.

Assuming it had reached equilibrium with the new water, putting in all of the rock to the same water would not have raised it much more.

Rock with phosphate does not add a fixed amount, it raises the concentration to a fixed equilibrium concentration.

 

[DE FISH]

This is dry rock not Live rock the name is misleading

 

[Miami Reef]

I've been living phosphate hell for the past 3 months. Just took a reading and it's .28. Nitrate at 9. I am not overfeeding. I actually haven't fed in 4 days to see if food is the source. Rocks and sand is the only thing that I can think of.

Just use GFO. It works incredibly well for phosphates.

I would never stop feeding.

New tanks usually have high phosphates from the dry rocks/sand. Once you remove the phosphates, almost all future phosphates will come from food. But it won’t raise it by the amount you’re seeing in such a short time.

 

[QuinnLee512]

I have used just about everything. Gfo, rowaphos, lanthanum, nopox, elimi phos, np pro. I just bought an algae reactor to try next

 

[Miami Reef]

I have used just about everything. Gfo, rowaphos, lanthanum, nopox, elimi phos, np pro. I just bought an algae reactor to try next

How did you use the GFO? Reactor or in a media bag in the sump?

 

[QuinnLee512]

Brs deluxe reactor. I can get phosphate to come down to around.07 but it'll shoot back up to over .2 the next day before feeding time. That's why I'm guessing all this phosphate is coming from my rocks. I've lost corals and nems.

 

[Miami Reef]

Brs deluxe reactor. I can get phosphate to come down to around.07 but it'll shoot back up to over .2 the next day before feeding time. That's why I'm guessing all this phosphate is coming from my rocks. I've lost corals and nems.

That’s normal. The rocks definitely are bound with phosphates. Use half as much and change the GFO more often (when the water on the output starts climbing). That will work.