Controlling Phosphates

[pbarrett520]

I'm fighting a cyano outbreak right now. The stringy red slime plus the purple slime. I took a sample into the lab at the georgia aquarium where I intern this morning and ran some tests. Phosphates came out at 0.26 ppm. Chart for the acceptable parameters on their softie/cuttlefish tank put phosphate at ND(Not Detectable, since you can never truly have "zero" phospahtes) to 0.20, so my levels are pretty high. Everything else checked out fine. I've got a bag of phosguard in the filter and that's barely keeping it at bay. The only real long term solutions I can think of are to upgrade my skimmer and get more/better detritivores. I'm also thinking about switching to live food and cultivating some pods and phytoplankton. Anyone have any comments or advice? How do y'all keep phosphates in check?

[bertoni]

With the phosphate level that high, the PhosGuard might be exhausted in a few hours. You can measure the output of the phosphate reactor to check. If the level matches that of the tank, the media is shot.

I suspect you'll need to reduce feeding to keep the level under control, but there are other sources of phosphate. I might start by checking some freshly-mixed saltwater. How much live rock is in the system? Is the nitrate level measurably above zero?

[pbarrett520]

With the phosphate level that high, the PhosGuard might be exhausted in a few hours. You can measure the output of the phosphate reactor to check. If the level matches that of the tank, the media is shot.

I suspect you'll need to reduce feeding to keep the level under control, but there are other sources of phosphate. I might start by checking some freshly-mixed saltwater. How much live rock is in the system? Is the nitrate level measurably above zero?

I've been changing the phosguard every 4 days. And I've only been feeding about once every third day. And it's a 28 gallon tank with about 30lbs of LR, I haven't tested nitrate but I'm sure it's above zero. The tank is less than a month old, so I'm fighting new tank syndrome. Do you think maybe a better skimmer would help? Mine is one of those cheapo coralife that's just a tube with a balsa wood airstone. It only ever works right about 1/3 of the time and even then it barely pulls anything.

[pbarrett520]

The vast majority of this rock was dry when it went in btw. Only about 3-4lbs of it was actually live starting out. Same goes for the sand.

[tmz]

I keep mine in the sub 0.05ppm area with organic carbon dosing which is one way among many.

[bertoni]

A better skimmer might be a good investment, but I don't have any recommendations. How much food (and what type) is going into the tank when you feed?

[Dan_P]

I've been changing the phosguard every 4 days. And I've only been feeding about once every third day. And it's a 28 gallon tank with about 30lbs of LR, I haven't tested nitrate but I'm sure it's above zero. The tank is less than a month old, so I'm fighting new tank syndrome. Do you think maybe a better skimmer would help? Mine is one of those cheapo coralife that's just a tube with a balsa wood airstone. It only ever works right about 1/3 of the time and even then it barely pulls anything.

There is no such thing as new tank syndrome. Your aquarium stocking level may be higher than the biofilter size. Also sounds like phosphate export is too small.

Starving your fish is never the correct approach for managing phosphate levels.

With a tank so young, your skimmer may not have enough organics and microorganisms to collect. A better skimmer may help, but don't be surprised if it does not alter nitrate and phosphate levels.

Unless media is in a reactor or very strong flow, it may have inadequate flow to work. Changing media every four days without impacting the phosphate level sounds like this may be your issue.