Question on phosphates

[Spotted]

Where do the phosphates come from? From all my reading it would seem that tap water is the main source.
I ask because I have phosphate readings in my tank. I don't remember off hand, but I want to be able to control it. What can I do to prevent or eliminate my phosphates.
I used water from my lfs. Converting to ro/di once my filter gets here (7 stage aquasafe w/3 di stages for 123 with shipping). But still curious as to how to control it.
I currently have 120# of aragonite live sand and 55# of LR in my 120 fowlr tank. Once funds allow I am ordering another 50# base rock. Filtration consists of an eheim 2080 canister. I know canisters are nitrate factories, but I have not had a nitrate reading since my cycle ended 12/19. Ammonia is spiking a bit lately. 25ppm and nitrite is flat 0.
Bio load is small, now. 1 coral beauty and 1 yellowtail damsel. 10 XL cerinths, 10 turbos, and 20 nass something snails.
Any suggestions?

 

[MikeYQM]

Phosphates come from organics. Food, waste, death, water. They are normally controlled through basic husbandry, but phosphate binders (phosban, phosguard etc), carbon dosing and macro algae culture can be highly effective.

Undetectable phosphate levels are ideal And should be your goal (as with ammonia btw - especially ammonia). If you want some good science I suggest you read the Randy Holmes-Farley articles on the subject.

 

[MikeYQM]

Reading further, 50lbs is not much rock, and considering the other 50lbs will be base, it will take quite some time before your bacteria levels are built enough to support more livestock.

 

[Jason M]

Yeah and u will have nitrates when nitrite gets processed

 

[Spotted]

Yes I do not intend to get anymore fish for a bit.

 

[Rutrag]

Many people use grannular ferric oxide (GFO) in a reactor to bind phosphates as well. I have also use Phoszorb and a phosphate removing pad (can't remember the brand) as well. Phosphate can also come from the foods you feed with flake supposedly being the worst for it. I'm no biochemist, but I understand that some phosphate is necessary to make proteins, so it cannot be wholly eliminated from foods, but I think it's the way dry foods are processed that concentrates it.