Phosphates

[Housen]

When my 75 was youngish there were phosphates. They slowly dimished (I had a good skimmer at work). I change my skimmer a year ago and phosphates are creeping up. Is this a problem? Should it be a concern in a FOWLR system? How should I get rid of them or lower them? Any ideas? Thank you.

[leebca]

Your post is about two different subjects. It seems that you are connecting phosphates with the skimmer.

The skimmer does not remove phosphates. There are some phosphates that are connected to protein molecules (called organophosphates) which the skimmer does remove. However, this form of proteins are not that common in the marine aquarium. Organophosphates are toxic, often found in pesticides and hopefully that isn't in your tank to much if any exten. Thus this isn't connected to your concern. However, while on the subject of the skimmer, are you sure the new one was sized properly? Since there no hobby standards regarding skimmer sizing you have to do that yourself. Don't go by what's claimed by the manufacturer. Instead check out this post and follow it for how to properly size a skimmer for your system: What is Water Quality.

To understand phosphate control, it's best to review their sources. Sources include the following (not in any particular order):
1. Additives put into the water (to make whatever chemical changes to the water);
2) Food
3) Source water
4) Certain organic substrates (like the once popular Miracle Mud)

Normal export/removal from the water column includes (not in any particular order):
a) Algae (certain algae-like microbes too)
b) Plants
c) Chemical filters targeting phosphate (e.g. Phosphate reactors)
d) Water changes


You report that your phosphates were higher at one time; decreased; now increased. Something of the above has changed. For instance, your choice of foods have changed or the other sources have changed. Or you had plants/algae growing that you have removed/killed. (Maybe you removed a refugium with growing plants)? Or your source water has changed -- like your purification or before-treatment water quality has changed (to include more phosphates in the post treated water).

So either the adds have increased, the exports have decreased, or a combo of the two. You change/control those you can, increase exports to address more reductions (increasing water changes or adding a chemical filter, for instance).

Marine fish need phosphate in their foods. Don't starve you fish, but you can be a little more conscious of the contents of the foods you use. Avoid those foods that release a lot of juice into the tank -- uneaten nutrients -- which just feeds bacteria and other micro life. Go after and remove uneaten foods.

Sometimes its a maintenance issue that affects such content.

In general fishes are not concerned about phosphates. But it does encourage algae growth -- it's a normal needed nutrient for plants.

The above are the possibilities, but you don't provide enough info for me to sort it out, so you'll need to do some investigating on your own. Good luck!

[Housen]

Thanks Lee. Did not want you to think I had forgotten this. However, I've been checking everything on your list and found two culprits. Now Im rinsing the foods that are juicy to get rid of the juice, switch a couple to gelled foods (Thank you for the other post on food types), and I'm watching my source water which I was surprised to have found an occasional spike in phosphates. Have to check that out. Anyway, after the changes and a 50% water change to cut the phosphates in half, they are slowly going down. Want to again say thanks for your advice and help. Aside benefit -- not as much work cleaning off the sidwalls of the aquarium. Less algae growth. I think I have cut back 'feeding the micro organisms' as you say.

[leebca]

Good news. You're welcome!