Trying To Better Understand Phosphates.

Hey 3reefers!

I recently tested my water a few days ago and my phosphate results came out to be at 0.5 ppm. I want to know how "bad" is that? Now, I know that ideally you want your phosphates to be at 0 (even though its practically impossible to lower it to 0 since everything contains phosphates). I just did a 25% water change today so that my phosphate levels should decrease.

My question exactly is how bad is is 0.5 ppm. Will it promote algae growth to extensive levels? I keep reading on this forum and see people write that "oh 0.5 is horrible, you should be at 0.05" and I hear others saying you shouldn't be concerned until its over 1.0 ppm. My rocks do have some unwanted greeness to it, and my sand produces some brown algae on top (which I cleaned off during my water change). I just want to get everyones input since I am considering running some GFO or something similar to not give any unwanted algae growth a living chance. I don't want to wait to have a big algae problem first before I become more concerned about it.

I use the API Reef Master Test Kit, and I attached an image of the phosphate test's color card so you all can see the scale that API uses.



Thank you everyone!

 

phosphates are just another nutrient in water that algae uses for food.You do want .05 or less,when you hear of people talking about levels that are over 1,they are usually speaking of TDS(total dissolved solids)which is measured in ppm,and tds can include anything that is not 100% pure water.Typically the only time you measure for TDS,it is when the water comes out of your ro/di unit,if you get a reading of 1,that would mean there is too many contaminates getting through your ro/di indicating it's time to change the di resin and/or filters and membrane of your ro unit.Phosphates and nitrates are 2 of the biggest sources of food for algae,and the ro units job is to remove these as well as any other contaminates,but fish food,fish waste,something dead in the rocks such as a snail or similar can all add these 2 to your tank anyhow.If you have a proper amount of bacteria in your tank,it can consume some or most of your nitrates,keeping them in check typically.To reduce phosphates,there are many brands of chemical removers as well as doing water changes with ro/di water with a 0 TDS reading,a refugium could also be added as a natual way to remove these 2,i hear many speaking of adding a combo of cheato algea and mangrove plants to suck up these excessive nutrients.Hope this helps.Overfeeding tends to be a big contributor to elevated numbers.

 

First I will say that any reading on a API kit as a lot. API kit are darn near usless for our applications and are really only a gross measurment of lots of PO4.

PO4 can hinder calcification by corals above .02. So they can inhibit growth above .02. Algae itself isn't necessarily bad, but it can cover and out compete corals for light. So it can choke them out. However, algae can still grow at levels below .01. .01 is pretty hard to attain unless you have employed a few stratagies at lowering them.

GFO is expensive and a PITA... but it is generally the best way to remove excess PO4. Thet's IF you are already using nature to do the majority of the work first.

Growing macro algae in a fuge is one way. We provide optimum lighting for algae to grow and allow it to grow sucking up nitrates and phosphates keeping our display tank clean. I have never understood the reasoning to grow macro and Mangroves. Both are good at doing the same job, but need different flows. I'm more than open to an expaination of why both is better, but have not seen any. Cheato is pretty simple to grow and harvest therefore exporting nitrates and phosphates.

Carbon dosing is also good. Now the new rage is solid carbon in the form of bio pellets. I ran them for a while before taking down the tank and they show lots of promise. All the benefits of liqid carbon dosing without any of the dangerous drawback. Easily ran in a cheap media reactor. You should look into them.

Even with the above, it may still be necessary to use GFO.... but onlty to mop up any left over stuff. GFO is way too expensive to be the sole sorce of PO4 reduction. Especially depending on how much PO4 you are inporting with the types of food you use.

 

I see, thank you both for responding!

Powerman, can you post a link of the carbon your talking about? I would like to take a look. Does that carbon basically not release any harmful stuff back out into the water after it collects it?

Also I'm thinking of getting some of Kent's Phosphate Sponge and trying it out. I hear its a great product if used correctly. On the web site it says you can bake this stuff in an oven and reuse it again if you want to. Anyone have any experience with this stuff? I know it would be a PITA to switch out every day since you cant use this for a long time, but i was thinking of using it when needed. Is that a good idea?

or, if i run some GFO how often do i have to switch it out?

 

You could grab one of BRS's Carbon/GFO reactors.

Aquarium Carbon