Curing rock
- Thread starter EHaddad
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MnFish1
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Curious - how much rock (pounds) vs how much water are you using in your brute trash can? If the amount of rock is high - relative to the amount of water - you might be getting a false high reading (or at least a reading that you needn't worry about)
If its dry rock what is the point of 'curing it' either way? I wasn't aware that measuring phosphate was a factor in curing dry rock. I have never done it - I just put it into the tank.
If its dry rock what is the point of 'curing it' either way? I wasn't aware that measuring phosphate was a factor in curing dry rock. I have never done it - I just put it into the tank.
OP
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EHaddad
Active Member
It is a large amount of rocks probably near 150lbs. In a 55 gallon brute. I have some Aquamaxx rock and some dry Tonga. I was trying to decide if I needed to cure it or not but I did it just to be safe. So I am currently getting phosphate being leeched from the rock.
MnFish1
10K Club member
If it were me (and I'm sure there are multiple opinions on this) - I wouldn't worry about the Phosphate. Thats a lot of rock in a small amount of water. From what I've read - it should be ok as is (and it will save you time and multiple water changes).
OP
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EHaddad
Active Member
So the rock is still curing I did three 20 gallon water changes since my last post and added a decent amount of different Types of phosphate removers and the levels haven’t dropped any. Am I doing something wrong or do I need to just keep at it? All of my rock was dry live rock and a lot of people told me I didn’t need to cure it at all so it’s making me think I’m doing something wrong. I thought maybe it was something in my water so I tested newly mixed salt water and it did not register anything at all.
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EHaddad
Active Member
Did another 20 gallon water change today and the Phosphates haven’t gone down any. Also I have had phosphate remover in there the last three weeks and changed it out three times. #help
JOKER
2500 Club Member
Have you tried running a reactor with GFO? That's also another good remedy. I went with phosphate remover, and GFO after using muriatic acid on my rocks that were dry pukani. The thing with dry rocks, they are just live rock that has been dried out so all the dead organisms and stuff in them is still present. The nearest to 0 you get PO4 the happier you will be with the tank after it is running.
Dkeller_nc
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You asked if you were doing something wrong. The short and blunt answer is "yes", and that's testing with the Red Sea test, or any other test that you judge by eye against a color chart. The difficulty is that the fundamental chemistry of the test just doesn't yield a strong enough color in the ranges that we're interested in to be all that useful.
So your first action should be to get a Hanna Checker ULR Phosphate test. Buy the 25 test refill when you do - it only comes with enough reagent for 7 tests. It will help you out greatly when you're trying to decide if you've gotten all of the phosphate out of the rocks, and you will absolutely need it when you set up the reef tank, so it won't be a boat anchor after your rock curing is done.
The second aspect of this is that assuming that the Hanna Checker verifies what you seeing and there really is residual phosphate, you're trying to re-dissolve calcium phosphate on the surface of the rocks. That's assuming that you didn't have a lot of organic residue on the rocks like leftover sponges, clams, etc... that are now rotting and releasing phosphate. Presuming that's not the case and all of it is abiotically-precipitated calcium phosphate, you've a couple of choices. The first is what you've been doing, which is precipitating or absorbing the phosphate in the water, or removing it with water changes to drive more of what's in solid form on the rocks to redissolve. This by its very nature is a slow process. If you want to continue doing this, the fastest way to do it is to maintain tank temperature (add a heater if you don't have one in there already), keep the water circulating (add a pump), and be absolutely sure that you keep the phosphate concentration in the water at zero. As others have mentioned, the best way to do this is with lanthanum chloride. The lanthanum phosphate that's formed when you add lanthanum chloride to the water is for all practical purposes completely insoluble, so it removes any dissolved phosphate from the water column. However, realize that you must remove the precipitate in some manner - most filter it out with some sort of mechanical filter. If there's a lot of this precipitate in the water that you use for the phosphate test, it will show as free phosphate, even though it's not.
The potentially long wait for calcium phosphate on the surface of the rock to redissolve is what leads people to do an acid wash of the rock with diluted hydrochloric acid, as it will remove the top surface of the rock and any calcium phosphate that's on that surface in a few minutes. The only drawback to this process is that if the rock was formed in a high phosphate environment, there may actually be calcium phosphate actually in the rock itself, in which case removing the surface simply exposes more phosphate. In general though, it seems that folks are largely successful with the acid wash, so it seems that having phosphate distributed throughout the rock is relatively rare.
