High Phosphate in my mixing station

[Joe Sifuentes]

I have high phosphates in my freshly made saltwater mixing station.
I run a 75 gpd ro system with the water saver kit.
Here is the order I have it in:
Sediment filter
Carbon block
Carbon block
Membranes
Cation
Anion
Mixed bed

My tapwater is around 300 TDS after going through Membranes its 3 and down to zero after the di resins.
I do go through the anion resin quicker than the other two resins.
I tested my mixing station with my hanna phosphorus ulr checker and it reads 200ppb which is the highest it will go so it might be even higher.
I then thought possibly something was leaching out of my container. I have a brand new 30 gallon aquarium that nothing has ever been it so I rinsed it with ro water and then made some new ro/di water and mixed up a small batch of salt and let spin for 24hrs to make sure it was completely dissolved.
Unfortunately readings still are the same 200ppb so my leaching theory is gone
I ordered phosphate LR test kit as it can test both fresh and saltwater.
I also got ATI icp test kit coming as they do both salt water and RO/DI water hopefully both are here tomorrow.
I'm trying to eliminate my water source first then my next step would be my salt mix which is reef crystals.
Anyone have this issue and how did you resolve it?

 

[ShepherdReefer]

We clean our mixing station every other time. Use a mixture of tap water and citric acid, then hand dry.

 

[Joe Sifuentes]

We clean our mixing station every other time. Use a mixture of tap water and citric acid, then

We clean our mixing station every other time. Use a mixture of tap water and citric acid, then hand dry.

I conducted a 2nd test with a brand new 30 gallon tank that has never had anything in it I rinsed out with ro/di water and still have the same results with my hanna ulr phosphorus tester so I've eliminated the container. I tested my aquarium and got 34 ppb so my hanna checked seems to be working. It's either my water source or I have a contaminated batch of salt.

 

[ShepherdReefer]

Joe, could be the water or salt. that is what we do.