Phosphates non existent...

[Japtastic]

My tank is 340 gallons and around 5 months old, FOWLR.

I did have Chaeto that grew very well for the first few months and then slowly died off.

Although I've been keeping tropical fish for the last 30 years, this is my first step into marine. It's been a steep learning curve!

I believe the reason my Chaeto died off was a combination of no iron and no phosphates.

Nitrates are 80ppm and the light is a Kessil H380.

Over the last 2 weeks, I have dosed Iron to 0.15ppm and tried to keep Phosphates at 0.06 by dosing it through the DIY recipe on here.

Problem is, every time I dose 0.06, this is non-existent 24 hours later. Red Sead Test Kit confirms I get to 0.06 after dosing and 0 24 hours later.

There is virtually no Chaeto left so it's not that, that's taking it up. Is the live rock absorbing it all?

I've recently learnt a hard lesson and the tank had to be fallow for 76 days. I did ghost feed/ammonia dose during that time.

For that reason, I don't want to get another ball of Chaeto without QT which is going to take too long to take care of the Nitrates.

I decided that going forward I would do some carbon dosing and then get the Chaeto going once everything settles.

I've been dosing Vinegar from @Randy Holmes-Farley guide for the last week. I'm aware that this is going to take some time but with non-existent Phosphates is this going to be a non-starter as well?

Need some advice chaps. Thanks.

 

[Scrubber_steve]

I use the salifert PO4 test kit & it appears to read zero. But when the test solution is compared to plain water in a second vial, the test solution then shows some faint blue color rather than clear, so i believe the actual PO4 is around 0.03.
Although the PO4 is never higher than that i have never had trouble growing ulva on my scrubber screen.

 

[Japtastic]

Yes, I did check that and this is the Red Sea kit pro so you compare it with two vials. Just seems to be absolutely 0.00!

 

[Labridaedicted]

Try a low range hanna checker. Mine sits around 4-6 ppb or .004-.006 ppm. I'd wager your not at zero, but just very low. In a low nutrient system, it is not uncommon to burn through small amounts of added po4 very quickly as they are uptaken when available. Some systems just process nutrients well.

Carbon dosing is less dependent on phosphates to remove nitrogen than algae and therefore should work as long as some po4 is available. You'll see that alot of ULNS will run biopellets or carbon dosing due to this.

I'm sure Randy probably has much more info than this, though.

 

[Breadman03]

Carbon dosing is less dependent on phosphates to remove nitrogen than algae and therefore should work as long as some po4 is available.

The idea behind carbon dosing is that life processes require nitrogen, phosphate, and organic carbon to occur. In our tanks, we tent to run out of organic carbon before nitrogen or phosphate, thus adding organic carbon to allow bacteria to flourish and uptake the excess nutrients from the water and be skimmed out of the system. One can drive this process hard enough to strip the system to the point that the organisms we want cannot survive. I mention this not to dissuade you from carbon dosing, but to caution you on the risks. I am dosing vinegar as we speak, err, type.

Here is an article from Randy Holmes-Farley, a well-respected, successful chemist who happens to be a reefer, on the topic that may be helpful to you.

http://reefkeeping.com/joomla/index...ar-dosing-methodology-for-the-marine-aquarium

 

[Japtastic]

Try a low range hanna checker. Mine sits around 4-6 ppb or .004-.006 ppm. I'd wager your not at zero, but just very low. In a low nutrient system, it is not uncommon to burn through small amounts of added po4 very quickly as they are uptaken when available. Some systems just process nutrients well.

Carbon dosing is less dependent on phosphates to remove nitrogen than algae and therefore should work as long as some po4 is available. You'll see that alot of ULNS will run biopellets or carbon dosing due to this.

I'm sure Randy probably has much more info than this, though.

Thanks for that. Yes, it’s on the list of things to buy.

What’s using the Phosphate that I’m putting in then? Absorption or something else?

 

[Japtastic]

The idea behind carbon dosing is that life processes require nitrogen, phosphate, and organic carbon to occur. In our tanks, we tent to run out of organic carbon before nitrogen or phosphate, thus adding organic carbon to allow bacteria to flourish and uptake the excess nutrients from the water and be skimmed out of the system. One can drive this process hard enough to strip the system to the point that the organisms we want cannot survive. I mention this not to dissuade you from carbon dosing, but to caution you on the risks. I am dosing vinegar as we speak, err, type.

