battling PO4

[MarkSzy]

looking for some advice, I have been fighting my PO4 levels for a long time now. I have tried not feeding certain types of foods and that hasn't seemed to make a difference. I use an auto feeder to feed freeze dried foods at small amounts throughout the day and one large feeding with frozen foods, pellets and 1 sheet or nori.

I have finally decided to post because i am stumped, the other day i finally tested my RODI water even though it is ready 0 TDS and found .07 levels of PO4 using a hanna tester. I thought this was from the amazon bought cheap old DI resin i bought. So i went and got some name brand resin and now my PO4 out of the RODI tested at .4, not .04. i would have thought my PO4 would be 0 after the DI change, o and my RO membrane is less then a year old. i also changed today my sediment filters just incase.

ALK: 8
CA:410
mag:1470
Nitrate: 0
PO4: .37

I dont want to keep using GFO if i can help it, so if anyone has an idea of what part of my RODI i should attach next would be great. thanks

 

[Errol]

I had the same problem. Used Phosphate-E from Brightwell (5-10mL into skimmer section of my sump if levels go up). Very powerful, no adverse effects that I can see.

 

[MarkSzy]

Sorry, I’m using a 5 stage RODI.

 

[MarkSzy]

I had the same problem. Used Phosphate-E from Brightwell (5-10mL into skimmer section of my sump if levels go up). Very powerful, no adverse effects that I can see.

I have used this as well and it does work great. My problem is I have 0 nitrates so I have removed my filter pad. The filter pad is the only way to catch the bonded PO4 to the brightwells.

 

[Mixed Reefer]

I would have someone local test your phosphate. Just to double check. Phosphates gets absorbed by your rock so will take time to remove. Use gfo till you get it lower and keep watching your input.

 

[MarkSzy]

another note is my tank is 5 years old, I'm trying to narrow down the source instead of fighting it forever.

 

[Mixed Reefer]

another note is my tank is 5 years old, I'm trying to narrow down the source instead of fighting it forever.

Another thought is dried foods are higher in phosphate

 

[cablez]

Got a refugium??? That should eat phosphates up.

 

[MarkSzy]

Got a refugium??? That should eat phosphates up.

I do have a refuge, i have grape caulerpa in it that grows like crazy.

 

[MarkSzy]

Another thought is dried foods are higher in phosphate

i have tried cutting out the pellets for a month and then the freeze dried for a different month but neither seemed to make a dent.

 

[shrimpchips]

keep dosing the Phosphate E, dose nitrate, use GFO once PO4 is stabilized. I have the same phosphate issue due to years of relying heavily on pellet feeders for feeding multiple times a day. Super low nitrates unless dosed and high phosphates. I drop pool phosphate remover (lanthanum chloride, same stuff as Phosphate E) into my filter roller to pull phosphates and it works pretty well.

 

[afboundguy]

I added small amount of GFO with the phyto I dose and have had great success lowering my phosphate from 0.37 back in Dec 2024 to 0.06 as of a few days ago.
Dosing phyto helps lower nitrates and phosphate by consuming them in your tank.

 

[Swordsman82]

It not as popular any more, but I carbon dose with Tropic Marins NP Bacto Balance. It keeps my PO4 low but not zeroing out.

 

[MarkSzy]

keep dosing the Phosphate E, dose nitrate, use GFO once PO4 is stabilized. I have the same phosphate issue due to years of relying heavily on pellet feeders for feeding multiple times a day. Super low nitrates unless dosed and high phosphates. I drop pool phosphate remover (lanthanum chloride, same stuff as Phosphate E) into my filter roller to pull phosphates and it works pretty well.

What do your nitrates look like? Mine use to be high so I didn’t have a problem using phosphate e and a filter pad.

 

[MarkSzy]

I added small amount of GFO with the phyto I dose and have had great success lowering my phosphate from 0.37 back in Dec 2024 to 0.06 as of a few days ago.
Dosing phyto helps lower nitrates and phosphate by consuming them in your tank.

I have been dosing phyto a bit because I recently added a frag tank to the system which added 45 gallons of water volume.

Just know I was having this issue before adding the frag system.

 

[MarkSzy]

It not as popular any more, but I carbon dose with Tropic Marins NP Bacto Balance. It keeps my PO4 low but not zeroing out.

I did read about this method but I’m not sure it’s for me.

 

[MarkSzy]

Thanks for all the input but I still don’t know how my PO4 out of my RODI can go from .07 to .40 after filter changes?

 

[dz6t]

Thanks for all the input but I still don’t know how my PO4 out of my RODI can go from .07 to .40 after filter changes?

Bad batch of DI resins.
Or, if you are using Hanna checker, the new DI resins leach colored compounds in the water that interfere with the reading from the checker.
Either way, bad resins.

 

[shrimpchips]

What do your nitrates look like? Mine use to be high so I didn’t have a problem using phosphate e and a filter pad.

At one point my PO4 had crept up to 0.97 and NO3 was 0.3 both by Hanna checker. I’ve brought my NO3 up to 15 and PO4 is 0.37 now and falling without adding LaCl (mainly due to lack of time to drip LaCl the past few weeks.

 

[MarkSzy]

Bad batch of DI resins.
Or, if you are using Hanna checker, the new DI resins leach colored compounds in the water that interfere with the reading from the checker.
Either way, bad resins.

Dong, so you think both batches of DI resin could be bad?

I’m hoping it’s the leaching you mentioned.