Phosphate rising through the roof!

[sanzz18]

So I don’t know what the heck is going in with my phosphate in my tank. It has increased from under 0.1 at the end of June, to 0.5 as of tonight. This is using a Hannah checker.

Tank is about 9 months old. Had to dose phosphates almost 4-5 months ago while battling dinos cause it was 0. Havent dose ANY supplement or anything since. I have a decent bioload so I feed 1 1/2 cubes of mysis, a 1” chunk of rods frozen, and a sheet of omega green nori every single day. I have no lost any fish in the tank for months.

I just tested my RODI water and got a 0.04 after noticing my TDS showing 1. Can this reading cause this ginormous spike?

Please help me, I have no idea where to start.

 

[SPR1968]

I use rowaphos in both my systems to keep phosphate locked down very low at less than 0.03 but you will need to change it frequently to start or it won’t work

Also use it in a reactor

 

[Randy Holmes-Farley Verified Community Expert]

High phosphate is not the end of the world and some great tanks have 1 ppm phosphate, but if you want it lower, many/most tanks need to actively export it.

 

[sanzz18]

I definitely want it lower cause I can notice I am cleaning my glass more, the stylopora sps tester I got looks like it is losing polyps so I have to assume it is from the high phosphates.

What would cause this huge spike in such a short time though? Is it my rodi water?

 

[Randy Holmes-Farley Verified Community Expert]

I definitely want it lower cause I can notice I am cleaning my glass more, the stylopora sps tester I got looks like it is losing polyps so I have to assume it is from the high phosphates.

What would cause this huge spike in such a short time though? Is it my rodi water?

Only way to know about the source water is to test it, but foods are usually by far the biggest source unless you use raw tap water.

 

[sanzz18]

Only way to know about the source water is to test it, but foods are usually by far the biggest source unless you use raw tap water.

I had to check my post to make sure I put it. When I tested my water it was 0.04ppm.

 

[Randy Holmes-Farley Verified Community Expert]

I had to check my post to make sure I put it. When I tested my water it was 0.04ppm.

Then that is not the main source. Foods add tens to hundreds of times as much each day.

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.

reefs.com

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the “crappy” RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let’s assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.

 

[sanzz18]

Then that is not the main source. Foods add tens to hundreds of times as much each day.

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.

reefs.com

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the “crappy” RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let’s assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.

So this is normal then what my phosphate is doing?

So if I do not want to decrease the amount I feed my tank, the only way is exporting phosphate right? Would you say my first step should be gfo?

 

[Randy Holmes-Farley Verified Community Expert]

So this is normal then what my phosphate is doing?

So if I do not want to decrease the amount I feed my tank, the only way is exporting phosphate right? Would you say my first step should be gfo?

Yes. I'd use GFO or growing macroalgae (or both), but some folks like lanthanum dosing.

 

[sanzz18]

Yes. I'd use GFO or growing macroalgae (or both), but some folks like lanthanum dosing.

Last question. I have never used gfo before. I heard you are supposed to drop it slow so you don't shock corals. Is this true and how much of the recommended amount should I use. Thanks for your help.

 

[Randy Holmes-Farley Verified Community Expert]

Last question. I have never used gfo before. I heard you are supposed to drop it slow so you don't shock corals. Is this true and how much of the recommended amount should I use. Thanks for your help.

Yes, gowing slow is good, and with GFO I expect it will be slow to lower if you use reasonable amounts.

 

[jda]

Take a few minutes and understand how phosphate binds to aragonite (rock and sand) and also GFO. The aragonite and GFO will bind to "equilibrium" with the water level amount... if the water level amount goes up, the stuff will bind a bit more, if it goes down, it will release some. When you go to remove this, the rock and sand will release some when you put the GFO in the tank. What you DO NOT want is to use a lot of GFO, lower the water level amount a bunch and then have it bounce back up quickly when the aragonite unbinds. You want to use very small amounts of GFO changed very often so that the downward trend line is more linear instead of a roller coaster. Both the aragonite and GFO can unbind as fast as it binds, which can be in hours to a day.

A tip - always change your GFO if you are going to change water since it will unbind when you are done.

If you started with dry/dead rock, the rise could be dead organics decaying and exposing new aragonite deeper into the rock that is now unbinding into the water. The rock and sand can act as a large reservoir of phosphate will can take a long time and much GFO to remove. It takes patience and time.

 

[Funston07]

I carbon dose to keep my phosphates and nitrates in check. Been doing it for a year with no problems. I know people always say fix the cause but I feel like if you can control it then it's just as effective achieving the same wanted results

 

[sanzz18]

Take a few minutes and understand how phosphate binds to aragonite (rock and sand) and also GFO. The aragonite and GFO will bind to "equilibrium" with the water level amount... if the water level amount goes up, the stuff will bind a bit more, if it goes down, it will release some. When you go to remove this, the rock and sand will release some when you put the GFO in the tank. What you DO NOT want is to use a lot of GFO, lower the water level amount a bunch and then have it bounce back up quickly when the aragonite unbinds. You want to use very small amounts of GFO changed very often so that the downward trend line is more linear instead of a roller coaster. Both the aragonite and GFO can unbind as fast as it binds, which can be in hours to a day.

A tip - always change your GFO if you are going to change water since it will unbind when you are done.

If you started with dry/dead rock, the rise could be dead organics decaying and exposing new aragonite deeper into the rock that is now unbinding into the water. The rock and sand can act as a large reservoir of phosphate will can take a long time and much GFO to remove. It takes patience and time.

Thanks for this great explanation! So for a 180g tank, what is an appropriate amount of GFO to start off with so I keep it linear?

Also, could this big of a spike be a late effect from the phosphate I had to dose 4 months ago to combat dinos?

I carbon dose to keep my phosphates and nitrates in check. Been doing it for a year with no problems. I know people always say fix the cause but I feel like if you can control it then it's just as effective achieving the same wanted results

Yeah. If overfeeding is my cause, then I do not want it fixed, I will just manage it. I want to keep my tangs and other fish all fat/healthy.

 

[sanzz18]

Just as an update, I held off on using GFO as I was waiting for it to be delivered. My phosphate came all the way down to 0.1 from 0.5. Which made me not even use the GFO when it came in. Then, a week later (9/12) it was 0.17. Why does it keep bouncing around? Should I just run a small amount of GFO at this point?

 

[sanzz18]

Bump

 

[ocncheffy]

Sounds like a test kit issue possibly. I had a recent phosphate bottom out event due to my Hannah phosphorus checker showing .2ppm which caused me to add GFO, and kill a lot of my SPS colonies. When testing with another checker and kit from a LFS, my phosphates were only at .04ppm when my hannah reported .2. Thus, adding GFO crashed my phosphates and bleached some SPS.

Get a different test kit such as the NYOS phosphate kit and verify. Or take some sample water to the LFS. I've stopped GFO and my tank is already recovering.

 

[ReefGeezer]

Make sure the test vials for your Hanna kit are are not dirty, hazy, scratched, or etched. That will give you false elevated readings. Buy some new vials from BRS if you have doubts.