Here is an article from Randy Holmes-Farley, a well-respected, successful chemist who happens to be a reefer, on the topic that may be helpful to you.

http://reefkeeping.com/joomla/index...ar-dosing-methodology-for-the-marine-aquarium

Thanks, my understanding near enough matched your good summarisation. Will definitely try and find the time to read the whole article though.

How long did it take for your carbon dosing to start to work?

 

[Breadman03]

It usually takes several weeks or more until the effect is notable. Just keep testing regularly and make gradual changes.

 

[wesman42]

Took me a week because I doubled the dose until I went over, then did a water change. It still absorbed it fast, but not nearly as fast.

 

[Japtastic]

Took me a week because I doubled the dose until I went over, then did a water change. It still absorbed it fast, but not nearly as fast.

Took only a week to carbon dosing to start working? Seems very quick compared to others.

Doubled the dose of Vinegar?

 

[wesman42]

Took only a week to carbon dosing to start working? Seems very quick compared to others.

Doubled the dose of Vinegar?

No, I didn't need to carbon dose but I did need to do phosphate. I dosed Seachem Phosphorous.

Carbon dosing does take longer.

 

[User1]

Try a low range hanna checker. Mine sits around 4-6 ppb or .004-.006 ppm. I'd wager your not at zero, but just very low. In a low nutrient system, it is not uncommon to burn through small amounts of added po4 very quickly as they are uptaken when available. Some systems just process nutrients well.

Carbon dosing is less dependent on phosphates to remove nitrogen than algae and therefore should work as long as some po4 is available. You'll see that alot of ULNS will run biopellets or carbon dosing due to this.

I'm sure Randy probably has much more info than this, though.

I was going to say something similar. I actually use the Hanna checker but the 713 model and not the one you suggest. The low range is probably the better of the two to use for this very reason. In fact I have a tank that is recently cycled (March 28th 2018) with 150 lbs of Pukani. We all know this has a history of leaching phosphates, right? In any case last night I ran a series of tests back to back using the 713 and each time it read 0.0. I even ran another set of tests using a spare vile filled with tank water to run through quicker the first part of the test and reused earlier water samples pre-mixed. Same results. Test after test 0.0. My understanding is that the 713 is + or - .04 so guessing I'm at least +.04...

Get the lower range / measurement of the two. It is a better product in the long run.

 

[Japtastic]

Thanks, yes seems sensible.

Would still like to know where all the Phosphate has gone that I have dosed. Live rock?

 

[Breadman03]

If your system was limited by phosphate, it could have taken up a bunch of it quickly. Think about it like a bunch of construction workers waiting on nails. At some point, they are all sitting there with their hammers and will grab a bunch of nails at once when they come in instead of a few at a time.

 

[Japtastic]

Got you but just wondering what could be wanting the Phosphate in my system now that the Chaeto is gone... Don't want to be continually dosing Phosphate and it all going into the live rock..

 

[bubbaque]

Try a low range hanna checker. Mine sits around 4-6 ppb or .004-.006 ppm. I'd wager your not at zero, but just very low. In a low nutrient system, it is not uncommon to burn through small amounts of added po4 very quickly as they are uptaken when available. Some systems just process nutrients well.

Carbon dosing is less dependent on phosphates to remove nitrogen than algae and therefore should work as long as some po4 is available. You'll see that alot of ULNS will run biopellets or carbon dosing due to this.

I'm sure Randy probably has much more info than this, though.

Just a little tip. If you are getting 4-6 ppb on the hanna it doesn't convert to .004 - .006. It converts to .012 - .018.

 

[Randy Holmes-Farley Verified Community Expert]

Got you but just wondering what could be wanting the Phosphate in my system now that the Chaeto is gone... Don't want to be continually dosing Phosphate and it all going into the live rock..

Well, the calcium carbonate surfaces will take it up whether you want them to or not. It's not something to be feared or avoided, and you can't anyway.

 

[Randy Holmes-Farley Verified Community Expert]

If your system was limited by phosphate, it could have taken up a bunch of it quickly. Think about it like a bunch of construction workers waiting on nails. At some point, they are all sitting there with their hammers and will grab a bunch of nails at once when they come in instead of a few at a time.

lol

That's an analogy I've never heard before.

 

[Japtastic]

Thanks, I need to read more of your articles!

 

[Lasse]

I´m not afraid of buffering phosphates in live rocks (or any other places) It will serve as a buffer if you are going too low in PO4 concentration in the water column, hence supply your corals with P if PO4 becomes 0 in the water column.

Sincerely Lasse